Benign prostatic hyperplasia is a non-malignant enlargement of the prostate gland due to stromal and epithelial cell proliferation, commonly causing lower urinary tract symptoms in aging men.

Benign Prostatic Hyperplasia (BPH)

2. Epidemiology

The etiology and risk factors for BPH include ^[1]:

Risk Factor	Explanation
*1. Age*	The single most important risk factor. Histological BPH is virtually universal in very old men. Prostate growth is a continuous process from ~30 years onward. Androgen exposure over decades drives cumulative hyperplasia ^[1]^[3].
*2. Race*	Higher prevalence in Black men (larger prostate volumes, earlier symptom onset) compared to Asian men. However, with westernised diets and ageing populations, prevalence in Asia is converging ^[1].
*3. Diet*	Western diets (high fat, high red meat) are associated with ↑ BPH risk. The mechanism is likely related to obesity and metabolic syndrome effects on hormonal milieu ^[1].
*4. Metabolic syndrome*	HTN, dyslipidaemia, obesity, insulin resistance, and type 2 DM are all associated with ↑ BPH severity. Hyperinsulinaemia may stimulate prostatic growth factors. Sympathetic overactivity in metabolic syndrome also ↑ dynamic component of obstruction ^[1].
*5. Genetics (role unclear)*	Familial clustering is observed. Men with a first-degree relative with BPH requiring surgery before age 60 have a 4× risk. The exact genetic loci remain unclear ^[1].
*6. Growth factors (basic fibroblastic GF, insulin-like GF, etc.)*	These are androgen-dependent growth factors that mediate the stromal–epithelial interaction driving hyperplasia (detailed below) ^[1].
*Androgens (DHT)*	Absolutely essential. Castrated men and those with 5α-reductase deficiency do NOT develop BPH — proving the androgen-dependent nature of the disease ^[3].

High Yield – Risk Factors from Lecture

Risk factors for BPH per the lecture: Age, Race, Diet, Metabolic syndrome, Genetics (role unclear), Growth factors (bFGF, IGF, etc.) ^[1]. The Olmsted County Study showed that rates of AROU increase with increasing age, increasing prostate size, increasing BPH symptoms, and decreasing maximal urine flow rate ^[6].

4. Anatomy and Function of the Prostate

This is extremely high-yield because different diseases affect different zones:

Zone	% of Glandular Tissue	Key Relations	Clinical Significance
*Anterior zone (Anterior fibromuscular stroma)*	Non-glandular	Covers anterior surface	*Fibromuscular, not glandular* — no BPH or cancer here ^[2]
*Central zone*	~25%	*Surrounds ejaculatory ducts*	Rarely affected by cancer (< 8%) ^[2]
*Transitional zone*	~5–10% (young)	Surrounds proximal prostatic urethra	*Common site of BPH (median lobe)* — this zone undergoes massive expansion in BPH ^[2]
*Periurethral zone*	Small glands	*Surrounds prostatic urethra* directly	Also involved in early BPH nodule formation ^[2]
*Peripheral zone*	~70%	Posterolateral aspect	*Common site of prostate cancer and inflammation (posterior lobe)* — palpable on DRE ^[2]

Why BPH is Symptomatic but Prostate Cancer Often Isn't (Early On)

BPH arises in the transitional zone — right around the urethra. So even moderate enlargement compresses the urethra and causes voiding symptoms early.

Prostate cancer arises in the peripheral zone — far from the urethra. It can grow silently for years before it's large enough to compress the urethra or invade surrounding structures. This is why prostate cancer usually presents late with symptoms since it is located at the posterior aspect ^[2].

Testes → Testosterone → (5α-reductase in prostate) → DHT
                                                        ↓
                                           Binds androgen receptors
                                           on epithelial + stromal cells
                                                        ↓
                                           Stimulates cell proliferation
                                           and inhibits apoptosis

Both prostatic epithelial cells and stromal cells express androgen receptors and depend on DHT for growth ^[2].
Two isoforms of 5α-reductase exist:
- Type 1: found in skin, liver (minor role in prostate)
- Type 2: predominant in prostate — this is the therapeutic target of 5α-reductase inhibitors (5ARIs) like finasteride (type 2 selective) and dutasteride (dual type 1+2)

5. Etiology and Pathophysiology

5.2 Pathophysiology — The Three-Component Model

The pathophysiology of symptomatic BPH can be elegantly understood through three components ^[3]^[5]:

BOO from BPH has two sub-components:

Component	Mechanism	Therapeutic Target
*Static component*	*Stromal hyperplasia mediated by DHT via 5α-reductase* → mechanical compression of urethra by enlarged prostate tissue ^[5]	*5α-reductase inhibitors (5ARIs)* — reduce DHT → shrink prostate volume by ~20-30% over 6-12 months
*Dynamic component*	*Smooth muscle hypertrophy and contraction mediated by α1-adrenergic receptors* → functional narrowing of prostatic urethra ^[5]	*α1-adrenergic blockers* — relax smooth muscle → ↓ functional obstruction → rapid symptom relief (days to weeks)

Why are there two components? The prostate stroma contains a large proportion of smooth muscle cells with abundant α1-adrenergic receptors (especially the α1A subtype). Sympathetic nervous system activation (e.g., during stress, cold, or with sympathomimetic drugs) causes contraction of this smooth muscle, worsening obstruction dynamically on top of the fixed static mechanical compression. This is why men with BPH notice worse symptoms when they're stressed, cold, or taking decongestants (which are α-agonists).

6. Classification

Aspect	Histological BPH	Clinical BPH
Definition	Microscopic evidence of hyperplasia	Symptomatic LUTS attributable to BPH
Prevalence	Very high (>80% men >80y)	Much lower (~10% of those with histological BPH)
Clinical relevance	None unless symptomatic	Drives management decisions

The International Prostate Symptom Score (IPSS) is used to quantify the severity of LUTS ^[4]^[5]:

Involves 7 questions covering:
- Voiding symptoms: incomplete emptying, intermittency, weak stream, straining
- Storage symptoms: frequency, urgency, nocturia
Each question scored 0–5 (total 0–35)
Plus a quality of life (QoL) question scored 0–6

IPSS Score	Severity
*1–7*	*Mild*
*8–19*	*Moderate*
*20–35*	*Severe*

IPSS Is NOT Diagnostic

IPSS is used to quantify severity of LUTS, predict treatment response, guide treatment decisions, and monitor response to treatment — it is NOT a diagnostic tool ^[4]. A high IPSS does not mean the patient has BPH; it means they have significant LUTS. The cause still needs to be determined.

Traditional LUTS classification: "FUN" + "DISH" ^[5]:

Phase	Type	Mnemonic	Symptoms	Pathophysiological Basis
*Storage phase*	*Irritative*	Frequency, Urgency, Nocturia	*Frequency* (尿频), *Urgency* (尿急) ± urge incontinence, *Nocturia* (夜尿)	Detrusor overactivity (secondary to BOO), local pathology (stone, UTI, tumour), systemic causes (↑ fluid intake, polyuria from DM/DI)
*Voiding phase*	*Obstructive*	Dribbling, Intermittent, Straining, Hesitancy	*Dribbling* (尿末滴漏), *Intermittent stream* (尿流斷續), *Incomplete emptying* (尿意未盡), *Straining* (谷), *Hesitancy* (等尿), *Weak stream*	BOO from BPH (static + dynamic), urethral stricture, CA prostate; or bladder hypocontractility (nerve or detrusor muscle problem)

BPH typically presents with both obstructive and irritative symptoms, with obstructive symptoms predominating ^[5]
Bladder outlet obstruction typically presents with predominantly voiding symptoms ^[2]
Overactive bladder typically presents with predominantly storage symptoms ^[2]

Type	Onset	Pain	Mechanism	Typical Cause
*Acute retention of urine (AROU)*	*Sudden*	*Painful*	*Normal innervation* — bladder tries to contract but can't overcome obstruction	*BPH*, drugs, constipation ^[4]
*Chronic retention of urine (CROU)*	Gradual	*Usually painless*	*Abnormal innervation* — detrusor hypocontractility, loss of sensation	DM (diabetic cystopathy), neurogenic bladder ^[4]

7. Clinical Features

7.1 Symptoms

BPH presents with LUTS: both obstructive and irritative symptoms, with obstructive >> irritative ^[5].

Voiding (Obstructive) Symptoms — "DISH + Weak Stream":

Symptom	Description	Pathophysiological Basis
*Hesitancy* (等尿)	Delay in initiation of urinary stream	Detrusor must generate ↑ pressure to overcome obstruction; takes longer to build up sufficient pressure to open the compressed urethra
*Weak stream*	Reduced force and calibre of urinary stream	BOO (static + dynamic) → ↑ urethral resistance → reduced flow rate for any given detrusor pressure
*Straining* (谷)	Need to use abdominal muscles to void	*Higher bladder pressure is needed* to overcome obstruction; patient recruits Valsalva manoeuvre to augment intravesical pressure ^[5]
*Intermittency* (尿流斷續)	Stream starts and stops	Detrusor fatigue during prolonged voiding against high resistance; detrusor contracts in waves rather than sustained contraction. Also associated with *residual urine* ^[5]
*Terminal dribbling* (尿末滴漏)	Dribbling at end of micturition	*Weakened pelvic floor* + residual urine in prostatic urethra that drains by gravity after detrusor relaxes ^[5]
*Incomplete emptying* (尿意未盡)	Sensation of residual urine after voiding	Genuinely elevated post-void residual (PVR) due to inability of detrusor to completely empty bladder against obstruction

Storage (Irritative) Symptoms — "FUN":

Symptom	Description	Pathophysiological Basis
*Frequency* (尿频)	Voiding >8 times/day	Incomplete emptying → ↓ functional bladder capacity; secondary detrusor overactivity from BOO; local irritation from UTI/stone
*Urgency* (尿急)	Sudden, compelling desire to void that is difficult to defer	*Detrusor overactivity* — uninhibited detrusor contractions secondary to BOO-induced bladder wall remodelling (ischaemia → denervation supersensitivity) ^[4]
*Nocturia* (夜尿)	Waking ≥1 time at night to void	Multifactorial: ↓ functional bladder capacity, detrusor overactivity, ↑ nocturnal urine production (loss of circadian ADH rhythm in elderly), nocturnal polyuria from CHF/renal disease
*Urge incontinence*	Involuntary leakage associated with urgency	Severe detrusor overactivity overwhelming sphincter resistance

Symptom	Pathophysiological Basis
*Gross haematuria*	*Ruptured dilated bladder neck veins* — chronic BOO causes congestion and dilatation of submucosal veins at the bladder neck and prostatic urethra. These fragile veins rupture, causing painless haematuria ^[4]^[5]
*Fever, dysuria*	*Recurrent UTI* — urinary stasis (↑ PVR) provides a static pool for bacterial colonisation and growth ^[5]
*Strangury* (painful, frequent urination of small volumes with straining)	*Bladder/urethral stones* — urinary stasis → crystal nucleation and growth → stones irritate bladder mucosa ^[4]
*Uraemic symptoms* (nausea, fatigue, anorexia, pruritus)	*Obstructive uropathy* → bilateral hydronephrosis → ↓ GFR → accumulation of uraemic toxins
*Overflow incontinence*	*Chronic retention* — bladder is so distended that intravesical pressure exceeds urethral resistance; urine "overflows" in small amounts, often without sensation
*Sudden, painful inability to void*	*AROU* — acute-on-chronic obstruction, often precipitated by a trigger (see below)

Common precipitating factors ^[4]:

Factor	Mechanism
Constipation	Rectal distension directly compresses the prostatic urethra (*usually NOT a standalone aetiology but rather a precipitating factor with background prostatic enlargement* ^[4])
UTI	Pain → reflex urethral sphincter spasm → ↑ outflow resistance
Anaesthesia or analgesia (especially opioids, anticholinergics)	↓ detrusor contractility (anticholinergic effect); opioids also ↑ sphincter tone
Immobility	*Poor voiding when supine* — gravitational assistance for voiding is lost ^[4]
Painful perianal conditions (thrombosed haemorrhoids, perianal abscess)	Reflex inhibition of micturition from perineal pain
Excessive fluid intake (especially *alcohol*)	Alcohol: diuresis (ADH suppression) + sedation + smooth muscle relaxation of detrusor; combined rapid bladder filling with impaired detrusor contraction
*Drugs*	Sympathomimetics (e.g., pseudoephedrine in cold remedies): ↑ α1-stimulation → ↑ dynamic obstruction. Anticholinergics: ↓ detrusor contraction. Diuretics: rapid bladder filling. Calcium channel blockers: ↓ detrusor contraction

Drug-Precipitated AROU

Always ask about over-the-counter cold medications in a man presenting with AROU. Pseudoephedrine (a sympathomimetic α-agonist found in many decongestants) directly worsens the dynamic component of BOO. Similarly, first-generation antihistamines (e.g., chlorpheniramine) have strong anticholinergic effects that impair detrusor contraction.

7.2 Signs

Sign	Significance
General condition / neurological assessment	Rule out neurological causes of LUTS (e.g., PD, stroke, MS, spinal cord disease — these can cause detrusor overactivity or underactivity) ^[4]
Signs of chronic kidney disease	Pallor, uraemic frost (rare), fluid overload — suggesting obstructive uropathy from chronic BPH

Sign	Significance
*Distended bladder* (palpable/percussible suprapubic mass)	Suggests urinary retention (acute or chronic). In AROU, the bladder is tender; in CROU, it is often non-tender because the sensory stretch fibres have been chronically desensitised ^[4]
Loin tenderness / ballotable kidneys	May suggest hydronephrosis from chronic obstruction

Sign	Significance
*Phimosis*	Tight foreskin can itself cause BOO — must be checked as a co-contributor ^[5]
Meatal stenosis	Another potential cause of BOO
Urethral discharge	Suggests urethritis → consider urethral stricture as alternative cause of LUTS

This is the most important physical examination in a man with LUTS. DRE assesses:

DRE Finding in BPH	Significance
*Smooth, enlarged prostate (>3 finger breadths)*	Consistent with BPH; normal prostate is ~2 FB ^[5]
*Non-tender*	BPH is typically non-tender. Tenderness suggests prostatitis
*Median sulcus present*	The median sulcus (groove between left and right lobes) is preserved in BPH but may be obliterated in advanced BPH or prostate cancer ^[5]
*Rubbery / firm-elastic consistency*	Consistent with benign tissue. Hard/nodular/irregular consistency raises concern for *prostate cancer*
*Anal tone intact*	Important to assess — reduced anal tone suggests neurological cause (e.g., cauda equina syndrome, which can cause urinary retention) ^[5]
Rectal pathology	Assess for rectal masses, loaded rectum (constipation as precipitant)

DRE Pearls

DRE underestimates prostate size — it only palpates the posterior surface (peripheral zone). A prostate that feels "normal" on DRE can still have significant transitional zone enlargement causing obstruction. - A hard, irregular, nodular prostate with loss of median sulcus should raise alarm for prostate cancer → check PSA, consider biopsy. - Always document anal tone — a lax anal sphincter in a patient with urinary retention is a red flag for cauda equina syndrome (surgical emergency!).

Complications of BPH can be understood by level ^[5]:

Level	Complication	Mechanism
*Prostate level*	*Bleeding (ruptured dilated bladder neck veins)*	Chronic congestion → venous dilatation → rupture
*Bladder level*	*AROU*	Acute-on-chronic obstruction, often precipitated
	*Recurrent UTI*	Urinary stasis (↑ PVR) → bacterial growth
	*Bladder stone*	Urinary stasis → crystal nucleation
	Diverticulum	Mucosal herniation through hypertrophied detrusor
	*Chronic retention ± overflow incontinence*	Progressive detrusor failure against chronic obstruction
*Upper tract level*	*Recurrent hydronephrosis*	Back-pressure from chronically full bladder → ureteral obstruction
	Obstructive uropathy	Bilateral hydronephrosis → parenchymal damage
	*Renal failure*	End-stage consequence of bilateral obstructive uropathy

8. Approach to Evaluation — History and Physical Examination

General: neurological screen (gait, lower limb neurology)
Abdomen: distended bladder (palpation + percussion)
Genitalia: phimosis, meatal stenosis
DRE: anal tone, prostate size/consistency/tenderness, median sulcus, rectal pathology ^[5]

High Yield Summary

Definition: BPH = benign proliferation of glandular epithelial + stromal tissue in the transitional zone of the prostate → nodular enlargement → bladder outlet obstruction → LUTS.

Epidemiology: Histological BPH present in >80% of men >80y; only ~10% symptomatic. Symptomatic age typically 50–80y.

Risk Factors: Age, race, diet, metabolic syndrome, genetics (unclear), growth factors (bFGF, IGF, EGF, TGF)

Zonal Anatomy: Transitional zone = BPH; Peripheral zone = cancer

Pathophysiology — Two components of BOO:

Static: stromal hyperplasia (DHT/5α-reductase) → 5ARI target
Dynamic: smooth muscle contraction (α1 receptors) → α-blocker target
Secondary detrusor overactivity (30-60% of BOO patients) → storage symptoms

Clinical Features:

Voiding (obstructive) > Storage (irritative)
Voiding: hesitancy, weak stream, straining, intermittency, terminal dribbling, incomplete emptying
Storage: frequency, urgency, nocturia
Complications by level: prostate (bleeding), bladder (AROU, UTI, stones, diverticula), upper tract (hydronephrosis, renal failure)

DRE in BPH: smooth, enlarged (>3FB), non-tender, median sulcus present, rubbery, anal tone intact

IPSS: Mild 1–7, Moderate 8–19, Severe 20–35 (NOT diagnostic — only quantifies severity)

AROU: Most common urological emergency. BPH = 53% of male AROU. Precipitants: constipation, UTI, anaesthesia, drugs, immobility, alcohol.

Active Recall - BPH: Definition, Epidemiology, Anatomy, Pathophysiology, Clinical Features

Differential Diagnosis of BPH (Differential Diagnosis of LUTS in a Man)

The key mental framework here is this: a man walks into clinic with LUTS. You're thinking BPH, but what else could it be? The differential diagnosis is not "what mimics BPH" — it is more accurately "what else causes LUTS in a man?" Because as we established in Part 1, not all LUTS is due to BPH — ≥1/3 of men with LUTS do NOT have BOO ^[4].

The approach to the differential must be systematic and anatomical, working through the possible sites of pathology from the kidneys down to the urethra, plus systemic causes. We also need to think about it physiologically: is the problem with outflow (obstruction), with the bladder (overactivity or underactivity), or with urine production (polyuria)?

Detailed Differential Diagnosis Table

The differential diagnosis of LUTS can be classified by type ^[7]:

Site	Diagnosis	Key Distinguishing Features	Why It Causes LUTS
Prostate	Benign Prostatic Hyperplasia (BPH)	Age >50, smooth enlarged prostate on DRE, median sulcus preserved, gradual onset	Transitional zone hyperplasia → static + dynamic compression of prostatic urethra
	Prostate cancer (CA prostate)	Usually asymptomatic (affects peripheral zone) but can present with LUTS ^[3]. Hard, nodular, irregular prostate on DRE ± loss of median sulcus. Elevated PSA. May present with bone pain (metastases)	Peripheral zone tumour grows large enough to compress urethra, or invades bladder neck/trigone. Remember: peripheral zone location means it's usually silent until advanced ^[3]^[7]
Urethra	Urethral stricture	May have similar LUTS but usually associated with history of prior instrumentation, trauma, or STDs ^[3]. Younger age. May have history of urethritis, catheterisation, hypospadias repair	Scarring narrows the urethral lumen → fixed mechanical obstruction. "Stricture" = Latin strictura = tightening/narrowing
Bladder neck	Bladder neck contracture	Usually from prior urological surgery (e.g., radical prostatectomy) or radiotherapy for CA prostate ^[7]. History of prior procedure is the key clue	Post-surgical/post-RT fibrosis and scarring of the bladder neck → fixed narrowing of the bladder outlet
Bladder	Bladder stones	Irritative symptoms (strangury), intermittent stream (stone acts as ball-valve at bladder neck), haematuria, recurrent UTI, history of urinary stasis	Stone at bladder neck intermittently obstructs outflow; also irritates bladder mucosa causing storage symptoms ^[7]
	Bladder cancer (CA bladder)	Painless haematuria (cardinal symptom), irritative LUTS (frequency, urgency), constitutional symptoms, smoking history (strongest RF)	Tumour at bladder neck/trigone can obstruct outflow; tumour anywhere in bladder irritates mucosa → storage symptoms
Bladder	Interstitial cystitis	Chronic pelvic pain, frequency, urgency, pain relieved by voiding, predominantly in women but occurs in men. No infection on culture	Chronic inflammation of bladder wall → ↓ functional capacity, pain
	Ketamine cystitis	History of ketamine abuse (recreational drug use — relevant in Hong Kong!), severe frequency/urgency/dysuria, contracted bladder	Ketamine and its metabolites are directly toxic to urothelium → severe inflammation, fibrosis, contracted bladder
Functional	Detrusor-sphincter dyssynergia (DSD)	History of spinal cord injury or pontine stroke. Failure of sphincter relaxation during detrusor contraction	Interruption of pontine micturition centre control → synchronous contraction of detrusor AND sphincter → very high pressures → upper tract damage ^[4]
Other	Drugs causing retention	History of sympathomimetics (pseudoephedrine), anticholinergics, opioids, TCAs, beta-blockers	Sympathomimetics: ↑ α1-mediated urethral smooth muscle contraction. Anticholinergics/opioids: ↓ detrusor contractility. Combined effect = functional BOO
	Chronic constipation	Loaded rectum on DRE, history of chronic constipation	Rectal distension compresses prostatic urethra from posterior. Usually a co-factor with background BPH rather than sole cause ^[4]
	Phimosis	Tight foreskin visible on examination, may cause ballooning during micturition	Mechanical obstruction at the level of the prepuce → impeded urinary outflow

Category	Diagnosis	Key Distinguishing Features	Why It Causes LUTS
Neurogenic OAB	Stroke	History of CVA, upper motor neuron signs, loss of cortical inhibition	Frontal cortex normally inhibits the pontine micturition centre during filling. Stroke removes this inhibition → uninhibited detrusor contractions
	Spinal cord injury (SCI)	History of trauma/myelopathy, UMN signs below level of lesion	Suprasacral SCI → loss of descending inhibitory pathways → detrusor overactivity (± DSD)
	Multiple sclerosis (MS)	Young female, relapsing-remitting neuro symptoms, demyelinating lesions on MRI	Demyelination of spinal cord pathways → detrusor overactivity or DSD
	Parkinson's disease (PD)	Resting tremor, bradykinesia, rigidity, postural instability	Basal ganglia normally exert tonic inhibitory influence on pontine micturition centre. Loss of dopaminergic neurons → loss of inhibition → detrusor overactivity
	Normal pressure hydrocephalus (NPH)	Classic triad: gait apraxia, dementia, urinary incontinence	Stretching of periventricular white matter fibres from sacral motor cortex → loss of voluntary control of micturition
Non-neurogenic OAB	Idiopathic OAB	Most common cause. Diagnosis of exclusion. No neurological disease	Unknown mechanism — possibly myogenic changes in detrusor, altered afferent signalling
	Secondary to BOO	OAB itself can be secondary to bladder outlet obstruction ^[7]. Patient has BOTH voiding and storage symptoms	BOO → ↑ intravesical pressure → detrusor hypertrophy → ischaemia → denervation supersensitivity → uninhibited contractions ^[4]
	Bladder pathology	Cystitis (infection), tumour, stones, foreign body, post-RT cystitis	Local irritation of bladder mucosa/detrusor triggers afferent nerve activation → urgency and frequency

Category	Diagnosis	Key Distinguishing Features	Why It Causes LUTS
Infection	UTI / Acute prostatitis	Usually irritative symptoms with dysuria, associated with pyuria + significant bacteriuria on urine culture ^[3]. Fever, tender prostate (prostatitis)	Infection → inflammation of bladder/prostatic mucosa → ↑ afferent nerve firing → urgency, frequency, dysuria
Polyuria	Diabetes mellitus (DM)	Polyuria, polydipsia, weight loss, elevated glucose. Nocturia prominent	Osmotic diuresis from glycosuria → ↑ urine volume → frequency, nocturia. Also: diabetic cystopathy (autonomic neuropathy → detrusor hypocontractility) ^[7]
	Diabetes insipidus (DI)	Nocturnal polyuria from loss of diurnal variation or deficiency of vasopressin (ADH) ^[7]. Very dilute urine, massive volumes	Central DI: ↓ ADH production. Nephrogenic DI: kidney resistant to ADH. Either way → inability to concentrate urine → polyuria
	Excessive fluid intake / Primary polydipsia	Habit of drinking large volumes, psychiatric history	Simply too much water in → too much urine out
Cardiovascular	Congestive heart failure	Peripheral oedema, orthopnoea, PND. Nocturia prominent	During the day, fluid pools in dependent areas (gravity). At night, recumbency → ↑ venous return → ↑ renal perfusion → mobilisation of peripheral oedema → nocturnal polyuria ^[7]
	Peripheral oedema (any cause)	Oedema on examination	Same mechanism as CHF — third-space fluid mobilised at night
Respiratory	Obstructive sleep apnoea (OSA)	Snoring, daytime somnolence, obesity, large neck circumference	Difficulty with sleep maintenance and loss of diurnal variation in release of vasopressin (ADH) ^[7]. Also: ↑ atrial natriuretic peptide (ANP) release from ↑ intrathoracic pressure → natriuresis → nocturnal polyuria

Nocturia deserves special attention because it is extremely common and has a broad differential beyond BPH ^[7]:

System	Cause	Mechanism
Respiratory	OSA	Loss of diurnal variation in ADH release + ↑ ANP ^[7]
Cardiovascular	HTN, CHF, peripheral oedema	Nocturnal mobilisation of third-space fluid → ↑ renal perfusion at night ^[7]
Urological	UTI, BPH, CA prostate	↓ functional bladder capacity (BOO, inflammation) or detrusor overactivity ^[7]
Endocrine	DM, DI	Osmotic diuresis (DM) or nocturnal polyuria from loss of diurnal variation/deficiency of vasopressin (DI) ^[7]

Nocturia Is Not Always Urological!

Many students reflexively attribute nocturia to BPH. But always consider systemic causes — CHF, DM, DI, OSA, excessive evening fluid intake, and medications (diuretics taken in the evening). The voiding diary (frequency-volume chart for ≥3 days) is essential to distinguish nocturnal polyuria (>33% of 24h urine output at night) from reduced functional bladder capacity ^[4]^[5].

Feature	BPH	Prostate Cancer	Urethral Stricture	Neurogenic Bladder	UTI/Prostatitis
Age	50–80	>60 (rare < 40)	Any age	Any age	Any age
Onset	Gradual	Insidious or asymptomatic	Gradual	Variable (depends on neuro lesion)	Acute
Symptom predominance	Voiding > storage	Often asymptomatic; voiding if advanced	Voiding	Storage or voiding (depends on lesion level)	Storage (irritative)
DRE	Smooth, enlarged, non-tender, median sulcus intact	Hard, nodular, irregular, loss of sulcus	Usually normal prostate	Normal prostate; ↓ anal tone if cauda equina	Tender, boggy (prostatitis)
PSA	Mildly elevated (proportional to volume)	Often significantly elevated (> 10 suspicious)	Normal	Normal	Elevated (acute prostatitis)
Key history	None specific	Family history, ethnicity	Prior instrumentation, STD, trauma	Neurological disease history	Fever, dysuria, recent catheter
Urinalysis	Usually normal	Usually normal	Usually normal	Usually normal	Pyuria, bacteriuria

Since PSA is commonly checked in men with LUTS, understanding what elevates PSA beyond cancer is important ^[7]^[8]:

Category	Causes
Benign conditions	BPH (proportional to volume), prostatitis (returns to baseline 6–8 weeks after symptom resolution), prostatic infarction, AROU (↓ by 50% within 1–2 days after resolution; do NOT screen PSA for ≥2 weeks after AROU), perineal trauma ^[8]
Manipulation	Cycling, prostatic massage, DRE (minimal effect), prostate biopsy, TURP, ejaculation (minor, transient) ^[8]
Malignant	Prostate cancer (strongest association with risk and outcome)

PSA interpretation ^[7]^[8]:

PSA < 4 ng/mL = Normal
PSA ≥ 4 ng/mL = Cutoff for considering diagnostic prostate biopsy
PSA 4–10 ng/mL = ~20% chance of cancer (the "grey zone")
PSA ≥ 10 ng/mL = ~50% chance of cancer

PSA Pearl

PSA is prostate-specific but NOT prostate-cancer specific ^[7]^[8]. It goes up with any process that disrupts prostate architecture — infection, hyperplasia, infarction, manipulation. Never diagnose cancer on PSA alone. And do NOT screen PSA if patients have < 10 years of life expectancy unless clinically obvious disease (e.g., palpable nodule on DRE) ^[8].

Investigation	What It Rules In/Out	When to Use
DRE	BPH (smooth, enlarged) vs CA prostate (hard, nodular) vs prostatitis (tender, boggy); anal tone for neurogenic cause	Every patient with LUTS ^[3]^[5]
Urinalysis + C/ST	UTI, haematuria (bladder pathology)	Every patient ^[3]^[5]
Urine cytology	Indicated if bladder cancer suspected — patients presenting with haematuria and predominantly irritative symptoms ^[8]	Haematuria, smoker, irritative-predominant LUTS
PSA	CA prostate (elevated), BPH (mildly elevated proportional to volume)	Controversial; probably measured if diagnosis of CA prostate would change management ^[4]
Uroflowmetry	Qmax > 15 mL/s can effectively rule out clinically important BOO ^[3]. Abnormal flow pattern (multiple peaks = straining)	Routine screening for BOO
Voiding diary (≥3 days)	Distinguishes nocturnal polyuria from reduced bladder capacity; quantifies fluid intake	Especially if frequency/nocturia prominent ^[4]^[5]
Urodynamics	Gold standard for diagnosis of BOO — distinguishes BOO (↓ flow + ↑ detrusor pressure) from detrusor underactivity (↓ flow + ↓ detrusor pressure) ^[3]	Uncertain diagnosis, neurological disease, young age (< 50), failed initial treatment ^[3]
Cystoscopy	To rule out urethral strictures, bladder stones, bladder cancer ^[3]	Haematuria, suspicion of structural pathology
USG upper tract	Hydronephrosis (obstructive uropathy), stones, tumour	If large post-void residual, haematuria, or history of urolithiasis ^[3]
USG prostate (TRUS)	Prostate volume (for 5ARI use, surgical planning), intravesical prostatic protrusion	If contemplating surgery ^[3]^[5]

BOO Is a Urodynamic Diagnosis!

BOO is a urodynamic diagnosis ^[3] — it is defined by ↓ uroflow rate PLUS ↑ detrusor pressure during voiding. Uroflowmetry alone cannot distinguish BOO from detrusor underactivity (both give low flow), which is why urodynamics is the gold standard when the diagnosis is uncertain. This distinction matters because surgery for BOO (e.g., TURP) will NOT help a patient whose problem is a weak detrusor.

Symptom Pattern	Most Likely Diagnoses	Key Differentiating Investigation
Voiding-predominant LUTS in older man	BPH, CA prostate, urethral stricture	DRE, PSA, uroflowmetry, cystoscopy
Storage-predominant LUTS	OAB (neurogenic or idiopathic), UTI, bladder pathology (stones, tumour, cystitis)	Urinalysis, voiding diary, cystoscopy, neurological exam
Mixed LUTS	BPH with secondary OAB, neurogenic bladder	Urodynamics (distinguishes BOO + OAB from other combinations)
Nocturia-predominant	Nocturnal polyuria (CHF, OSA, DM/DI, evening diuretics), BPH, OAB	Voiding diary (≥3 days), glucose, cardiac assessment
LUTS + haematuria	CA bladder, bladder stones, BPH (bleeding veins), CA prostate, UTI	Cystoscopy, urine cytology, CT urogram
LUTS + neurological signs	Neurogenic bladder (stroke, PD, MS, SCI, NPH)	Neurological examination, MRI brain/spine, urodynamics
LUTS in young man (< 50)	Urethral stricture, prostatitis, neurogenic bladder, functional BOO	Cystoscopy, urodynamics, STD screen

High Yield Summary

Core principle: Not all LUTS = BPH. ≥1/3 of men with LUTS do NOT have BOO. Think systematically.

Three categories of LUTS differential:

BOO (voiding symptoms): BPH, CA prostate, urethral stricture, bladder neck contracture, stones, drugs, phimosis
OAB (storage symptoms): Neurogenic (stroke, PD, MS, SCI, NPH) vs Non-neurogenic (idiopathic, secondary to BOO, bladder pathology)
Other: UTI/prostatitis, polyuria (DM, DI, CHF, OSA, polydipsia)

Key differentiating features on DRE: BPH = smooth, enlarged, non-tender. CA prostate = hard, nodular, irregular. Prostatitis = tender, boggy. ↓ Anal tone = neurogenic cause.

PSA: Prostate-specific but NOT cancer-specific. Elevated by BPH, prostatitis, AROU, manipulation. Do NOT check within 2 weeks of AROU.

Nocturia DDx: Don't forget non-urological causes — CHF, OSA, DM/DI, evening diuretics. Voiding diary is essential.

BOO is a urodynamic diagnosis — uroflowmetry alone cannot distinguish BOO from detrusor underactivity.

Active Recall - Differential Diagnosis of BPH / LUTS

References

^[2] Senior notes: felixlai.md (sections on prostate anatomy, epidemiology, differential diagnosis of LUTS) ^[3] Senior notes: Ryan Ho Urogenital.pdf (p172–173, section 8.3.2 BPH diagnosis and D/dx; p130, haematuria approach; p248, urethritis) ^[4] Senior notes: Ryan Ho Fundamentals.pdf (p349–355, LUTS evaluation, AROU approach, IPSS) ^[5] Senior notes: maxim.md (LUTS and BPH overview, investigations) ^[7] Senior notes: felixlai.md (sections on differential diagnosis of LUTS and nocturia — tables on BOO vs OAB causes) ^[8] Senior notes: felixlai.md (sections on PSA interpretation, causes of elevated PSA, urine cytology indications)

Diagnostic Criteria, Diagnostic Algorithm, and Investigations for BPH

3. Investigation Modalities — Detailed Breakdown

I'm going to walk through each investigation in detail, explaining what it is, why we do it, how to interpret it, and its pitfalls. I'll organise them into mandatory (baseline) investigations and optional (selected patients) investigations, mirroring the lecture slides ^[9].

3.1 MANDATORY BASELINE INVESTIGATIONS (For All Patients)

IPSS and QoL scores: assess severity (guide treatment) and risk factor for progression ^[9].

Aspect	Detail
What it is	A validated 7-question self-administered questionnaire + 1 QoL question
What it measures	Voiding symptoms: incomplete emptying, intermittency, weak stream, straining. Storage symptoms: frequency, urgency, nocturia ^[4]
Scoring	Each question 0–5; total 0–35. QoL scored 0–6 separately
Interpretation	Mild (1–7), Moderate (8–19), Severe (20–35) ^[4]
Purpose	Quantify severity of LUTS, predict treatment response, guide Tx decision, and monitor response to Tx ^[3]^[4]
What it is NOT	NOT a diagnostic tool — it doesn't tell you why the patient has LUTS, only how bad it is ^[4]
Clinical use	Guides whether to pursue watchful waiting (mild, not bothersome) vs medical Tx (moderate) vs surgical Tx (severe/refractory). Also used for serial monitoring: if IPSS drops significantly after starting an α-blocker, treatment is working

Voiding diary for at least 3 days, especially if frequency/nocturia ^[5].

Aspect	Detail
What it is	Patient records time and volume of every void + fluid intake for ≥3 days
Why we do it	Distinguishes nocturnal polyuria (> 33% of 24h urine at night) from reduced functional bladder capacity from global polyuria
Key findings	High 24h urine output → polyuria (DM, DI, polydipsia). High nocturnal fraction → nocturnal polyuria (CHF, OSA). Frequent small-volume voids → ↓ functional capacity (OAB, BOO)
Significance	Prevents misattributing nocturia to BPH when the real problem is CHF or nocturnal polyuria

Urine microscopy and culture: rule out UTI ^[9].

Aspect	Detail
What it is	Dipstick ± microscopy ± culture and sensitivity (C/ST)
What to look for	Blood (haematuria → consider CA bladder, stones, BPH bleeding), WBC/pyuria (UTI, prostatitis), bacteria (UTI), nitrites (Gram-negative UTI), glucose (DM as contributor to polyuria) ^[3]^[8]
Why it's essential	UTI can mimic or coexist with BPH. A man with irritative LUTS and pyuria may have a UTI as the primary or contributory cause. You must rule this out before attributing everything to BPH
Urine C/ST	Confirms UTI and guides antibiotic selection

Uroflowmetry and post-void residual urine (PVR) ^[9]:

This is the key objective functional test for BPH evaluation. Let me explain it from first principles.

How it works: The patient urinates into a funnel connected to a weight transducer that measures the volume of urine accumulating per unit time. This generates a flow-time curve. PVR is then measured by ultrasound immediately after voiding.

Validity requirement: Volume voided must be > 150 mL to be representative of usual voiding habit ^[5]. If the patient only voids 50 mL, the test is unreliable — the detrusor may not have generated its maximum contraction.

Parameter	Normal	Abnormal / BPH	Significance
Peak flow rate (Qmax)	> 15 mL/s in males ^[3]^[4]	< 15 mL/s	The lower the Qmax, the higher the probability of BOO
Flow pattern	Bell-shaped (smooth, single peak) ^[3]^[4]	Reduced peak with prolonged tail (BPH); Plateaued/flat (urethral stricture); Multiple peaks (straining pattern) ^[5]	Pattern helps distinguish type of obstruction
Post-void residual	< 50 mL (young), < 100–200 mL acceptable in elderly ^[3]^[4]	> 150 mL concerning	High PVR suggests incomplete emptying → risk of UTI, stones, upper tract damage

Qmax interpretation — probability of BOO ^[9]^[3]^[4]:

Qmax	Probability of BOO	Clinical Implication
< 10 mL/s	~90% obstructed	High probability of BOO. Better outcome after TURP (prognostic value!) ^[5]
10–15 mL/s	~60% obstructed	Equivocal — may need urodynamics to confirm
> 15 mL/s	~30% obstructed (i.e., 90% chance of NO BOO)	Can effectively rule out clinically important BOO ^[3]. But note: 18% with obstruction despite Qmax > 15 mL/s ^[3]^[4]

Uroflowmetry Pitfalls

Uroflowmetry alone is NOT sufficient to diagnose outlet obstruction! ^[3]^[4]. It cannot distinguish BOO from detrusor underactivity (DUA) — both produce ↓ Qmax. A man with a weak bladder (e.g., diabetic cystopathy) will have a low flow rate but the problem is the motor, not the pipe. Also, 18% of men have obstruction despite Qmax > 15 mL/s ^[3]^[4]. So a "normal" Qmax does not completely exclude BOO if symptoms are disproportionately severe.

Uroflow curve patterns — visual interpretation:

Pattern	Appearance	Diagnosis
Normal	Smooth bell-shaped curve, single peak at ~15–25 mL/s	No obstruction
BPH pattern	↓ peak, prolonged flow time, may have slightly irregular contour	BOO from prostatic enlargement
Urethral stricture	Plateaued (flat-topped) curve at low Qmax	Fixed narrowing produces constant low flow regardless of detrusor effort
Straining pattern	Multiple peaks (sawtooth)	Patient is using abdominal straining (Valsalva) to empty, causing intermittent flow bursts ^[5]
DUA pattern	Low, prolonged curve (similar to BPH but with ↓ detrusor pressure on urodynamics)	Weak bladder — uroflowmetry alone cannot distinguish this from BOO

Blood tests ^[9]:

Test	Purpose	Key Findings & Interpretation
CBC and clotting profile	To prepare for surgery ^[9]; anaemia screening	Anaemia may suggest chronic disease or haematuria-related loss
Renal function test (RFT)	Obstructive uropathy ^[9]	High serum creatinine can result from bladder outlet obstruction or underlying renal disease — which should prompt an USG ^[8]. Bilateral hydronephrosis from chronic BPH → ↓ GFR → ↑ creatinine
Glucose	DM is a risk factor for BPH and contributes to LUTS (polyuria, diabetic cystopathy) ^[4]	Elevated glucose → consider DM as co-contributor to LUTS
PSA	Only for patients with life expectancy > 10 years and after detailed counselling. DO NOT CHECK PSA during retention or UTI ^[9]	See dedicated section below

PSA = Prostate-Specific Antigen. It is a serine protease whose physiological role is to liquefy the seminal coagulum after ejaculation. It is produced by both normal and neoplastic prostatic epithelial cells.

Key principles ^[8]^[9]:

Prostate-specific but NOT prostate-cancer specific ^[8]
PSA level predicts prostate volume and risk for BPH progression — PSA > 1.5 ng/mL is a useful marker for prostatic enlargement and predicts an increased risk of BPH progression ^[8]
PSA is controversial in BPH workup — probably not routinely indicated but often taken ^[4]. EAU guideline: measured if diagnosis of CA prostate will change management ^[3]^[4]
DO NOT CHECK PSA during retention or UTI ^[9] — both conditions artificially elevate PSA (disrupted prostate architecture in AROU, inflammation in UTI)

PSA interpretation ^[8]:

PSA Level	Interpretation
< 4 ng/mL	Normal
≥ 4 ng/mL	Cutoff for considering diagnostic prostate biopsy
4–10 ng/mL	~20% chance of cancer ("grey zone")
≥ 10 ng/mL	~50% chance of cancer

Conditions that ↑ PSA ^[8]:

Category	Conditions
Benign	BPH, prostatitis (returns to baseline 6–8 weeks after resolution), prostatic infarction, AROU (↓ by 50% within 1–2 days; do NOT screen PSA for ≥2 weeks after AROU), perineal trauma
Manipulation	Cycling, prostatic massage, prostate biopsy, TURP, ejaculation (minor, transient)
Malignant	Prostate cancer
Drugs that ↓ PSA	5α-reductase inhibitors (reduce PSA by ~50% after 6 months — must multiply measured PSA by 2 for accurate interpretation!)

PSA in BPH — Dual Role

PSA serves two purposes in BPH workup: (1) Rule out prostate cancer — elevated PSA warrants further workup. (2) Predict BPH progression — PSA > 1.5 ng/mL correlates with larger prostate volume and higher risk of AROU/need for surgery. This is why PSA can guide the decision to start a 5ARI (more benefit if prostate > 30–40cc) ^[8]^[9].

KUB: look for stone ^[9].

Aspect	Detail
What it is	Plain abdominal radiograph (Kidneys, Ureters, Bladder)
Why	Detects radio-opaque urinary stones (calcium-containing stones are visible; uric acid and cystine stones may be radiolucent)
Relevance to BPH	Bladder stones (complication of BPH from urinary stasis) may be visible as calcification in the pelvis. Also detects incidental renal stones
Limitations	Cannot visualise soft tissue pathology, radiolucent stones, or upper tract obstruction

3.2 OPTIONAL INVESTIGATIONS (Selected Patients)

Optional investigations ^[9]:

TRUS ^[9]:

Aspect	Detail
What it is	Ultrasound probe inserted per rectum to image the prostate
Indications	Before starting 5α-reductase inhibitors for prostate > 30–40cc (because 5ARIs only work if the prostate is large enough — need to confirm volume). Before surgery to decide modality of surgical intervention ^[9] (prostate volume determines whether TURP, HoLEP, or open prostatectomy is appropriate)
What it measures	Prostate volume (cc), prostate morphology, intravesical prostatic protrusion (IPP) ^[3]
Key findings	Enlarged transitional zone, median lobe enlargement protruding into bladder (IPP). IPP > 10 mm is associated with higher BOO severity and may predict failure of trial without catheter (TWOC)
Limitations	No TRUS finding consistently indicates cancer with certainty — NOT used for staging of prostate cancer ^[8]. Cancer can be hyperechoic, isoechoic, or hypoechoic

Flexible cystoscopy: haematuria ^[9].

Aspect	Detail
What it is	Flexible fibre-optic scope passed per urethra into bladder under local anaesthetic
Indications	Haematuria (to r/o CA bladder, bladder stones), suspected urethral stricture, atypical LUTS. Also used before surgery to assess urethral patency and bladder neck anatomy ^[3]
Key findings in BPH	Enlarged median lobe, trabeculated bladder wall (from detrusor hypertrophy), bladder diverticula, bladder stones. Can also identify bladder tumours, urethral strictures
Why not routine	Invasive (even if flexible), uncomfortable, risk of UTI. Not needed if clinical picture is straightforward BPH

USG / CT urogram: haematuria ^[9].

Aspect	Detail
Indications	Large residual volume (for obstruction), haematuria, or history of urolithiasis ^[3]
USG kidneys	Non-invasive, no radiation. Detects hydronephrosis (back-pressure from BOO), renal stones, renal masses, cortical thinning (chronic obstruction). Also measures kidney size
CT urogram	More sensitive than USG for stones, urothelial tumours, and anatomical detail. Used for haematuria workup to exclude upper tract TCC and RCC. Higher radiation and contrast exposure
Why not routine	Most BPH patients have normal upper tracts. Only needed when clinical suspicion of upper tract involvement

Key findings suggesting upper tract complications:

Bilateral hydronephrosis → chronic retention → obstructive uropathy
Cortical thinning → chronic damage, may be irreversible
Stones → bladder or renal
Renal mass → RCC (separate pathology, needs independent workup)

Urodynamic study: atypical age, suspected neurogenic bladder, history of spinal/pelvic surgery, failed intervention ^[9].

This is the gold standard for diagnosis of BOO ^[3]^[4]. Let me explain the principles from scratch.

Why do we need urodynamics? Uroflowmetry tells you the flow rate is low, but it cannot tell you why. There are two possible scenarios for a low Qmax:

BOO: The outlet is blocked → the detrusor contracts hard (↑ pressure) but flow is still low
Detrusor underactivity (DUA): The bladder muscle is weak → ↓ pressure AND ↓ flow

Urodynamics distinguishes these by simultaneously measuring detrusor pressure AND flow rate.

Procedure ^[3]^[4]:

Catheter insertion: Dual-lumen catheter into bladder (one channel fills bladder with contrast/saline, one measures intravesical pressure)
Rectal balloon catheter: Measures intra-abdominal pressure (as a surrogate)
Detrusor pressure calculation: Detrusor pressure = Intravesical pressure – Intra-abdominal pressure ^[3]^[4]
During filling phase: Assess bladder compliance, capacity, sensation, and presence of uninhibited detrusor contractions (OAB)
During voiding phase: Measure detrusor pressure while simultaneously recording uroflow rate
Additional: EMG of external sphincter (usually not done), contrast cystogram for reflux assessment

Key findings ^[3]^[4]:

Pattern	Detrusor Pressure	Uroflow (Qmax)	Diagnosis
Normal	Normal	Normal	No pathology
BOO	↑ (high)	↓ (low)	Bladder outlet obstruction — the bladder is trying hard but can't get urine out
DUA	↓ (low)	↓ (low)	Detrusor underactivity — the bladder isn't generating enough contractile force
OAB / Detrusor overactivity	Involuntary contractions during filling	Variable	Overactive bladder — uninhibited contractions during filling phase

Indications for urodynamics (not routine! only selected patients) ^[3]^[4]^[9]:

Suspicious for non-BPH cause: history of neurological disease, young age < 50y
Failed initial treatment for presumed BOO (suggests the initial diagnosis may be wrong)
Before surgery if diagnosis is uncertain (you don't want to do a TURP on a patient with DUA — it won't help!)
History of spinal/pelvic surgery ^[9]
Atypical age ^[9]

When Urodynamics Changes Management

Imagine a 45-year-old man with voiding LUTS, Qmax of 8 mL/s, and a history of lumbar disc surgery. Is this BOO from early BPH, or DUA from a neurogenic bladder? Uroflowmetry can't tell you. Urodynamics shows ↓ detrusor pressure + ↓ flow → DUA. TURP would be useless and potentially harmful (removing tissue won't help if the problem is a weak bladder). Instead, this patient needs clean intermittent self-catheterisation (CISC). This is why urodynamics matters.

Urine cytology: indicated if bladder cancer is suspected — patients presenting with haematuria and predominantly irritative symptoms ^[3]^[8].

Aspect	Detail
What it is	Fresh urine sent for cytopathological examination of shed urothelial cells
Sensitivity	Overall ~50%, highest for high-grade CA bladder (can detect CIS before gross lesion visible). Low detection rate for low-grade cancer ^[4]
When to order	Haematuria + irritative symptoms + smoker (high risk for CA bladder). Not routine in straightforward BPH

Investigation	Category	Purpose	Key Thresholds / Findings
IPSS + QoL	Mandatory	Quantify LUTS severity, guide Tx	Mild 1–7, Moderate 8–19, Severe 20–35
Voiding diary ≥ 3 days	Mandatory	Distinguish polyuria vs ↓ capacity	Nocturnal fraction > 33% = nocturnal polyuria
Urinalysis + C/ST	Mandatory	R/o UTI, detect haematuria	Pyuria, bacteriuria, haematuria
Uroflowmetry + PVR	Mandatory	Screen for BOO, assess emptying	Qmax < 15 = suspicious; PVR > 150 = concerning
RFT	Mandatory	R/o obstructive uropathy	↑ Creatinine → prompt USG
CBC + clotting	Mandatory	Surgical preparation, anaemia	—
PSA	Mandatory (if life expectancy > 10y)	R/o CA prostate, predict BPH progression	< 4 normal; 4–10 grey zone (20% CA); ≥ 10 suspicious (50% CA)
KUB	Mandatory	R/o stones	Radio-opaque calcification in pelvis
TRUS	Optional	Prostate volume for 5ARI/surgery planning	> 30–40cc for 5ARI; determines surgical approach
Cystoscopy	Optional	R/o stricture, stones, CA bladder	Trabeculation, diverticula, median lobe, stones, tumour
USG / CT upper tract	Optional	R/o hydronephrosis, stones, tumour	Bilateral hydronephrosis, cortical thinning, masses
Urodynamics	Optional	Gold standard for BOO diagnosis	BOO: ↑ Pdet + ↓ Qmax; DUA: ↓ Pdet + ↓ Qmax
Urine cytology	Optional	Screen for CA bladder	High-grade urothelial cells

To make this practical, here's how the investigations flow depending on the clinical picture:

Scenario	Baseline +	Additional Investigations Needed
Straightforward BPH (man > 50, voiding LUTS, smooth enlarged prostate, no red flags)	IPSS, urinalysis, uroflowmetry, RFT, PSA	Usually none — treat empirically
Haematuria present	As above	Cystoscopy (r/o CA bladder), USG/CT urogram (upper tract), urine cytology if irritative symptoms/smoker ^[3]^[9]
Large PVR (> 150 mL) or ↑ creatinine	As above	USG upper tract (hydronephrosis?), USG prostate (volume for surgical planning)
Young patient (< 50y)	As above	Urodynamics (r/o DUA, neurogenic bladder), consider cystoscopy (stricture?) ^[9]
History of neurological disease	As above	Urodynamics (mandatory — LUTS more likely due to neurogenic cause) ^[3]^[9]
Failed initial medical treatment	As above	Urodynamics (confirm BOO before surgery), cystoscopy
Considering 5ARI therapy	As above	TRUS to confirm prostate > 30–40cc ^[9]
Considering surgery	As above	TRUS (volume → choose surgical modality), urodynamics if diagnosis uncertain ^[9]

High Yield Summary

Diagnosis of BPH is presumptive and clinical:

History of voiding-predominant LUTS in a man > 50y
DRE: smooth, enlarged (> 3FB), firm, no nodules, intact median groove
Supported by uroflowmetry (↓ Qmax) and exclusion of other causes

Mandatory investigations for ALL patients:

IPSS + QoL (severity, guide Tx), voiding diary ≥ 3 days, urinalysis + C/ST, uroflowmetry + PVR, RFT, CBC, PSA (if life expectancy > 10y + after counselling), KUB

Key uroflowmetry interpretation:

Qmax < 10: ~90% BOO; 10–15: ~60% BOO; > 15: ~90% no BOO
Volume voided must be > 150 mL for valid test
Cannot distinguish BOO from DUA — urodynamics needed for this

PSA rules:

DO NOT check during AROU or UTI
PSA > 1.5 predicts BPH progression; PSA ≥ 4 warrants consideration of biopsy; PSA ≥ 10 → 50% chance of cancer
5ARIs halve PSA — multiply by 2 for true value

Optional investigations — know the indications:

TRUS: before 5ARI (prostate > 30–40cc) or before surgery
Cystoscopy: haematuria, suspected stricture/CA bladder
Urodynamics: gold standard for BOO; indicated for atypical age, neurological disease, failed treatment, pre-surgical uncertainty
USG upper tract: large PVR, haematuria, stone history

Urodynamics key patterns: BOO = ↑ Pdet + ↓ Qmax; DUA = ↓ Pdet + ↓ Qmax

Active Recall - Diagnosis and Investigations of BPH

References

^[2] Senior notes: felixlai.md (sections on prostate anatomy, BPH overview, investigations) ^[3] Senior notes: Ryan Ho Urogenital.pdf (p170–173, LUTS evaluation, uroflowmetry, urodynamics, BPH diagnosis and investigations) ^[4] Senior notes: Ryan Ho Fundamentals.pdf (p355–357, LUTS approach, IPSS, uroflowmetry, urodynamics) ^[5] Senior notes: maxim.md (BPH investigations section — IPSS, voiding diary, uroflowmetry, TRUS) ^[8] Senior notes: felixlai.md (sections on PSA interpretation, urine cytology, causes of elevated PSA) ^[9] Lecture slides: Benign Prostatic Hyperplasia.pdf (p12, p18 — investigations mandatory and optional)

Management of BPH — Algorithm, Treatment Modalities, Indications and Contraindications

Aspect	Detail
Who	Mild/moderate symptoms, not bothersome ^[3] — i.e. IPSS 1-7 or even moderate IPSS with good QoL
What it involves	Lifestyle advice only ^[3]
Rationale	BPH often progresses slowly. Many men have stable symptoms for years. Intervention carries side effects. If symptoms aren't bothering the patient, the risk-benefit of treatment doesn't favour intervention

Lifestyle modifications ^[8]^[5]:

Avoid fluids prior to bedtime or before going out ^[8] — reduces nocturia and urgency episodes when away from toilet
Reduce consumption of caffeine and alcohol ^[8] — caffeine is a bladder irritant (stimulates detrusor); alcohol is a diuretic (ADH suppression) + sedating (may impair ability to wake for nocturia)
Double voiding to empty bladder more completely ^[8] — void, wait 30 seconds, try again; allows residual urine in the prostatic urethra to drain
Timed voiding — urinate by the clock (every 2-3 hours) rather than waiting for urgency
Bladder training — gradually increase intervals between voids to increase functional capacity
Review medications — stop or substitute drugs that worsen LUTS (anticholinergics, sympathomimetics, diuretics timing)
Manage constipation — loaded rectum compresses urethra

4. Medical Treatment

α-blockers ^[10] are the most commonly prescribed first-line medical therapy for BPH.

Mechanism of action — from first principles:

The prostate stroma is rich in smooth muscle with abundant α1-adrenergic receptors (particularly the α1A subtype). Sympathetic nervous system activation causes contraction of this smooth muscle → dynamic component of BOO. α-blockers inhibit contraction of bladder neck/prostatic smooth muscle (controlled by α1A adrenergic receptors) → ↓ dynamic component of obstruction ^[3].

Think of it this way: the prostate has two elements squeezing the urethra — tissue bulk (static, from hyperplasia) and muscle tone (dynamic, from α1 receptor-mediated contraction). α-blockers relax the muscle tone.

Feature	Detail
MoA	Block α1-adrenergic receptors on prostatic/bladder neck smooth muscle → relaxation → ↓ dynamic obstruction ^[3]
Efficacy	30-40% ↓ IPSS and 16-25% ↑ uroflow ^[3]. Onset ~3 days (cf > 6 months for 5ARI) ^[3]. More effective than 5ARI in both short and long-term for symptom relief
Key limitation	No effect on PSA or prostate size ^[3] → no effect on long-term risk of AROU or need for surgery ^[3]. They treat symptoms but don't modify disease progression
Indications	Moderate-to-severe LUTS (not storage-predominant) ^[3]

Drug classification — uroselective vs non-selective:

Type	Drugs	Selectivity	Advantages	Disadvantages
Non-selective α1-blockers	Prazosin (Minipress), Terazosin (Hytrin), Doxazosin (Cardura), Alfuzosin (Xatral) ^[5]	Block α1A, α1B, α1D equally	Originally developed as anti-hypertensives — can be useful if patient also has HTN	More orthostatic hypotension, nasal congestion, dizziness, tiredness ^[5] — because α1B on blood vessels is also blocked → vasodilation → ↓ BP
Selective α1A-blockers (uroselective)	Tamsulosin (Harnal/Flomax), Silodosin (Rapaflo) ^[5]	Selective for α1A subtype (predominant in prostate)	↓ effect on vessels, BP and HR → fewer cardiovascular side effects	More retrograde ejaculation ^[5] — because α1A receptors also control bladder neck closure during ejaculation; blocking them → semen goes backward into bladder

Side effects of α-blockers ^[3]^[5]^[11]:

General: postural hypotension (5%), dizziness (5-15%), lethargy (5-15%), headache (5-15%) ^[3]
Sexual: abnormal ejaculation / anejaculation is more common with uroselective agents, especially tamsulosin and silodosin; this is now thought to be reduced or absent seminal emission rather than true retrograde ejaculation in many cases ^[11]
Intraoperative floppy iris syndrome (IFIS): α1A receptors are present in the iris dilator muscle. α-blockers (especially tamsulosin) can cause the iris to billow and prolapse during cataract surgery. Always ask about ophthalmic surgical plans before starting!

To reduce side effects: slow titration, subtype-selective (α1A), slow-release formulations ^[5].

α-Blocker Pearl — Speed vs Disease Modification

α-blockers work fast (days) and are great for symptom relief, but they do not shrink the prostate and do not prevent disease progression (AROU, need for surgery). Think of them as "opening the tap" by relaxing the muscle squeeze, but the underlying tissue mass keeps growing. This is why we add 5ARIs for patients at risk of progression.

5α-reductase inhibitors ^[10]:

Mechanism of action — from first principles:

The name tells you the target: 5α-reductase is the enzyme that converts testosterone → DHT (the more potent androgen driving prostatic growth). By inhibiting this enzyme, 5ARIs reduce DHT → decrease size of prostate + decrease vascularity (less bleeding) + progression prevention ^[5].

Feature	Detail
Drugs	Finasteride (Proscar) — type 2 selective; Dutasteride (Avodart) — dual type 1 + 2 inhibitor ^[3]
MoA	↓ conversion of testosterone into DHT → ↓ prostate size → ↓ mechanical (static) component of obstruction ^[3]
Efficacy	↓ prostate size ~20%, ↓ risk of urinary retention and surgery (10-15%) — benefit NOT seen with α-blockers alone ^[3]. But takes 6-12 months to be effective (patient should be informed!) ^[3]
Indications	Moderate-to-severe LUTS + large prostate (> 30-40 mL) ^[3]. Preferred for larger glands ≥ 30-40 mL (TRUS) / IPSS ≥ 12 ^[5]. Also used for BPH-related haematuria (↓ prostatic vascularity → ↓ bleeding)
Why size matters	5ARIs shrink the gland by ~20%. If the prostate is 20g, a 20% reduction is only 4g — clinically insignificant. But if it's 60g, a 20% reduction is 12g — much more meaningful. This is why TRUS to confirm prostate > 30-40cc is recommended before starting 5ARI ^[9]

Side effects of 5ARIs ^[3]^[5]^[11]:

Sexual dysfunction: ↓ libido, erectile dysfunction, ejaculatory disorders ^[3]
Gynaecomastia (1%) ^[3] — ↓ DHT → altered androgen/oestrogen ratio → breast tissue proliferation
Depression has been reported and patients should be counselled to seek review for mood symptoms; current evidence does not prove a consistent suicide-risk signal ^[11]
Effect on PSA: 50% decrease in PSA ^[5] — critical clinical point: multiply PSA by 2 when screening for CA prostate in a patient on 5ARI ^[5]
Effect on CA prostate: trials showed fewer overall prostate cancer diagnoses but more high-grade cancers; a causal relationship has not been proven. Evaluate for CA prostate by DRE and PSA before starting ^[11]

The PSA Halving Rule

A man on finasteride has a PSA of 3.0 ng/mL. His true PSA is approximately 6.0 ng/mL (3.0 × 2). This puts him above the 4 ng/mL biopsy threshold! If you don't adjust for the 5ARI effect, you'll miss a potentially significant PSA elevation. Always multiply measured PSA by 2 in patients on 5ARIs ^[5].

α1-blocker + 5ARI ^[3]:

Feature	Detail
Drugs	Duodart (dutasteride + tamsulosin) ^[3] — single combination pill
Indications	Moderate-to-severe LUTS + ↑ risk of disease progression ^[3] (large prostate, high PSA, severe symptoms). Also: severe symptoms, large prostate, or poor response to monotherapy ^[3]
Rationale	α-blocker provides rapid symptom relief (days); 5ARI provides slow but sustained prostate shrinkage and disease modification (months). Together, they address both the dynamic AND static components
Evidence	More effective than either monotherapy alone in ↓ relative risk of BPH clinical progression ^[3]. MTOPS and CombAT trials showed significant reduction in risk of AROU and need for surgery with combination vs monotherapy
Downsides	Combined side effects of both drugs; cost

PDE5 inhibitor (Tadalafil/Cialis) ^[5]:

Mechanism — from first principles:

PDE5 = phosphodiesterase type 5. This enzyme breaks down cGMP (cyclic guanosine monophosphate) in smooth muscle cells. By inhibiting PDE5, cGMP accumulates → smooth muscle relaxation. In the prostate and bladder, this means:

PDE5-mediated reduction in smooth muscle and endothelial cell proliferation ^[8]
Increases smooth muscle relaxation and perfusion to prostate and bladder ^[8]

Feature	Detail
Drug	Tadalafil (Cialis) — daily low-dose (5 mg) ^[8]
Indications	Current guidelines support PDE5 inhibitors for moderate-to-severe LUTS with or without erectile dysfunction; they are especially attractive when ED coexists ^[11]^[12]
Contraindication	Avoid if using nitrate ^[5] — both PDE5I and nitrates ↑ cGMP → synergistic profound vasodilation → life-threatening hypotension
Side effects	Hypotension, blue and blurred vision (cross-reaction with PDE6 in retina ^[8]), hearing loss, flushing, headache, dyspepsia ^[8]
Advantage	Treats both LUTS and ED simultaneously — very appealing for many men

Combination with an α1-blocker can improve IPSS, but the incremental effect is modest; discuss hypotension risk and the patient's priority for erectile function ^[11].

4.5 Drugs for Storage Symptoms — Anticholinergics and β3-Agonists

For patients with storage-predominant LUTS (frequency, urgency, nocturia) or residual storage symptoms after α-blocker treatment:

Anticholinergics for storage symptoms ^[10]:

Mechanism: The detrusor muscle contracts via muscarinic (M3) receptors activated by acetylcholine from parasympathetic nerves. Anticholinergics block these receptors → ↓ uninhibited detrusor contractions → ↓ urgency, frequency.

Feature	Detail
Drugs	Oxybutynin, Solifenacin ^[5]
Indications	Storage-predominant moderate-to-severe LUTS ^[3]; residual storage symptoms after α-blocker/PDE5I treatment ^[3]
Contraindication	C/I if PVR > 150 mL due to risk of AROU ^[5] — if you suppress the detrusor in a patient who already can't empty properly, you'll tip them into retention
Side effects	Dry mouth, dry eye, constipation, cognitive impairment ^[5] — all due to systemic muscarinic blockade (M receptors are everywhere: salivary glands, lacrimal glands, GI tract, CNS)
Caution	Use with caution if post-void residual > 150 mL ^[3] — monitor PVR when initiating

Beta 3 agonist for storage symptoms ^[10]:

Mechanism — from first principles:

The bladder detrusor has β3-adrenergic receptors on its surface. During the storage phase, sympathetic activation of these β3 receptors causes relaxation of detrusor smooth muscle → allows the bladder to fill at low pressure without triggering urge to void. Mirabegron mimics this.

Feature	Detail
Drug	Mirabegron ^[5]
MoA	Activating β3-adrenergic receptors → relaxation of detrusor smooth muscle during urine storage phase ^[8]
Efficacy	Effective as other anticholinergics in reducing frequency, urgency and incontinence ^[8]
Key advantage	Lower anticholinergic burden and less dry mouth/constipation than muscarinic antagonists; urodynamic studies in men with BOO/OAB have not shown adverse voiding effects, but retention can still occur rarely, especially in combination therapy ^[11]
Side effects	Hypertension, UTI, headache, nasopharyngitis; contraindicated in severe uncontrolled hypertension (SBP ≥ 180 or DBP ≥ 110 mmHg) and BP should be checked before and during treatment ^[11]
When to choose	Preferred over anticholinergics when cognitive effects or dry mouth/constipation are concerns; still reassess symptoms and PVR if voiding worsens

Anticholinergic vs β3-Agonist — When to Choose Which

Both treat storage symptoms. Choose anticholinergics when PVR is low (< 150 mL), no cognitive concerns, and drug is affordable. Choose β3-agonist (mirabegron) when cognitive effects or anticholinergic side effects are a concern, but check BP and reassess if voiding symptoms worsen. Mirabegron has a lower retention signal than antimuscarinics, but it is not "zero risk" ^[11].

5. Management of Acute Retention of Urine (AROU)

AROU is the most common urological emergency and frequently occurs in the context of BPH. Management involves:

Urethral catheterisation (first-line) ^[8]^[4]:

Aspect	Detail
Catheter type	14-16 Fr Foley catheter for males (12-14 Fr for females) ^[8]
Procedure	Aseptic technique → intraurethral lignocaine jelly → insert all the way → inflate 10 mL water balloon → withdraw until resistance ^[4]
Monitor	First catheterisation volume: > 500 mL = genuine AROU; > 1000 mL = possible chronic retention ^[8]
Urine	Send for smear, C/ST ^[8]
Monitor post-catheterisation	Q1H urine output — watch for post-obstructive diuresis ^[8]

Contraindications to urethral catheterisation ^[8]:

Absolute: Urethral injury (high-riding prostate, blood at meatus — pelvic trauma)
Relative: Urethral stricture, recent urological surgery (radical prostatectomy, urethral reconstruction)

If urethral catheterisation fails or is contraindicated → Suprapubic catheterisation (SPC) ^[4]:

Trocar inserted 2 finger breadths above pubic symphysis
Contraindications: non-distended bladder, uncorrected bleeding tendency, known/suspected urothelial cancer ^[4]^[8]

Aspect	Detail
When	Catheter placed for ~2 days then attempt TWOC ^[8]
Purpose	Assess whether patient can void independently after swelling/precipitating factor has resolved
Success rate	~40-60% for first-episode AROU. Higher if precipitating factor is reversible (e.g., UTI treated, constipation resolved)
Enhancing success	Start α-blocker before TWOC (tamsulosin for ≥2 days) — relaxes dynamic component → improves chance of voiding
If TWOC fails	Re-catheterise → consider surgical intervention ^[8]

6. Surgical Treatment

Surgical indications ^[3]^[8]:

Type	Indications
Absolute indications (complications of BPH)	Refractory AROU (failed TWOC) ^[3]^[8], Recurrent UTI ^[3]^[8], Recurrent haematuria ^[8], Bladder stones ^[3], Renal insufficiency secondary to BPH (obstructive uropathy) ^[3]^[8]
Relative indication	Bothersome LUTS refractory to or cannot tolerate medical treatment ^[3]^[8]

Absolute Surgical Indications — Mnemonic: 'SHIRU'

Stones (bladder), Haematuria (recurrent), Insufficiency (renal, from obstruction), Retention (refractory AROU, failed TWOC), UTI (recurrent). If any of these are present, surgery is indicated regardless of symptom severity.

Type of procedure is guided by prostate volume ^[3]:

Prostate Volume	Procedure	Details
< 30 mL, no middle lobe	TUIP (Transurethral Incision of Prostate)	Longitudinal incision made in prostate gland → widen bladder neck and prostatic urethra without removal of any prostate tissue ^[3]. ↓ morbidity, but only effective if prostate < 30g ^[3]
30-80 mL	TURP (monopolar or bipolar)	Current standard surgical procedure for bothersome moderate-to-severe LUTS/BPO in this size range ^[11]
30-80 mL	PVP / GreenLight laser, Aquablation, selected MIST	Consider when bleeding risk, ejaculatory preservation, anaesthetic risk, recovery time, or patient preference changes the trade-off ^[11]^[12]
> 80 mL	Endoscopic enucleation (HoLEP/ThuLEP/B-TUEP)	Size-independent, durable option when expertise is available; HoLEP is an alternative to TURP or open prostatectomy ^[11]^[12]
> 80 mL	Open, laparoscopic, or robotic simple prostatectomy	Reserved for very large glands when endoscopic enucleation is unavailable or unsuitable ^[11]

Transurethral Resection of Prostate (TURP) ^[5]^[8]:

Procedure ^[5]:

Spinal anaesthesia, lithotomy position
Cystoscopy performed first
Resectoscope loaded with monopolar or bipolar diathermy loop introduced transurethrally
Prostate tissue is resected under direct vision in strips — like peeling an orange from the inside
Prostate chips evacuated from bladder; bleeding controlled by electrocautery
3-way Foley catheter placed post-op to irrigate bladder with NS to avoid clot retention ^[5]

Monopolar vs Bipolar TURP ^[5]^[8]:

Feature	Monopolar TURP	Bipolar TURP
Irrigant	1.5% glycine (non-conductive) — saline CANNOT be used because it conducts electricity, diffuses power, and does not allow cutting or cauterisation ^[8]	Normal saline — current flows between two electrodes on the resectoscope tip, not through the patient's body ^[5]
TUR syndrome risk	Yes — glycine absorption → dilutional hyponatraemia	No — saline irrigation eliminates the risk of hyponatraemia ^[5]
Efficacy	Durable symptom and flow improvement	Similar short-, mid-, and long-term efficacy to monopolar TURP ^[11]
Safety	Higher TUR syndrome and transfusion/clot retention risk	More favourable perioperative safety profile: avoids TUR syndrome and reduces bleeding-related events ^[11]
Choice	Depends on local equipment and expertise	Depends on local equipment and expertise; often preferred where available because of safety profile

Pre-operative preparation ^[8]:

Antibiotic prophylaxis — recommended for procedures that manipulate the genitourinary tract

Complications of TURP ^[5]^[8]:

Complication	Mechanism	Incidence/Details
Bleeding (haematuria)	Resection of vascular prostatic tissue; secondary trauma or infection	Bleeding requiring blood transfusion ~1% ^[8]
TUR syndrome	Dilutional hyponatraemia + fluid overload + glycine toxicity from systemic absorption of hypotonic irrigating fluid in monopolar TURP ^[5]^[8]	See detailed section below
Retrograde ejaculation	70-80% — due to resection of bladder neck ^[5]^[8]. Bladder neck normally closes during ejaculation to propel semen anterogradely. Post-TURP, the widened bladder neck stays open → semen goes backward into bladder	Most common long-term complication. Infertility but NOT impotence. Counsel pre-op!
Urethral stricture	Urethral instrumentation — mechanical trauma from resectoscope passage ^[5]^[8]	Usually at fossa navicularis or meatus
Incontinence	~1% ^[5]. Urge incontinence (early) — from irritation/OAB. Stress incontinence (late) — from sphincter damage	Rare but devastating
Erectile dysfunction	Thermal/mechanical damage to cavernous nerves running along prostatic capsule ^[8]	Variable reports
Perforation	Over-resection through prostatic capsule	Can form fistula ^[5]
UTI / sepsis	Instrumentation → bacterial introduction	Prophylactic antibiotics mitigate this

TUR Syndrome — Detailed Explanation

TUR syndrome (Post-prostatectomy syndrome) ^[5]^[8]:

This is a potentially life-threatening complication specific to monopolar TURP.

Pathophysiology: Dilutional hyponatraemia + fluid overload + glycine toxicity ^[5]^[8]:

During monopolar TURP, the bladder is irrigated with hypotonic 1.5% glycine solution
Open venous sinuses in the resected prostatic bed absorb this fluid directly into the systemic circulation
This causes:
- Dilutional hyponatraemia → cerebral oedema → confusion, seizures
- Fluid overload → pulmonary oedema, hypertension
- Glycine toxicity → glycine is an inhibitory neurotransmitter in the retina and CNS → visual disturbance, encephalopathy

Risk factors: long operating time (e.g., massive prostate) ^[5] — more resection time = more open sinuses = more absorption.

Symptoms: Nausea (usually first symptom) ^[5], confusion, cerebral oedema, visual disturbance ^[5].

Management: Manage as hyponatraemia — check electrolytes, serum osmolality, volume status ^[5]. Hypertonic saline if symptomatic severe hyponatraemia ^[5]. Stop irrigation. Diuretics for fluid overload.

Prevention ^[5]:

Use bipolar TURP (NS as irrigating fluid) — eliminates the risk entirely
Limit irrigating fluid volume < 1L and irrigation pressure < 60 mmHg ^[5]
Keep operating time short (< 60 minutes ideally)
Experienced surgeon (faster resection = less absorption)

Modality	Mechanism	Indication / Advantage
Transurethral enucleation — HoLEP (Holmium Laser Enucleation of Prostate)	Laser enucleates the BPH adenoma from the capsule → morcellated for removal ^[3]	Large prostates (> 80 mL) where TURP would take too long. Saline irrigation → no TUR syndrome. Provides tissue for histology
PVP (Photoselective Vaporisation of Prostate / Green Laser)	High-power KTP/LBO laser vaporises prostatic tissue	↓ blood loss, ↓ post-op irritative symptoms ^[3]. Useful in patients with bleeding tendency or poor operative risk ^[3]. Disadvantage: no histological specimen ^[3]
TUMT (Transurethral Microwave Therapy)	Microwave energy induces coagulative necrosis of prostate tissue ^[5]	Minimally invasive, can be done under local anaesthesia. Less effective and less durable than TURP
Aquablation	Image-guided robotic waterjet ablation	Alternative to TURP for 30-80 mL glands, especially when ejaculatory preservation matters; 80-150 mL data are promising but comparative durability against enucleation is still evolving ^[11]
UroLift / Prostatic urethral lift (PUL)	Implants hold lateral lobes away from prostatic urethra ^[5]	Preserves ejaculatory function. Best for prostates < 70 mL without obstructing middle lobe; retreatment rates are higher than TURP ^[11]
Rezūm (Steam / Water Vapour Treatment)	Convective water vapour energy induces coagulative necrosis ^[5]	Minimally invasive and ejaculation-sparing; EAU lists water-vapour therapy among techniques under investigation pending stronger comparative data, while other guidelines use it for selected 30-80 mL glands ^[11]^[12]
Prostatic Artery Embolisation (PAE)	Reduce part of blood supply to prostate ^[5] → ischaemic shrinkage	Consider for men wanting minimally invasive treatment who accept less optimal objective outcomes and higher retreatment than TURP; should be done with urology/interventional radiology MDT follow-up ^[11]
Open / laparoscopic / robotic simple prostatectomy	Surgical enucleation of adenoma	Very large prostates (> 80-100 mL) when endoscopic enucleation is unavailable or unsuitable. More morbid but durable ^[11]
Long-term catheterisation	Foley / SPC / CISC ^[5]	For patients unfit for any intervention
Metallic stent	Temporary for very unfit patients ^[5]	Rarely used; complications common

Clinical Scenario	First-Line Management	Key Rationale
Mild LUTS (IPSS 1-7), not bothersome	Watchful waiting + lifestyle advice	Risk of treatment > benefit; many remain stable
Moderate-severe voiding LUTS, small prostate	α1-blocker	Fast onset; targets dynamic component
Moderate-severe LUTS, large prostate ≥ 40 mL	α1-blocker + 5ARI combination	α-blocker for immediate relief; 5ARI for long-term shrinkage and disease modification
Storage-predominant LUTS	Anticholinergic or β3-agonist (check PVR < 150 first)	Targets detrusor overactivity
LUTS ± erectile dysfunction	PDE5 inhibitor (tadalafil 5 mg daily) ± α-blocker	Guideline-supported for moderate-to-severe LUTS even without ED; particularly useful if ED coexists
AROU	Catheterise → α-blocker → TWOC after 2-3 days → surgery if TWOC fails	Emergency decompression → definitive treatment
Complications (AROU refractory, recurrent UTI, stones, haematuria, renal impairment)	Surgery (modality by prostate size)	Absolute surgical indication
Patient unfit for standard surgery	Long-term catheterisation (Foley/SPC/CISC) or selected minimally invasive option (PVP, PAE, PUL, Rezūm)	Least invasive option that provides adequate drainage or acceptable symptom relief

High Yield Summary

Management is tiered: Conservative → Medical → Surgical

Conservative (Watchful Waiting): Mild/not bothersome LUTS. Lifestyle: ↓ caffeine/alcohol, avoid evening fluids, double voiding.

Medical Therapy:

α1-blockers (first-line): Rapid onset (~3 days), ↓ IPSS 30-40%, ↓ dynamic obstruction. No disease modification. SE: postural hypotension, retrograde ejaculation (especially uroselective).
5ARIs (finasteride/dutasteride): Slow onset (6-12 months), ↓ prostate 18-28%, ↓ risk AROU/surgery. For enlarged prostates / progression risk (e.g. > 40 mL). Halves PSA (multiply by 2!). SE: sexual dysfunction, gynaecomastia; counsel about mood symptoms.
Combination (α-blocker + 5ARI): Best for large prostate + high progression risk. More effective than either alone.
PDE5I (tadalafil): For moderate-to-severe LUTS with or without ED. Avoid with nitrates.
Anticholinergics: Storage symptoms. C/I if PVR > 150 mL. SE: dry mouth, constipation, cognitive impairment.
β3-agonist (mirabegron): Storage symptoms. Lower anticholinergic burden; rare retention can occur, especially in combination therapy. Check BP; avoid severe uncontrolled HTN.

AROU Management: Catheterise (14-16 Fr) → first catheterisation volume (> 500 = genuine, > 1000 = chronic) → Q1H urine output → watch for post-obstructive diuresis → TWOC after 2-3 days with α-blocker → surgery if fails.

Surgical Indications (SHIRU): Stones, Haematuria (recurrent), Insufficiency (renal), Retention (refractory), UTI (recurrent).

Surgical Modality by Size: < 30 mL → TUIP; 30-80 mL → TURP/PVP/Aquablation or selected MIST; > 80 mL → endoscopic enucleation (HoLEP/ThuLEP/B-TUEP) or simple prostatectomy if enucleation unavailable.

TURP complications: Bleeding, TUR syndrome (monopolar only — dilutional hypoNa + fluid overload + glycine toxicity; prevented by bipolar), retrograde ejaculation (70-80%), urethral stricture, incontinence (1%).

Active Recall - Management of BPH

References

^[3] Senior notes: Ryan Ho Urogenital.pdf (p173–176, BPH management — watchful waiting, medical treatment, surgical management including TURP, enucleation, ablative techniques) ^[4] Senior notes: Ryan Ho Fundamentals.pdf (p352, p355 — AROU acute management, catheterisation, subsequent workup) ^[5] Senior notes: maxim.md (BPH management section — medical therapy, TURP procedure and complications, minimally invasive therapies) ^[8] Senior notes: felixlai.md (sections on treatment — non-pharmacological, medical, surgical including TURP, AROU management, catheterisation, post-obstructive diuresis, drug details) ^[9] Lecture slides: Benign Prostatic Hyperplasia.pdf (p12, p18 — investigations including TRUS indications) ^[10] Lecture slides: Benign Prostatic Hyperplasia.pdf (p19 — Treatment of BPH: watchful waiting, alpha-blockers, 5ARI, anticholinergics, beta 3 agonist, surgery) ^[11] European Association of Urology (EAU) Guidelines on the Management of Non-neurogenic Male LUTS, 2026 update. ^[12] American Urological Association (AUA) Guideline: Management of Lower Urinary Tract Symptoms Attributed to Benign Prostatic Hyperplasia.

Complications of BPH

Understanding complications of BPH requires you to think in terms of what happens upstream when there's a chronic downstream obstruction. Picture a garden hose with someone stepping on it — pressure builds up behind the blockage, the hose distends, and eventually the entire system upstream fails. That's exactly what happens from the prostatic urethra backward through the bladder, ureters, and kidneys.

Complications of BPH ^[8]^[5]:

Acute retention of urine (AROU)
Hydroureter and hydronephrosis
Bladder stones
Recurrent UTI
Renal failure

These can be organised by the level of the urinary tract affected, moving from the prostate upward ^[5]:

Level	Complications
Prostate level	Bleeding (ruptured dilated bladder neck veins) ^[5]
Bladder level	AROU, chronic retention of urine (CROU) ± overflow incontinence, recurrent UTI, bladder stones, bladder diverticula, detrusor hypertrophy/failure, hernia (from chronic straining) ^[3]^[5]
Upper tract level	Hydroureter and hydronephrosis (recurrent), obstructive uropathy (pyelonephrosis), renal failure ^[3]^[5]^[8]

Let me now walk through each complication in detail, explaining the pathophysiology from first principles.

2.1 Haematuria from BPH

Aspect	Detail
Mechanism	Chronic BOO causes venous congestion at the bladder neck and prostatic urethra. The submucosal veins dilate and become fragile. These ruptured dilated bladder neck veins bleed, producing painless gross or microscopic haematuria ^[3]^[5]
Clinical features	Typically painless, intermittent gross haematuria. May present with clot retention (clots block the bladder outlet → acute inability to void)
Important caveat	Haematuria should be worked up for other pathologies, especially CA (bladder and renal), even if the patient has known BPH ^[3]. BPH-related haematuria is a diagnosis of exclusion — you must rule out malignancy first with cystoscopy, upper tract imaging, and urine cytology
Management	Mild: observation. Severe/clot retention: 3-way Foley catheter + continuous bladder washout (CBW). Medical: 5ARI (finasteride/dutasteride) → ↓ prostatic vascularity → ↓ bleeding. Refractory: surgical intervention (TURP)

Never Assume Haematuria Is 'Just BPH'

An elderly man with known BPH presenting with haematuria is at the peak age for bladder cancer and renal cell carcinoma. Always perform a full haematuria workup (cystoscopy, CT urogram, urine cytology) before attributing haematuria to BPH. Missing a CA bladder is a serious medicolegal pitfall.

3. Bladder-Level Complications

Aspect	Detail
Definition	Sudden, painful inability to void despite a full bladder ^[4]
Epidemiology	Untreated symptomatic BPH has 2.5%/year risk of AROU ^[3]. BPH accounts for ~53% of male AROU ^[4]
Mechanism	The combination of static (tissue bulk) and dynamic (smooth muscle tone) obstruction reaches a critical threshold — often triggered by a precipitating factor that tips the balance. The detrusor, already working hard against chronic obstruction, can no longer generate enough pressure to overcome the outflow resistance → complete failure to void
Precipitating factors	Constipation, UTI, anaesthesia/analgesia (opioids, anticholinergics), immobility, alcohol, sympathomimetics (cold medications), painful perianal conditions ^[4]
Clinical features	Acute suprapubic pain, palpable/percussible tender bladder, inability to pass urine. Agitated patient
Why it's painful	Innervation is intact → stretch receptors in the bladder wall fire maximally → severe visceral pain. This contrasts with CROU where chronic stretch has desensitised the afferents

Acute management of AROU ^[4]^[8]:

Immediate bladder decompression — urethral catheterisation (14-16 Fr Foley) ^[4]
Monitor first catheterisation volume: > 500 mL = genuine AROU; > 1000 mL = possible chronic retention ^[8]
Send urine for C/ST ^[4]
Anticipate complications of decompression (see Section 3.2 below)
Start α-blocker (tamsulosin) at time of catheterisation ^[3]^[4]
Trial without catheter (TWOC) after 1-2 weeks ^[3]^[4]:
- Success (20-40%): perform urodynamic evaluation for confirmation of BOO ^[3]
- Failure: recatheterise → try again 2 weeks later ^[3]
Failed TWOC ×2 → consider ^[3]^[4]:
- Elective TURP: usually ≥ 4-6 weeks from AROU (↓ risk of bleeding and infection) ^[4]
- Clean intermittent self-catheterisation (CISC): as bridge to surgery; advantages include ↑ rate of spontaneous voiding and ↓ complications vs indwelling catheter ^[3]
- Long-term catheterisation: not preferred — associated with risk of UTI/urosepsis, trauma, stones, urethral strictures, prostatitis, and squamous cell carcinoma of bladder ^[3]

3.2 Complications of Bladder Decompression (After Catheterisation)

These are complications that occur after you relieve the obstruction — a separate but related set of problems:

Aspect	Detail
Definition	Diuresis > 200 mL/h for ≥ 2 hours ^[3]^[4]^[8] or > 3L urine in 24 hours ^[3]
Mechanism	Tubular damage → ↓ concentrating ability → rapid fluid and solute loss ^[3]. During chronic obstruction, back-pressure causes renal tubular injury (especially the medullary concentrating gradient). Once obstruction is relieved, the damaged tubules cannot reabsorb sodium and water properly → massive diuresis. Also represents a physiological response to excrete excess fluid retained during obstruction ^[3]^[8]
Risk	Primarily a problem of chronic but not acute retention ^[8] — because chronic retention has had time to accumulate excess fluid and cause tubular damage
Dangers	May result in hyponatraemia, hypokalaemia, hypovolaemia if not monitored ^[3]
Management	Close monitoring of I/O and fluid/electrolyte status ^[3]. Patients normally can manage by increasing oral fluid intake, but isotonic saline replacement is required if unable to do so ^[8]. Aim to replace half of urine output in the past hour ^[3]. Do NOT remove Foley catheter during POD ^[8]

Aspect	Detail
Mechanism	Bladder mucosal disruption with sudden emptying of a greatly distended bladder ^[3] — the stretched mucosa tears as the bladder rapidly collapses
Significance	Usually self-limiting, rarely significant ^[3]
Management	Observation. Rarely needs intervention

Aspect	Detail
Mechanism	Vagovagal response or relief of pelvic venous congestion ^[3] — the distended bladder was compressing pelvic veins, maintaining venous return. Sudden decompression → pooling of blood in pelvic veins → ↓ venous return → ↓ cardiac output → hypotension
Management	IV fluids, Trendelenburg position, monitoring. Usually transient

Aspect	Detail
Definition	Gradual, painless accumulation of large volumes of residual urine (often > 1000 mL) with vague lower abdominal distension ^[4]
Why painless	Unlike AROU, CROU develops slowly. The bladder wall stretches gradually → sensory stretch receptors adapt and desensitise → patient loses the urgency sensation. This is especially common in patients with diabetic cystopathy (autonomic neuropathy → afferent nerve damage) ^[4]
Overflow incontinence	Superimposed in CROU with ↑↑ PVR in bladder ^[3] — the bladder is so full that intravesical pressure exceeds the urethral closing pressure, and urine "leaks" past the obstruction in small amounts. The patient paradoxically complains of incontinence (urine dribbling) despite having a full bladder they cannot empty
Danger	Silent upper tract damage — because there's no pain, patients may present late with advanced hydronephrosis and renal impairment

Aspect	Detail
Mechanism	Chronic urinary stasis (↑ PVR) creates a static pool of warm urine — an ideal culture medium for bacteria. The stagnant urine is not flushed out by normal voiding, allowing bacterial colonisation and ascension ^[5]^[8]
Risk factors	↑ PVR, instrumentation (catheterisation), bladder stones (bacteria adhere to stone surface forming biofilms)
Clinical features	Dysuria, frequency, urgency (irritative symptoms), fever, cloudy/foul-smelling urine. May precipitate AROU (UTI-related pain → reflex sphincter spasm → acute obstruction)
Management	Treat acute UTI with antibiotics guided by C/ST. Address underlying obstruction (medical or surgical treatment of BPH). Reduce PVR

Aspect	Detail
Mechanism	Urinary stasis → urine becomes supersaturated with solutes → crystal nucleation → stone growth. The stagnant urine in the bladder has prolonged contact time with dissolved minerals, allowing crystallisation. Additionally, recurrent UTI (especially with urease-producing organisms like Proteus) can alkalinise urine → struvite stone formation ^[5]^[8]
Clinical features	Strangury (painful, frequent urination of small volumes, expelled slowly only by straining despite severe urgency and feeling of incomplete emptying ^[4]). Intermittent stream (stone acts as ball-valve at bladder neck → stream cuts off suddenly when stone falls into outlet). Terminal haematuria
Investigation	KUB X-ray (radio-opaque stones), USG bladder, cystoscopy
Management	Cystolitholapaxy (endoscopic stone fragmentation and removal) + definitive BPH surgery. Stone removal alone without addressing the obstruction → stone recurrence

Aspect	Detail
Mechanism	Chronic BOO → detrusor hypertrophy → ↑ intravesical pressure during voiding → bladder mucosa herniates between the hypertrophied muscle bundles, forming outpouchings. These are "pulsion" or "false" diverticula (only mucosa herniates, no muscular wall)
Significance	Diverticula cannot empty properly (no muscle to contract) → stasis within the diverticulum → ↑ risk of UTI, stone formation, and rarely squamous cell carcinoma developing within the diverticulum
Detection	Cystoscopy, CT/USG

This is a key pathophysiological progression that explains why BPH can go from "bothersome" to "dangerous":

Stage	What Happens	Clinical Consequence
Compensated	Detrusor hypertrophies to overcome ↑ outflow resistance. Generates higher pressures to push urine past obstruction	Voiding symptoms present but patient can still empty bladder (PVR low). Trabeculated bladder on cystoscopy
Decompensated	Prolonged strain → muscle fibre replacement by collagen → detrusor fibrosis → loss of contractile function	↑↑ PVR, CROU, overflow incontinence. At this point, even removing the obstruction (TURP) may not restore normal voiding because the detrusor itself is damaged — the patient may need long-term CISC

Detrusor Failure — Point of No Return

There's a therapeutic window in BPH management. If you treat the obstruction while the detrusor is still compensated (hypertrophied but functional), the bladder recovers after TURP. But if you wait too long and the detrusor becomes fibrotic and decompensated, surgical relief of obstruction won't restore voiding function. This is one reason why we don't just watch all BPH patients indefinitely — timely intervention matters.

Aspect	Detail
Mechanism	Hernia due to chronic straining ^[3] — repeated Valsalva manoeuvre during voiding chronically raises intra-abdominal pressure → weakens the abdominal wall → inguinal hernia
Significance	Often overlooked as a BPH complication. Ask about groin swelling in men with chronic voiding symptoms

4. Upper Tract Complications

Aspect	Detail
Mechanism	Chronic high intravesical pressure (from BOO) is transmitted retrograde up the ureters → ureteric dilatation (hydroureter) → renal pelvic dilatation (hydronephrosis). The vesicoureteric junction (VUJ) normally prevents reflux, but chronically elevated bladder pressures can overwhelm this mechanism
Clinical features	Often silent in chronic cases. May present with loin pain/fullness. Bilateral in BPH (obstruction is at the bladder outlet, affecting both sides). Can be complicated by pyelonephrosis (infected hydronephrosis) → fever, loin pain, sepsis ^[3]
Investigation	USG kidneys (most sensitive for detecting hydronephrosis), RFT, CT if complicated
Management	Relieve obstruction (catheterisation → definitive BPH surgery). If pyelonephrosis → urgent drainage (nephrostomy) + IV antibiotics

Aspect	Detail
Mechanism	Bilateral hydronephrosis → sustained ↑ pressure in the renal pelvis → compression of renal parenchyma → ↓ GFR → progressive renal impairment. Tubular function is affected early (↓ concentrating ability → polyuria, a seemingly paradoxical finding in obstruction). Glomerular function is affected later (↑ creatinine, uraemia)
Why polyuria occurs	Chronic obstruction damages the medullary concentrating gradient (countercurrent mechanism). The kidneys produce large volumes of dilute urine despite overall ↓ GFR — this is called obstructive polyuria or the "polyuric phase" of obstructive uropathy
Clinical features	Uraemic symptoms: nausea, anorexia, fatigue, pruritus, confusion. Ask for loin pain, fever, polyuria/oliguria/uraemic symptoms ^[3]. May present with post-renal AKI
Investigation	RFT (↑ creatinine, ↑ urea, ↑ K+), USG (bilateral hydronephrosis, cortical thinning), renal scintigraphy (DMSA for split renal function)
Management	Emergency: catheterisation to relieve obstruction → monitor for POD → correct electrolytes. Definitive: BPH surgery once medically optimised
Prognosis	If caught early (before cortical thinning/atrophy), renal function can recover after obstruction is relieved. If chronic with cortical loss → irreversible CKD

These are complications of the surgical treatment itself, not of BPH, but are essential to know:

TURP complications ^[11]^[3]:

Significant complications in ~15-20%, mortality in 0.2-2.5% ^[3]:

Complication	Mechanism	Details
Bleeding	Resection of vascular prostatic tissue, open venous sinuses	3-7% require transfusion ^[3]. Post-op: 3-way Foley + continuous bladder irrigation with NS to prevent clot retention ^[5]
Infection and urosepsis	Urethral instrumentation introduces bacteria	Prophylactic antibiotics mitigate. Rarely life-threatening
Incontinence (1%) ^[11]	Damage to external urethral sphincter during resection	Devastating if occurs. Careful resection below the verumontanum is critical
Strictures or bladder neck stenosis ^[11]	Mechanical/thermal injury from resectoscope passage (urethral stricture) or post-operative scarring at bladder neck	Urethral stricture from instrumentation; bladder neck stenosis from contracture
Perforation → fistula ^[11]	Over-resection through prostatic capsule into surrounding structures	Can form fistula ^[5] — e.g., rectoprostatic fistula
Retrograde ejaculation	Due to resection of bladder neck ^[5]^[11] — the bladder neck normally closes during ejaculation to propel semen antegrade. Post-TURP, the widened neck stays open → semen flows backward into bladder	40-60% ^[3] (some sources 70-80% ^[5]). Penile erection and sexual function are rarely affected ^[3]. Must counsel pre-operatively regarding fertility implications
Erectile dysfunction ^[11]	Thermal/mechanical damage to cavernous nerves along prostatic capsule	5% ^[3]. Uncommon
TUR syndrome ^[11]	Dilutional hyponatraemia due to systemic absorption of glycine during monopolar TURP	See detailed breakdown below

TUR Syndrome — Detailed

TUR syndrome (< 1%) ^[3]:

Aspect	Detail
Pathophysiology	Irrigation fluids used in monopolar TURP (1.5% glycine) are hypotonic ^[3]. Open venous sinuses in the resected prostatic bed absorb this fluid into the systemic circulation → dilutional hyponatraemia + ↓ osmolarity ^[3]. Aggravated by post-operative stress-related ADH release leading to antidiuresis ^[3]. Glycine itself is neurotoxic (inhibitory neurotransmitter in CNS and retina)
Risk factors	Long operating time ^[5], massive prostate, low irrigation pressure not maintained, monopolar (not bipolar) technique
Timing	Na+ lowest 1-2 hours after surgery, but slowly rises afterwards due to glycine uptake into cells ^[3]
Symptoms	Nausea (first symptom) ^[5], confusion, hypertension, visual disturbance (flashing lights), giddiness, seizures, cerebral oedema ^[3]^[5]
Prevention	Avoid non-conductive irrigants: use bipolar technique (NS as irrigation fluid) → no TUR syndrome ^[11]. Limit operation time to < 1 hour ^[3]. Irrigation pressure < 60 mmHg ^[5]. Monitor fluid absorbed: glycine deficit by irrigation and suction → halt procedure at absorption thresholds ^[3]
Management	Stop OT immediately + Na replacement (hypertonic saline if symptomatic) + Lasix (furosemide) ^[3]. Monitor electrolytes, serum osmolality, volume status ^[5]

Bipolar TURP Eliminates TUR Syndrome

Bipolar TURP uses normal saline as the irrigation fluid because the current flows between two electrodes at the instrument tip (not through the patient's body). This eliminates TUR syndrome and gives a more favourable perioperative safety profile, with lower bleeding-related morbidity compared with monopolar TURP while maintaining similar symptom outcomes ^[11].

Complication	Incidence	Mechanism
Bladder neck stenosis and urethral strictures	7-8% ^[3]	Post-surgical scarring and contracture at resection sites; urethral trauma from repeated instrumentation
Urinary incontinence	2% ^[3]	Late stress incontinence from sphincter damage. Urge incontinence (early) → stress incontinence (late) ^[5]
Regrowth of prostate	5% need re-operation in 5 years ^[3]	BPH is a hyperplastic process that continues as long as androgens are present. TURP removes tissue but the remaining transitional zone can re-grow
Ejaculatory dysfunction	40-60%	Retrograde ejaculation persists (permanent anatomical change at bladder neck)
Erectile dysfunction	5% ^[3]	Cavernous nerve injury

Level	Complication	Key Mechanism	Is This a Surgical Indication?
Prostate	Haematuria	Ruptured dilated bladder neck veins	Yes — if recurrent
Bladder	AROU	Acute-on-chronic obstruction, often precipitated	Yes — if refractory (failed TWOC)
	CROU ± overflow incontinence	Chronic obstruction with detrusor failure	Yes (relative)
	Recurrent UTI	Urinary stasis → bacterial colonisation	Yes
	Bladder stones	Urinary stasis → crystallisation	Yes
	Bladder diverticula	Mucosal herniation through hypertrophied detrusor	Not usually on its own
	Hernia	Chronic straining	No
Upper tract	Hydronephrosis	Retrograde pressure transmission from BOO	Yes
	Renal failure	Bilateral hydronephrosis → parenchymal compression	Yes
Treatment	TUR syndrome	Glycine absorption → hyponatraemia + fluid overload (monopolar)	N/A
	Retrograde ejaculation	Bladder neck resection	N/A
	Urethral stricture	Instrumentation injury	N/A

High Yield Summary

Complications of BPH by level:

Prostate: Haematuria (ruptured dilated veins) — always exclude CA before attributing to BPH
Bladder: AROU (2.5%/year if untreated), CROU ± overflow incontinence, recurrent UTI, bladder stones, diverticula, detrusor failure, hernia
Upper tract: Hydronephrosis → obstructive uropathy → renal failure

Complications of decompression (post-catheterisation):

Post-obstructive diuresis ( > 200 mL/h × ≥ 2h; replace half of output; mainly in CROU)
Haemorrhage ex-vacuo (self-limiting)
Transient hypotension (vagovagal/venous pooling)

TURP complications:

Early: Bleeding (3-7% need transfusion), TUR syndrome ( < 1%, monopolar only — hypoNa + glycine toxicity), retrograde ejaculation (40-60%), incontinence (1%), infection, perforation
Late: Stricture/bladder neck stenosis (7-8%), incontinence (2%), regrowth (5% re-op at 5y), ED (5%)

TUR syndrome prevention: Bipolar TURP (NS irrigation), limit OT < 1h, irrigation pressure < 60 mmHg

Absolute surgical indications (SHIRU): Stones, Haematuria (recurrent), Insufficiency (renal), Retention (refractory AROU), UTI (recurrent)

Long-term catheter complications: UTI, stones, strictures, SCC bladder

Active Recall - Complications of BPH

References

^[3] Senior notes: Ryan Ho Urogenital.pdf (p168, p172, p176–177 — AROU complications, BPH clinical presentation and complications, TURP early and late complications) ^[4] Senior notes: Ryan Ho Fundamentals.pdf (p350, p352–353 — AROU management, post-obstructive diuresis, decompression complications) ^[5] Senior notes: maxim.md (BPH clinical features — complications by level, TURP complications including TUR syndrome) ^[8] Senior notes: felixlai.md (BPH complications section, AROU management, post-obstructive diuresis, catheterisation) ^[11] Lecture slides: Benign Prostatic Hyperplasia.pdf (p33 — TURP complications; p35 — EEP advantages over TURP)

High Yield Summary

Definition: BPH = benign proliferation of glandular epithelial + stromal tissue in the transitional zone of the prostate → nodular enlargement → bladder outlet obstruction → LUTS.

Epidemiology: Histological BPH present in >80% of men >80y; only ~10% symptomatic. Symptomatic age typically 50–80y.

Risk Factors: Age, race, diet, metabolic syndrome, genetics (unclear), growth factors (bFGF, IGF, EGF, TGF)

Zonal Anatomy: Transitional zone = BPH; Peripheral zone = cancer

Pathophysiology — Two components of BOO:

Static: stromal hyperplasia (DHT/5α-reductase) → 5ARI target
Dynamic: smooth muscle contraction (α1 receptors) → α-blocker target
Secondary detrusor overactivity (30-60% of BOO patients) → storage symptoms

Clinical Features:

Voiding (obstructive) > Storage (irritative)
Voiding: hesitancy, weak stream, straining, intermittency, terminal dribbling, incomplete emptying
Storage: frequency, urgency, nocturia
Complications by level: prostate (bleeding), bladder (AROU, UTI, stones, diverticula), upper tract (hydronephrosis, renal failure)

DRE in BPH: smooth, enlarged (>3FB), non-tender, median sulcus present, rubbery, anal tone intact

IPSS: Mild 1–7, Moderate 8–19, Severe 20–35 (NOT diagnostic — only quantifies severity)

AROU: Most common urological emergency. BPH = 53% of male AROU. Precipitants: constipation, UTI, anaesthesia, drugs, immobility, alcohol.

High Yield Summary

Core principle: Not all LUTS = BPH. ≥1/3 of men with LUTS do NOT have BOO. Think systematically.

Three categories of LUTS differential:

BOO (voiding symptoms): BPH, CA prostate, urethral stricture, bladder neck contracture, stones, drugs, phimosis
OAB (storage symptoms): Neurogenic (stroke, PD, MS, SCI, NPH) vs Non-neurogenic (idiopathic, secondary to BOO, bladder pathology)
Other: UTI/prostatitis, polyuria (DM, DI, CHF, OSA, polydipsia)

Key differentiating features on DRE: BPH = smooth, enlarged, non-tender. CA prostate = hard, nodular, irregular. Prostatitis = tender, boggy. ↓ Anal tone = neurogenic cause.

PSA: Prostate-specific but NOT cancer-specific. Elevated by BPH, prostatitis, AROU, manipulation. Do NOT check within 2 weeks of AROU.

Nocturia DDx: Don't forget non-urological causes — CHF, OSA, DM/DI, evening diuretics. Voiding diary is essential.

BOO is a urodynamic diagnosis — uroflowmetry alone cannot distinguish BOO from detrusor underactivity.

High Yield Summary

Diagnosis of BPH is presumptive and clinical:

History of voiding-predominant LUTS in a man > 50y
DRE: smooth, enlarged (> 3FB), firm, no nodules, intact median groove
Supported by uroflowmetry (↓ Qmax) and exclusion of other causes

Mandatory investigations for ALL patients:

IPSS + QoL (severity, guide Tx), voiding diary ≥ 3 days, urinalysis + C/ST, uroflowmetry + PVR, RFT, CBC, PSA (if life expectancy > 10y + after counselling), KUB

Key uroflowmetry interpretation:

Qmax < 10: ~90% BOO; 10–15: ~60% BOO; > 15: ~90% no BOO
Volume voided must be > 150 mL for valid test
Cannot distinguish BOO from DUA — urodynamics needed for this

PSA rules:

DO NOT check during AROU or UTI
PSA > 1.5 predicts BPH progression; PSA ≥ 4 warrants consideration of biopsy; PSA ≥ 10 → 50% chance of cancer
5ARIs halve PSA — multiply by 2 for true value

Optional investigations — know the indications:

TRUS: before 5ARI (prostate > 30–40cc) or before surgery
Cystoscopy: haematuria, suspected stricture/CA bladder
Urodynamics: gold standard for BOO; indicated for atypical age, neurological disease, failed treatment, pre-surgical uncertainty
USG upper tract: large PVR, haematuria, stone history

Urodynamics key patterns: BOO = ↑ Pdet + ↓ Qmax; DUA = ↓ Pdet + ↓ Qmax

High Yield Summary

Management is tiered: Conservative → Medical → Surgical

Conservative (Watchful Waiting): Mild/not bothersome LUTS. Lifestyle: ↓ caffeine/alcohol, avoid evening fluids, double voiding.

Medical Therapy:

α1-blockers (first-line): Rapid onset (~3 days), ↓ IPSS 30-40%, ↓ dynamic obstruction. No disease modification. SE: postural hypotension, retrograde ejaculation (especially uroselective).
5ARIs (finasteride/dutasteride): Slow onset (6-12 months), ↓ prostate 18-28%, ↓ risk AROU/surgery. Best for enlarged prostates / progression risk (e.g. > 40 mL). Halves PSA (multiply by 2!). SE: sexual dysfunction, gynaecomastia; counsel about mood symptoms.
Combination (α-blocker + 5ARI): Best for large prostate + high progression risk. More effective than either alone.
PDE5I (tadalafil): For moderate-to-severe LUTS with or without ED. Avoid with nitrates.
Anticholinergics: Storage symptoms. C/I if PVR > 150 mL. SE: dry mouth, constipation, cognitive impairment.
β3-agonist (mirabegron): Storage symptoms. Lower anticholinergic burden; rare retention can occur, especially in combination therapy. Check BP; avoid severe uncontrolled HTN.

Surgical Indications (SHIRU): Stones, Haematuria (recurrent), Insufficiency (renal), Retention (refractory), UTI (recurrent).

High Yield Summary

Complications of BPH by level:

Prostate: Haematuria (ruptured dilated veins) — always exclude CA before attributing to BPH
Bladder: AROU (2.5%/year if untreated), CROU ± overflow incontinence, recurrent UTI, bladder stones, diverticula, detrusor failure, hernia
Upper tract: Hydronephrosis → obstructive uropathy → renal failure

Complications of decompression (post-catheterisation):

Post-obstructive diuresis ( > 200 mL/h × ≥ 2h; replace half of output; mainly in CROU)
Haemorrhage ex-vacuo (self-limiting)
Transient hypotension (vagovagal/venous pooling)

TURP complications:

Early: Bleeding (3-7% need transfusion), TUR syndrome ( < 1%, monopolar only — hypoNa + glycine toxicity), retrograde ejaculation (40-60%), incontinence (1%), infection, perforation
Late: Stricture/bladder neck stenosis (7-8%), incontinence (2%), regrowth (5% re-op at 5y), ED (5%)

TUR syndrome prevention: Bipolar TURP (NS irrigation), limit OT < 1h, irrigation pressure < 60 mmHg

Absolute surgical indications (SHIRU): Stones, Haematuria (recurrent), Insufficiency (renal), Retention (refractory AROU), UTI (recurrent)

Long-term catheter complications: UTI, stones, strictures, SCC bladder

Benign Prostatic Hyperplasia

Benign Prostatic Hyperplasia (BPH)

2. Epidemiology

4. Anatomy and Function of the Prostate

5. Etiology and Pathophysiology

5.2 Pathophysiology — The Three-Component Model

6. Classification

7. Clinical Features

7.1 Symptoms

7.2 Signs

8. Approach to Evaluation — History and Physical Examination

Active Recall - BPH: Definition, Epidemiology, Anatomy, Pathophysiology, Clinical Features

Differential Diagnosis of BPH (Differential Diagnosis of LUTS in a Man)

Detailed Differential Diagnosis Table

Active Recall - Differential Diagnosis of BPH / LUTS

References

Diagnostic Criteria, Diagnostic Algorithm, and Investigations for BPH

2.1 Algorithm Overview

3. Investigation Modalities — Detailed Breakdown

3.1 MANDATORY BASELINE INVESTIGATIONS (For All Patients)

3.2 OPTIONAL INVESTIGATIONS (Selected Patients)

Active Recall - Diagnosis and Investigations of BPH

References

Management of BPH — Algorithm, Treatment Modalities, Indications and Contraindications

4. Medical Treatment

4.5 Drugs for Storage Symptoms — Anticholinergics and β3-Agonists

5. Management of Acute Retention of Urine (AROU)

6. Surgical Treatment

TUR Syndrome — Detailed Explanation

Active Recall - Management of BPH

References

Complications of BPH

2.1 Haematuria from BPH

3. Bladder-Level Complications

3.2 Complications of Bladder Decompression (After Catheterisation)

4. Upper Tract Complications

TUR Syndrome — Detailed

Active Recall - Complications of BPH

References

On this page

Benign Prostatic Hyperplasia

1. Definition

2. Epidemiology

2.1 Prevalence and Incidence

2.2 In Hong Kong

3. Risk Factors

4. Anatomy and Function of the Prostate

4.1 Basic Anatomy

4.2 Zonal Anatomy (McNeal Classification)

4.3 Function of the Prostate

4.4 Hormonal Regulation

5. Etiology and Pathophysiology

5.1 Etiology

5.2 Pathophysiology — The Three-Component Model

Component 1: Bladder Outlet Obstruction (BOO)

Component 2: Detrusor Response and Overactive Bladder (OAB)

Component 3: Complications of Chronic Obstruction

5.3 Pathophysiology Flow Diagram

6. Classification

6.1 Histological vs Clinical BPH

6.2 Classification by Symptom Severity (IPSS)

6.3 LUTS Classification by Phase

6.4 Retention of Urine Classification

7. Clinical Features

7.1 Symptoms

A. Lower Urinary Tract Symptoms (LUTS)

B. Complications-Related Symptoms

C. Precipitating Factors for AROU in BPH

7.2 Signs

A. General Examination

B. Abdominal Examination

C. Genital Examination

D. Digital Rectal Examination (DRE)

E. Summary of Clinical Presentation by Level of Complication

8. Approach to Evaluation — History and Physical Examination

8.1 History-Taking Framework

8.2 Physical Examination Checklist

Active Recall - BPH: Definition, Epidemiology, Anatomy, Pathophysiology, Clinical Features

References

Organising Framework: Three Pathophysiological Categories

Detailed Differential Diagnosis Table

A. Bladder Outlet Obstruction (BOO) — Predominantly Voiding Symptoms

B. Overactive Bladder (OAB) / Detrusor Overactivity — Predominantly Storage Symptoms

C. Other Causes of LUTS

Differential Diagnosis of Nocturia Specifically

Distinguishing BPH from Key Mimics — Clinical Pearls

Causes of Elevated PSA — A Differential Within the Differential

Clinical Approach: Mermaid Diagram

How Investigations Help Differentiate

Summary: Differential Diagnosis by Symptom Pattern

Active Recall - Differential Diagnosis of BPH / LUTS

1. Diagnostic Criteria — How Do We "Diagnose" BPH?

2. Diagnostic Algorithm

3. Investigation Modalities — Detailed Breakdown

3.1 MANDATORY BASELINE INVESTIGATIONS (For All Patients)

A. International Prostate Symptom Score (IPSS)

B. Voiding Diary / Frequency-Volume Chart

C. Urinalysis and Urine Culture

D. Uroflowmetry and Post-Void Residual (PVR)

E. Blood Tests

F. Serum PSA — Detailed Interpretation

G. KUB X-ray

3.2 OPTIONAL INVESTIGATIONS (Selected Patients)

A. Transrectal Ultrasound of Prostate (TRUS)

B. Flexible Cystoscopy

C. Upper Tract Imaging (USG / CT Urogram)

D. Urodynamic Study

E. Urine Cytology

4. Summary Table: Investigations at a Glance

5. Diagnostic Approach by Clinical Scenario

Active Recall - Diagnosis and Investigations of BPH

1. Guiding Principles of BPH Management

2. Management Algorithm Overview

3. Conservative Management — Watchful Waiting

4. Medical Treatment

4.1 α1-Adrenergic Antagonists (α-Blockers) — First-Line for Voiding Symptoms

4.2 5α-Reductase Inhibitors (5ARIs) — For Large Prostates / Disease Modification

4.3 Combination Therapy — α-Blocker + 5ARI

4.4 PDE5 Inhibitors — For LUTS With or Without Erectile Dysfunction

4.5 Drugs for Storage Symptoms — Anticholinergics and β3-Agonists