Rectal Bleeding
Rectal bleeding is the passage of blood from the rectum, which may originate from any site along the gastrointestinal tract and ranges from minor anorectal conditions to life-threatening hemorrhage.
Murtagh Diagnostic Strategy
| Category | Diagnosis | Key Discriminator | Cantonese Question / Finding | Probability |
|---|---|---|---|---|
| Probability Diagnosis | Haemorrhoids | Painless bright red blood after/on stool, prolapsing perianal lump, a/w straining | 「去完大便之後有冇鮮血滴出嚟？有冇嘢凸咗出嚟？」 | ~45% |
| Anal fissure | Pain on defecation + fresh blood; history of constipation [3] | 「去大便開頭有冇好sharp嘅痛？」 | ~20% | |
| Serious Not To Miss | Colorectal carcinoma | Age > 50, change in bowel habit, weight loss, FHx, iron-deficiency anaemia | 「大便習慣有冇變？有冇輕咗磅？屋企人有冇腸癌？」 | ~5% |
| IBD (UC / Crohn's) | Bloody diarrhoea ± mucus, young adult, extraintestinal features (joints, eyes, skin) | 「有冇成日肚瀉帶血同黏液？關節有冇痛？」 | ~3% | |
| Ischaemic colitis | Elderly + CVS risk factors, sudden abdominal pain then bloody diarrhoea | 「有冇突然肚痛之後去血便？有冇心臟病？」 | ~1% | |
| Pitfalls | Diverticular disease | Painless profuse haematochezia, elderly, often self-limiting [2] | 「有冇試過突然間大量出血但冇乜痛？」 | ~5% |
| Colorectal polyp | Often asymptomatic; intermittent occult bleeding; found on screening | 「之前腸鏡有冇發現瘜肉？」 | ~3% | |
| Rectal STI proctitis | MSM, rectal discharge, tenesmus | 「有冇肛交？有冇分泌物？」 | ~2% | |
| Angiodysplasia | Elderly, a/w aortic stenosis (Heyde syndrome) [7], painless, right-sided | 「有冇心瓣膜問題？」 | ~2% | |
| Masquerades | Drugs (NSAIDs, anticoagulants) | Temporal relationship with medication | 「幾時開始食呢啲藥？」 | ~10% |
| Anaemia (iron-deficiency) | Fatigue, pallor, may be the only clue to occult CRC | Pallor on examination; conjunctival pallor | ~5% | |
| UGIB masquerading as PR bleed | 10–15% of severe haematochezia is from brisk UGIB [2] | 「有冇嘔過血或者嘔啡色嘢？」 | ~2% | |
| Trying to Tell Me Something? | Cancer anxiety / grief | Relative recently diagnosed with CRC; health anxiety | 「你最擔心嘅係咩？有冇屋企人最近唔舒服？」 | ~10% |
| Stress / functional | IBS-related symptoms, life stressor | 「最近壓力大唔大？」 | ~5% |
| Time | Task | Cantonese Key Phrases | Why It Scores Marks |
|---|---|---|---|
| 0:00–0:30 | Friendly opening, rapport | 「你好，我係X醫生，今日想同你傾下你嘅情況，方唔方便呀？」(Hello, I'm Dr X, I'd like to chat about your situation today, is that OK?) | Greeting + permission = interpersonal marks |
| 0:30–2:00 | Chief complaint & HPI – open question → SOCRATES for bleeding; relationship of blood to stool; colour; amount; bowel habit changes | 「可唔可以話我知你有咩唔舒服？」→「隻血係咩色？鮮紅定深色？」→「隻血係包住大便、混喺入面、定係自己流出嚟？」→「有冇去少咗或者去多咗大便？」 | Core symptom analysis; discriminates outlet bleeding vs proximal source |
| 2:00–2:30 | Red flags – weight loss, appetite, tenesmus, mucus, abdominal pain, anaemic symptoms | 「有冇輕咗磅？食嘢點呀？有冇覺得成日想去但去唔清？有冇頭暈、氣促？」 | Screens for colorectal cancer & IBD; "must not miss" |
| 2:30–3:30 | PMHx, DHx, FHx, SHx – previous colonoscopy, NSAID/anticoagulant/antiplatelet, family CRC/IBD/polyps, smoking, alcohol, occupation, diet, constipation | 「你之前有冇做過腸鏡？有冇食薄血藥或者止痛藥？屋企人有冇腸癌或者腸病？」 | Drug history & family history high-yield for CRC risk |
| 3:30–4:30 | ICE – uncover hidden agenda | 「你覺得自己有咩問題？」(Idea) →「你最擔心嘅係咩呢？」(Concern) →「你嚟睇醫生，最希望我哋可以點樣幫到你？」(Expectation) | Direct exam marks; the RFC often hides here – e.g. patient fears cancer |
| 4:30–5:15 | Signposting & summarise | 「我總結返，你有鮮血喺大便度已經X個禮拜，冇乜痛…我有冇講漏咗？」 | Shows active listening, scores communication marks |
| 5:15–6:00 | Explain plan, safety-net, close | 「我建議你做啲驗血同安排照腸，如果有大量出血、頭暈或者肚痛加重，要即刻返急症。你有冇嘢想問？」 | Safe closure + red-flag safety net |
Uncovering the hidden agenda: The RFC is often not the bleeding itself. Ask 「點解你揀今日嚟睇？」(Why did you come today specifically?) – the patient may have been triggered by a relative diagnosed with CRC, or has noticed weight loss, or read something online. This is where Concern lives.
| Domain | English Question | Cantonese Question | Why It Matters | If Positive Think Of |
|---|---|---|---|---|
| Onset/duration | When did the bleeding start? How often? | 「隻血幾時開始？幾密出一次？」 | Acute vs chronic guides urgency | Chronic intermittent → haemorrhoids, CRC; Acute massive → diverticular bleed |
| Colour | What colour is the blood? Bright red or dark? | 「血係鮮紅色定深色／暗紅色？」 | Fresh PR bleed: distal to splenic flexure; dark: proximal [1] | Bright red → anorectal; Dark/maroon → proximal colon; Black tarry → UGIB |
| Relationship to stool | Is the blood mixed in, on the surface, or dripping after? | 「血係混喺大便入面、包住外面、定係之後自己滴出嚟？」 | Mixed with stool → proximal to sigmoid; separate/after → outlet-type bleeding [2] | On paper/dripping → haemorrhoids, fissure; Mixed → CRC, IBD, diverticular |
| Amount | How much blood? Drops, streaks, or filling the bowl? | 「大概有幾多血？幾滴、幾條、定成個廁盤都係？」 | Quantifies severity | Large amount by itself → diverticular, angiodysplasia [2] |
| Pain on defecation | Do you have pain when you open your bowels? | 「去大便嗰陣有冇痛？」 | Fissure-in-ano: pain on defecation + fresh rectal bleeding [3] | Sharp pain at start → anal fissure; painless → haemorrhoids, CRC |
| Bowel habit change | Any change in frequency or consistency? | 「大便習慣有冇變？有冇時而肚瀉時而便秘？」 | Alternating diarrhoea and constipation → CRC [4] | CRC, IBD |
| Stool calibre | Are stools thinner than usual? | 「大便有冇變幼咗？」 | Pencil-thin stools → rectosigmoid CRC [4] | Left-sided / rectal CRC |
| Tenesmus | Do you feel you need to go but can't empty? | 「有冇覺得想去大便但去唔清？」 | Tenesmus: invariably present in lower rectal tumours [4] | Rectal cancer, proctitis |
| Mucus | Any mucus or slime in stool? | 「大便有冇黏液？」 | Bloody mucus → IBD or CRC | UC, rectal villous adenoma, CRC |
| Weight loss / appetite | Any unintentional weight loss? | 「有冇輕咗磅？食嘢有冇差咗？」 | Constitutional red flag for malignancy | CRC, IBD |
| Anaemic Sx | Dizziness, shortness of breath, fatigue? | 「有冇頭暈、氣促、成日覺得攰？」 | Chronic occult blood loss → Fe-deficiency anaemia | CRC (right-sided), angiodysplasia |
| Perianal Sx | Any perianal lump, itch, or prolapse? | 「有冇覺得肛門有嘢凸咗出嚟、痕癢？」 | Supports haemorrhoids | Haemorrhoids (prolapse), skin tag, perianal abscess |
| Drug Hx | Aspirin, NSAIDs, warfarin, DOACs? | 「有冇食阿士匹靈、薄血藥或者止痛藥？」 | Anticoagulants/antiplatelets worsen any GI bleed [5] | Drug-related bleeding, NSAID enteropathy |
| PMHx | Previous colonoscopy? IBD? Polyps? Liver disease? | 「之前有冇做過腸鏡、有冇腸炎、瘜肉？有冇肝病？」 | Prior polyps/IBD = higher CRC risk; liver disease → rectal varices | CRC surveillance, rectal varices |
| FHx | Any family history of bowel cancer, polyps, or IBD? | 「屋企人有冇人試過大腸癌、瘜肉或者腸炎？」 | Referral for colonoscopy if FHx CRC in 1st degree relative [6] | Hereditary CRC syndromes, FAP, Lynch |
| Social Hx | Smoking? Alcohol? Diet (fibre)? Occupation? | 「有冇食煙、飲酒？平時食多唔多菜？做咩工作？」 | Risk factors for CRC; functional impact | CRC risk, lifestyle counselling |
| Travel / sexual Hx | Recent travel? Receptive anal intercourse? | 「近排有冇去過旅行？」(If relevant:)「有冇肛交嘅習慣？」 | Infective colitis; STI-related proctitis | Amoebic dysentery, gonococcal/chlamydial proctitis |
| Constipation | Are you usually constipated? Straining? | 「平時有冇便秘？去大便使唔使好用力？」 | Straining → haemorrhoids & fissure risk | Haemorrhoids, fissure |
Case Report Form Answer Builder
Rectal bleeding × [duration].
High-yield points to capture:
- Onset, duration, frequency
- Colour (bright red / dark / mixed), amount
- Relationship to stool (on surface / mixed / after defecation / by itself)
- Associated Sx: pain on defecation, change in bowel habit, stool calibre, tenesmus, mucus
- Red flags: weight loss, appetite change, anaemic symptoms
- Relevant PMHx (previous colonoscopy, polyps, IBD), DHx (aspirin/NSAID/anticoagulant), FHx (CRC, polyps)
Likely RFC examples:
- "Patient concerned about the possibility of colorectal cancer"
- "Patient noticed increasing amount of rectal bleeding and is worried"
- "Prompted by a family member's recent diagnosis of bowel cancer"
Phrasing tip: The RFC is the patient's reason, not your diagnosis. Use patient-centred language. Often the hidden agenda IS the RFC.
| Example Wording | |
|---|---|
| Idea | "Patient thinks it might be haemorrhoids / is worried it could be cancer" |
| Concern | "Patient is worried about colorectal cancer, especially given family history of CRC" |
| Expectation | "Patient would like reassurance and investigation (e.g. colonoscopy) to rule out serious disease" |
In a primary care FM station with a middle-aged/young patient presenting with bright red painless outlet-type bleeding + straining/constipation history:
Most likely diagnosis: Haemorrhoids
Minimum supporting evidence: bright red blood separate from stool / on toilet paper, painless, history of constipation/straining, ± perianal lump/prolapse. Confirmed by proctoscopy.
If the stem features pain on defecation + fresh blood + constipation → consider Anal fissure as most likely.
If the stem has age > 50 + change in bowel habit + weight loss → consider Colorectal carcinoma.
| DDx | Key Discriminator |
|---|---|
| 1. Colorectal carcinoma | Age > 50, change in bowel habit, weight loss, iron-deficiency anaemia, FHx |
| 2. Anal fissure | Pain on defecation, history of constipation, visible fissure on inspection |
| 3. Inflammatory bowel disease (UC) | Young adult, bloody diarrhoea with mucus, extraintestinal manifestations |
(Alternatives depending on stem: diverticular disease in elderly, colorectal polyp, angiodysplasia)
| Domain | Problem |
|---|---|
| Biological | Rectal bleeding with risk of iron-deficiency anaemia; need to exclude colorectal malignancy |
| Psychological | Anxiety / fear of cancer (especially if FHx or media exposure) |
| Social | Impact on daily activities and work (e.g. embarrassment, frequent toilet visits, avoidance of social activities) |
| Diagnosis / DDx | Best Supporting Physical Sign | How to Elicit | Why It Supports This Diagnosis |
|---|---|---|---|
| Haemorrhoids (most likely) | Prolapsing haemorrhoidal cushions on proctoscopy / visible on inspection; bluish perianal swelling | DRE + proctoscopy; ask patient to bear down (Valsalva) – visible engorged vascular cushions at 3, 7, 11 o'clock positions [6] | Directly visualises the source; DRE to exclude other rectal lesions [6] |
| Anal fissure | Visible fissure on spreading the buttocks (usually posterior midline) [3] | Gently part the buttocks – look for linear tear; rectal examination and proctoscopy are painful and not indicated [3] | Pathognomonic finding; no instrumentation needed |
| Colorectal carcinoma | Palpable rectal mass on DRE; pallor (anaemia) [8] | Digital rectal examination – feel for fixed, irregular, hard mass; inspect conjunctivae for pallor | Low rectal tumours palpable on DRE; pallor from chronic occult blood loss |
| IBD (UC) | Tenderness over left iliac fossa; extraintestinal signs (erythema nodosum, oral ulcers, eye inflammation) | Abdominal palpation; general inspection | Supports colonic inflammation pattern |
| Diverticular disease | Usually no reliable physical sign in brief FM station | Abdominal exam may show LLQ tenderness if diverticulitis; often normal between episodes | Best exam clue: painless large-volume haematochezia in elderly → arrange colonoscopy |
Top Traps That Lose Marks
- Assuming all bright red PR blood = haemorrhoids – Always screen for CRC red flags (age, bowel habit change, weight loss, FHx). ALWAYS exclude other possible sources of PR bleeding [6].
- Forgetting to ask about drug history – Aspirin/NSAIDs/anticoagulants are high-yield.
- Missing the hidden agenda – The patient often fears cancer. If you don't ask ICE, you lose easy marks.
- Not asking about relationship of blood to stool – This is the single best discriminator between outlet and proximal bleeding [2].
- Forgetting UGIB can present as PR bleeding – 10–15% of severe haematochezia is from brisk UGIB [2]. Ask about haematemesis/coffee-ground vomiting.
- Performing DRE/proctoscopy on a patient with suspected fissure – Not indicated; diagnosis is by inspection (spreading buttocks) [3].
"Must Not Miss" Red Flags – Urgent Referral:
- Age > 50 with new PR bleeding + change in bowel habit → urgent colonoscopy referral [1]
- Unexplained iron-deficiency anaemia → colonoscopy
- Palpable rectal mass on DRE
- FHx of CRC in first-degree relative + PR bleeding → referral for colonoscopy [6]
- Haemodynamic instability (tachycardia, hypotension) → emergency
Minimal safe management / safety-net line for closing: 「我會安排你驗血睇下有冇貧血，同埋轉介你做腸鏡檢查排除其他問題。如果出血突然增多、頭暈企唔穩、或者肚好痛，要即刻去急症室。」 (I'll arrange blood tests for anaemia and refer you for colonoscopy. If bleeding suddenly increases, you feel faint, or have severe abdominal pain, go to A&E immediately.)
High Yield Summary
What to ASK: Colour, relationship of blood to stool, pain on defecation, bowel habit change, weight loss, drug history, family history of CRC, and ICE (especially cancer fear).
What to WRITE: Chief complaint with duration; relationship of blood to stool as key discriminator; RFC = usually cancer worry; most likely Dx usually haemorrhoids (unless red flags present); DDx must include CRC; biopsychosocial must include cancer anxiety and social impact.
What NOT to MISS: CRC red flags (age > 50 + change in bowel habit + weight loss + FHx); UGIB presenting as PR bleed; drug-related bleeding; fissure diagnosed by inspection only (no DRE).
Active Recall - Family Medicine Clinical Test
[1] Lecture slides: GC 186. Lower and diffuse abdominal painfresh blood in stool.pdf (p20 – intermittent PR bleeding investigation; CEA sensitivity ~30%) [2] Senior notes: Maksim Surgery Notes.pdf (p78 – LGIB history taking, relationship of blood to stool, DDx table); Ryan Ho Fundamentals.pdf (p282 – approach to LGIB, blood relationship to stool, 10-15% UGIB) [3] Lecture slides: GC 179. Anal pain perianal lesions and sepsis.pdf (p46 – fissure-in-ano: pain on defecation, diagnosis by inspection, DRE not indicated) [4] Senior notes: Ryan Ho GI.pdf (p165 – CRC clinical features: right side bleeds, left side blocks; tenesmus, pencil stools, alternating bowel habits) [5] Senior notes: Block A - Gastroenterology Interactive Tutorial.pdf (p1 – drug history importance, aspirin dilemma) [6] Senior notes: MBBS Final MB (Surgery) (Felix PY Lai).pdf (p748 – haemorrhoids: 4 degrees, ALWAYS exclude other sources, referral for colonoscopy indications; p691 – CRC diagnosis by DRE and pallor) [7] Senior notes: Block A - Coffee ground vomitus tarry stool upper GI bleeding.pdf (p8 – Heyde syndrome, angiodysplasia with aortic stenosis) [8] Senior notes: MBBS Final MB (Medicine) (Felix PY Lai).pdf (p894 – CRC physical exam: pallor, rectal mass on DRE; p653 – LGIB physical exam and biochemical tests)
Numbness / Tingling (paraesthesia)
Paraesthesia is an abnormal sensory perception of numbness, tingling, or "pins and needles" resulting from dysfunction or irritation of peripheral or central sensory neural pathways.
Others (In Murtagh)
Presenting complaints from Murtagh's General Practice beyond the HK primary care top 34 symptoms.