GC025 A Jaundiced And Incoherent Patient Liver Failure
Liver failure is a severe deterioration of hepatic function resulting in jaundice, hepatic encephalopathy (manifesting as confusion and incoherence), coagulopathy, and potential multiorgan dysfunction due to the liver's inability to perform its synthetic, metabolic, and detoxification functions.
A Jaundiced and Incoherent Patient: Liver Failure
This lecture by Prof. Wai-Kay Seto covers the clinical scenario of a patient presenting with jaundice and altered mental state — the classic presentation of liver failure with hepatic encephalopathy. It is one of the most commonly tested GC topics because it integrates pathophysiology, data interpretation (LFT, INR, ammonia), prognostic scoring (Child-Pugh, MELD, King's Criteria), and emergency management.
How the lecture fits in:
- GC 025 focuses on liver failure definitions, categorization, etiologies, prognostic factors, hepatic encephalopathy (precipitants, diagnosis, grading, management), coagulopathy, and ALF management.
- GC 026 (next lecture) covers the downstream complications of cirrhosis — ascites, SBP, varices, hepatorenal syndrome, portal hypertension, HCC.
- Together, GC 025 + 026 form the complete liver failure–cirrhosis–complications arc.
Learning Objectives (from slides):
- Define and categorize liver failure (ALF vs ACLF vs decompensated cirrhosis)
- Understand aetiologies of each category
- Know prognostic scoring systems and their limitations
- Understand the pathogenesis, grading, diagnosis, and management of hepatic encephalopathy
- Manage complications of liver failure (infections, coagulopathy, cerebral oedema)
- Know specific treatments for ALF causes (NAC, antivirals, activated charcoal)
1. Liver Failure: Definitions and Categorization
Liver failure is categorized into three types: Acute Liver Failure (ALF), Acute-on-Chronic Liver Failure (ACLF), and Decompensated Cirrhosis. [1]
This is the fundamental framework. Each category has different aetiologies, different prognostic tools, and different management strategies.
ALF = Development of severe acute liver injury with encephalopathy and impaired synthetic function (INR > 1.5) in a patient WITHOUT pre-existing cirrhosis/chronic liver disease. [1]
Why each criterion matters:
- Encephalopathy: proves the liver injury is severe enough to cause systemic toxicity (ammonia crossing the blood-brain barrier)
- INR > 1.5: proves synthetic function is critically impaired — the liver can no longer make clotting factors (especially Factor VII, half-life ~6 hours, making PT/INR the most sensitive acute marker of liver synthetic failure) [2]
- No pre-existing cirrhosis: distinguishes ALF from ACLF — this distinction matters for prognosis and transplant criteria
| Subtype | Jaundice-to-Encephalopathy Interval | Cerebral Oedema | INR | Bilirubin | Prognosis |
|---|---|---|---|---|---|
| Hyperacute | 0–1 week | Common | Very prolonged | Least raised | Moderate |
| Acute | 1–4 weeks | Common | Prolonged | Raised | Poor |
| Subacute | 4–26 weeks | Infrequent | Less prolonged | Raised | Poor |
Key Clinical Feature
Clinical features of ALF are "not obvious" [1] — the lecture emphasizes this because unlike decompensated cirrhosis with ascites, spider naevi, etc., ALF patients may look deceptively well early on. Jaundice may even be late, especially in paracetamol poisoning. The INR is your sentinel marker.
ACLF = Acute liver insult manifesting as jaundice and INR > 1.5, complicating within 4 weeks by ascites and/or encephalopathy, in patients with underlying chronic liver disease. [1]
Critical points:
- The chronic liver disease might be undiagnosed [1] — a patient may present for the first time with what appears to be ALF, but on investigation turns out to have pre-existing cirrhosis (e.g., splenomegaly on imaging, thrombocytopenia, stigmata of CLD on exam)
- 28-day mortality > 20% [1] — this is significantly worse than a typical cirrhosis decompensation
This is covered in detail in GC 026 but is mentioned here as the third category. It represents the development of symptomatic cirrhotic complications (ascites, variceal bleeding, HE, HRS, HCC) in a patient with known chronic liver disease.
2. Aetiologies of Liver Failure
Drug-related causes are the most important: [1]
- Paracetamol overdose
- Idiosyncratic drug reactions
- Herbal-related
Acute viral hepatitis (HAV / HEV / acute HBV)
Pregnancy-related causes (acute fatty liver of pregnancy / HELLP syndrome) — rare
Why paracetamol is #1: Paracetamol is metabolized by CYP2E1 to NAPQI, which is normally detoxified by glutathione. In overdose, glutathione is depleted → NAPQI accumulates → direct hepatocyte necrosis. This is dose-dependent and predictable, unlike idiosyncratic reactions.
Why herbal hepatotoxicity is highlighted: Prof. Seto dedicates multiple slides to this because it is extremely relevant in the Hong Kong clinical context.
In an acute HA Hospital study, HILI (Herb-Induced Liver Injury) accounted for 22% of in-patient acute hepatitis cases, equal to DILI (Drug-Induced Liver Injury) at 22%. [1]
- 102 types of hepatotoxic herbs have been reported in the literature [1]
- Herbal medications in tablet/capsule form are especially dangerous because patients may not consider them "medicines" and fail to report them
- Always ask about herbal medicine and health supplements in the drug history — this is a common exam pitfall
Exam Trap
When a question says "unremarkable past health" with ALF, and lists possible causes — think paracetamol overdose, acute viral hepatitis, or herbal/drug injury. Do NOT pick "red wine 1 day prior" (alcohol rarely causes acute liver failure from a single episode) or "atorvastatin" (statins cause hepatotoxicity very rarely). See 2022 MCQ Q39 [3] — the answer was acute hepatitis E, not red wine or atorvastatin.
HBV-related: [1]
- Severe exacerbation of HBV
- Immunosuppressive agents (steroids, rituximab etc.)
Infections:
- Superimposed HAV / HEV
- Other systemic infections (Pneumonia / UTI / soft tissue etc.)
External agents:
- Alcoholic hepatitis
- Hepatotoxic drugs / herbs
Why immunosuppressants matter: In an HBV carrier, immunosuppressive therapy (especially rituximab, which depletes B cells) can cause massive HBV reactivation. This is why all patients should be screened for HBV before chemotherapy/immunosuppression.
Specific "Hepatotoxic" Drugs: [1]
- Paracetamol (overdose)
- NSAIDs
- Statins (actually very rare)
- Anti-TB drugs (isoniazid, rifampicin, pyrazinamide)
- Other antimicrobials
- Anticonvulsants
- Rheumatological (methotrexate, azathioprine)
- Amiodarone
Why this list matters: In any exam question where a patient develops deranged LFTs, you MUST screen this list. Anti-TB drugs are a particularly common exam scenario (isoniazid is the main culprit for hepatotoxicity; rifampicin can cause cholestatic hepatitis).
High Yield
Statins are listed as hepatotoxic but the lecture explicitly notes this is "actually very rare." [1] This is an exam discriminator — examiners may try to trick you into blaming statins for liver failure when another cause is more likely.
Systemic effects include: [1]
- General non-specific malaise
- Encephalopathy
- Ascites
- Jaundice (usually late stage)
- Fetor hepaticus (usually late stage)
- Circulatory changes: ↑CO, ↓peripheral resistance, ↓renal blood flow
- N₂ metabolism: ↑NH₃, ↓urea, amino acid abnormalities, ↓albumin
- Skin changes due to vasodilatation: spider angioma, palmar erythema
- Endocrine changes: hypogonadism, hyperaldosteronism
- Defective coagulation, ↓platelet, ↑fibrinolysis
Why each effect occurs — from first principles:
| Effect | Mechanism |
|---|---|
| Encephalopathy | ↓hepatic detoxification of ammonia → crosses BBB → astrocyte swelling |
| Ascites | Portal hypertension + ↓albumin (↓oncotic pressure) + hyperaldosteronism (Na/H₂O retention) |
| Jaundice (late) | Hepatocyte damage → ↓conjugation/excretion of bilirubin |
| Fetor hepaticus | Dimethyl sulfide from failed hepatic metabolism — sweet, musty smell |
| ↑CO, ↓PVR | Splanchnic vasodilation from NO/prostacyclins → effective hypovolemia → compensatory ↑CO |
| ↓Renal blood flow | Splanchnic vasodilation → ↓effective circulating volume → renal vasoconstriction (hepatorenal syndrome) |
| ↑NH₃, ↓urea | Failed urea cycle — liver cannot convert ammonia to urea |
| ↓Albumin | ↓hepatic synthetic function (albumin half-life ~21 days, so late marker) |
| Spider angioma / Palmar erythema | Hyperestrogenism from ↓hepatic estrogen metabolism → arteriolar vasodilation |
| Hypogonadism | ↑estrogen, ↓testosterone from failed hepatic metabolism + ↑SHBG |
| Hyperaldosteronism | ↓hepatic clearance of aldosterone + RAAS activation from ↓effective circulating volume |
| Coagulopathy | ↓synthesis of clotting factors (II, V, VII, IX, X) + ↓platelet production (↓thrombopoietin) + hypersplenism |
Important Caveat from Lecture
Vibration-controlled transient elastography (FibroScan) is the non-invasive method to stage fibrosis. [1]
Why this matters: Liver biopsy is the gold standard for fibrosis staging but is invasive (bleeding risk, sampling error). FibroScan measures liver stiffness in kPa — higher values indicate more fibrosis. It is widely used in Hong Kong for HBV/MASLD patients.
5. Prognostic Scoring Systems
Child-Pugh Score: [1]
| Parameter | 1 point | 2 points | 3 points |
|---|---|---|---|
| Bilirubin (µmol/L) | < 34 | 34–51 | > 51 |
| Albumin (g/L) | > 35 | 28–35 | < 28 |
| INR | < 1.7 | 1.7–2.3 | > 2.3 |
| Ascites | None | Mild | Refractory |
| Encephalopathy | None | Gr 1–2 | Gr 3–4 |
| Class | Score | Significance |
|---|---|---|
| A | 5–6 | Compensated; good prognosis |
| B | 7–9 | Significant functional compromise |
| C | 10–15 | Decompensated; poor prognosis |
For bilirubin: 1 mg/dL = 17.1 µmol/L [1]
Disadvantages of Child-Pugh: [1]
- Limited discrimination — only 8 levels between Child B and C
- Same score for different values of bilirubin, albumin, PT
- Subjective assessment of ascites and encephalopathy
- Variability of PT and albumin across laboratories
- Albumin and PT measurements can be "manipulated" (e.g., albumin infusion, FFP transfusion)
Exam Intelligence
The Child-Pugh score is asked in virtually every exam cycle. The 2021 SAQ Q5 [5] directly asked students to "Name TWO prognostic models that can be used to grade the severity of cirrhosis" — answer: Child-Pugh score and MELD score. Know the components cold.
MELD = 3.8 × logₑ(bilirubin mg/dL) + 11.2 × logₑ(INR) + 9.6 × logₑ(creatinine mg/dL) + 6.4 [1]
Very good in prediction of 3-month mortality, useful to prioritize patients for liver transplant. [1]
Why MELD is better than Child-Pugh:
- Uses only objective laboratory values (bilirubin, INR, creatinine) — no subjective ascites/encephalopathy grading
- Continuous scale rather than categorical (A/B/C)
- Includes creatinine — critical because renal failure in liver disease (hepatorenal syndrome) is a major mortality driver
- Used worldwide for transplant allocation
MELD-Na (v2.0, 2016 onward) adds sodium to the formula, improving mortality prediction since hyponatraemia is an independent predictor of death in cirrhosis. [1]
Poor Prognostic Factors for ALF — Non-Paracetamol (King's Criteria): [1]
Irrespective of grade of encephalopathy:
- PT > 100 sec
OR 3 of the following:
- Age < 10 or > 40
- Duration of jaundice before encephalopathy > 7 days
- PT > 50 sec
- Bilirubin > 300 µmol/L
- Non-A Non-B, halothane, or idiosyncratic drug reaction
For Paracetamol Poisoning: [1]
- pH < 7.3
OR
- PT > 100 sec AND creatinine > 300 µmol/L in Grade III or IV encephalopathy
Why pH < 7.3: Lactic acidosis from massive hepatocyte necrosis → the liver can't clear lactate → systemic acidaemia. This signals irreversible damage.
High Yield
King's Criteria determine who needs emergency liver transplantation. Know both the paracetamol and non-paracetamol arms. The 2024 MCQ Q55 [6] tested indications for liver transplant — the correct answer was the patient with HBV developing bleeding tendency and HE after 2 weeks of jaundice (this is ACLF meeting transplant criteria).
Depends on 6 factors: [1]
- Cerebral: HE
- Respiration: SaO₂ / FiO₂
- Circulation: Need for vasopressor
- Liver: Bilirubin level
- Coagulation: INR level
- Kidney: Creatinine level
MELD score still useful. [1]
This reflects the CLIF-SOFA score framework — essentially an organ-failure assessment adapted for liver disease. The more organs failing, the worse the prognosis.
6. Complications of Liver Failure
Associated Complications of Liver Failure: [1]
- Infections
- Variceal bleeding
- Ascites / Spontaneous bacterial peritonitis
- Hepatorenal syndrome
- Hepatic encephalopathy
- (Coagulopathy)
Reticuloendothelial dysfunction and reduced opsonization [1] Very common (especially respiratory/urinary) Bacteraemia up to 25% in fulminant hepatic failure Staph, strep and GNR most common Broad-spectrum antibiotic prophylaxis recommended Risk of fungal infection — especially Candida [1]
Why liver failure patients are immunocompromised:
- The liver contains Kupffer cells (resident macrophages) which form part of the reticuloendothelial system → they clear bacteria from portal blood (especially gut-derived organisms). In liver failure, this function is impaired.
- Complement and opsonin production is reduced → bacteria are not tagged for destruction effectively
- Gut bacterial translocation is increased (disrupted gut barrier in portal hypertension)
Platelet dysfunction (quantitative and qualitative): [1]
- Platelet transfusion required if:
- Bleeding or invasive procedure and < 50 × 10⁹/L
- Prophylactically if < 20 × 10⁹/L
Prolongation of PT and INR: [1]
- PT/INR important prognostic indicators
- FFP only if active bleeding/invasive procedure
Why NOT to correct INR prophylactically: In liver failure, the "rebalanced haemostasis" concept applies — both procoagulant AND anticoagulant factors are reduced. The INR only measures procoagulant factors, so it overestimates bleeding risk. Giving FFP wastes resources, causes fluid overload, and obscures the prognostic value of INR.
7. Hepatic Encephalopathy (HE) — The Core Topic
This is the heart of the lecture and the reason for the "incoherent" in the title.
Pathogenesis: [1]
(I) ↑Arterial ammonia:
- ↓Ability of liver to detoxify NH₃ to urea
- ↑Cerebral metabolic rate and permeability to NH₃
- ↑NH₃ → astrocyte damage
(II) ↑Proinflammatory state → ↑Blood-brain barrier permeability
- ↑Cerebral cytokines (e.g., TNF, IL-1β) leads to HE
Others: ↑Cerebral lactate, manganese accumulation in basal ganglia, GABA receptor upregulation [1]
Explanation from first principles:
-
Ammonia source: Gut bacteria (urease-producing organisms like E. coli) break down urea and amino acids → produce ammonia. Protein breakdown also generates ammonia. Normally, the liver converts ammonia to urea via the urea cycle.
-
Failed detoxification: When the liver fails, ammonia accumulates in the blood (hyperammonaemia).
-
Brain effect: Ammonia crosses the blood-brain barrier. In astrocytes, it is converted to glutamine by glutamine synthetase. Glutamine is osmotically active → astrocyte swelling → cerebral oedema (especially in ALF). In chronic HE, low-grade swelling causes functional impairment without overt oedema.
-
Inflammation amplifies: Systemic inflammation (e.g., from infections) increases BBB permeability and enhances the neurotoxic effect of ammonia. This is why sepsis is one of the most important precipitants of HE.
-
GABA upregulation: Endogenous benzodiazepine-like substances accumulate → enhanced GABAergic inhibitory neurotransmission → sedation, coma.
This is one of the most commonly examined areas. The lecture divides precipitants into two mechanisms:
Mechanism 1: ↑Nitrogen products
↑N₂ products through: [1]
- Diet (high protein)
- Sepsis (catabolism → protein breakdown → ammonia)
- GI bleed (blood = high-protein load in gut → bacterial digestion → ammonia)
- Renal failure (↓renal ammonia excretion)
- Constipation (↑time for bacterial ammonia production in gut)
Mechanism 2: ↓Vascular volume → ↓O₂ delivery to liver
↓Vascular volume → ↓O₂ to liver, e.g.: [1]
- GI bleed
- Overdiuresis
- Excess paracentesis with inadequate albumin replacement
- Diarrhoea and vomiting
Other precipitants:
Sedatives [1] Electrolyte imbalance, especially ↓K [1] Acid-base imbalance [1] Artificial portal-systemic shunts (TIPS, surgery) [1]
Why hypokalaemia precipitates HE: Hypokalaemia causes intracellular alkalosis → alkalosis shifts the NH₄⁺/NH₃ equilibrium toward NH₃ (the unionized, lipid-soluble form that crosses the BBB). Also, hypokalaemia stimulates renal ammoniagenesis.
Why TIPS precipitates HE: TIPS (transjugular intrahepatic portosystemic shunt) creates a direct portal-systemic shunt → portal blood bypasses the liver entirely → ammonia-rich blood goes straight to the systemic circulation → brain. This is a known contraindication in patients with pre-existing HE [7].
Fulminant (Acute / ACLF): [1]
- Viral hepatitis
- Drugs (paracetamol, halothane, INAH)
- Metabolic (pregnancy, Reye syndrome, Wilson's disease)
- CVS (shock, heat stroke)
- Herbal medicines and health food products
| Grade | Consciousness/Intellect | Clinical Features | EEG |
|---|---|---|---|
| 0 | Normal | Nil | Normal |
| Subclinical (Minimal) | Normal | Nil except psychomotor testing abnormal | Normal |
| 1 | Inverted sleep pattern, forgetfulness, irritability | Tremor, apraxia, impaired handwriting | Slow 5 cps, triphasic waves |
| 2 | Lethargy, disorientation to time, personality change | Asterixis (flapping tremor), dysarthria | As above |
| 3 | Somnolence, confusion, disorientation to place | Hyperreflexia, rigidity, clonus | As above |
| 4 | Coma | Decerebrate posturing | Delta activity |
Cerebral oedema is uncommon in chronic HE but frequent in ALF. [1]
Why cerebral oedema differs between ALF and chronic HE: In chronic HE, astrocytes adapt by expelling osmolytes (myo-inositol, taurine) to compensate for glutamine accumulation. In ALF, the acute ammonia surge overwhelms these compensatory mechanisms → massive astrocyte swelling → cerebral oedema → raised ICP → herniation.
Confusion in cirrhosis — Differentials: [1]
- Drug- or alcohol-related
- Withdrawal state (e.g., delirium tremens)
- Head injuries
- CNS infections
- Systemic infections
- Metabolic disturbances (e.g., glucose)
- Psychiatric
- ...and more...
Clinical Pearl
Never assume confusion in a cirrhotic patient is HE — always exclude other causes first. A cirrhotic patient who drinks alcohol could be in delirium tremens (withdrawal). A patient who fell could have a subdural haematoma (especially with coagulopathy). Hypoglycaemia is common because the liver stores glycogen.
Diagnosis of HE: [1]
- Exclude other differentials
- Arterial ammonia:
- Normally 40% from bacterial action, 60% directly from protein breakdown
- Not always raised; may not correlate with severity of HE
- EEG abnormalities
- Other features:
- Fetor hepaticus
- Flapping tremor (asterixis)
- Psychometric tests: constructional apraxia (drawing a five-pointed star), number connection (Reitan's) test
Why ammonia doesn't always correlate with HE grade: Ammonia is just one neurotoxin. Inflammation, manganese, endogenous benzodiazepines, and other factors all contribute. Also, venous ammonia (often measured instead of arterial) is less accurate. However, a normal ammonia makes HE very unlikely.
Complex psychometric tests for "Minimal" HE include the Inhibitory Control Test, Critical Flicker Frequency, and smartphone apps. [1]
Minimal HE is the subclinical form — patients appear normal but have impaired psychomotor function. It affects driving ability and quality of life. It is detected only by specialized testing.
7.7 Management of HE
Identify precipitating factors and correct if correctable, e.g., sepsis — especially look for SBP, ↓K, withdraw sedatives. [1]
This is the most important step. HE is often triggered by a reversible insult. Look for and treat:
- Infection (do a diagnostic paracentesis for SBP!)
- GI bleeding
- Electrolyte/acid-base disturbance
- Constipation
- Sedative drugs
A. Lactulose (First-Line)
Lactulose: [1]
- Non-absorbable disaccharide
- Degraded in colon by urease-negative lactobacilli
- Mechanism of action:
- Osmotic laxative (reduces transit time → less time for ammonia production)
- ↓Colonic pH:
- Inhibit urease-producing bacteria, especially E. coli
- Trap luminal NH₃ → NH₄⁺ (ionized form can't be absorbed)
- Draws NH₃ from mucosal blood to gut
- Target: 2–3 soft stools per day
- Can give enema form (useful in obtunded patients who can't take oral)
Why the pH mechanism is brilliant: Lowering colonic pH shifts the ammonia equilibrium:
- NH₃ (gas, absorbable) ⇌ NH₄⁺ (ion, not absorbed)
- Acidic environment favours NH₄⁺ → ammonia is trapped in the gut lumen → excreted in stool
B. Rifaximin (Second-Line / Adjunctive)
Rifaximin: [1]
- Non-absorbable antibiotic
- Alteration of colonic flora (especially urease-producing bacteria)
- Combined use with lactulose effective
- Also effective in reducing recurrence of HE
- Neomycin: potential nephrotoxicity/ototoxicity, no longer recommended
The landmark Bass et al. NEJM 2010 trial [1] showed rifaximin significantly reduced HE recurrence. It is now standard for secondary prevention of HE.
C. Fecal Microbiota Transplantation (FMT)
"Time will tell..." [1] — still experimental, not standard care.
Diet: [1]
- Avoid dietary protein restriction (except in active GI bleeding)
- Recommended protein intake: 40–60 g/day
- Dietitian input important
Important Paradigm Shift
Old teaching said "restrict protein in HE." This is WRONG and harmful. Protein restriction → sarcopenia → worse outcomes. The lecture explicitly states: "Avoid dietary protein restriction." [1] Only restrict temporarily during active GI bleeding (when gut is full of protein from blood).
Branch-Chained Amino Acids (BCAA): [1]
- Detoxify ammonia via production of glutamine
- Also function as nutritional supplement
- Mainly in protein-intolerant patients
L-Ornithine-L-Aspartate (LOLA): [1]
- Converts L-ornithine to glutamate in muscle
- Conversion uses ammonia to produce glutamine
Why these are "moderate effect only": They work by providing substrates for glutamine synthesis in muscle (an alternative site for ammonia detoxification when the liver fails). However, the glutamine produced can itself be converted back to ammonia in the kidney, limiting the net benefit.
ALF Management: [1]
1. Supportive (standard ICU care)
2. Identify and remove/treat the insult:
- HBV → Treat HBV (tenofovir/entecavir)
- Paracetamol → N-acetylcysteine (NAC)
- Mushroom → Activated charcoal
3. Manage complications:
- Infections
- Hepatic encephalopathy
- Increased ICP / Cerebral oedema
- Renal failure
- Metabolic complications: ↓Na, ↓glucose
4. High-volume plasma exchange*
5. Liver transplantation
Unproven/Experimental: [1]
- Liver support systems (e.g., MARS)
- N-acetylcysteine for all aetiologies
- G-CSF
- Plasmapheresis (high volume)
Why NAC works in paracetamol overdose: NAC is a precursor of glutathione. By replenishing glutathione stores, it enables detoxification of NAPQI, the toxic metabolite of paracetamol.
Why activated charcoal for mushroom poisoning: Amatoxin (from Amanita phalloides) undergoes enterohepatic circulation. Activated charcoal in the gut binds the toxin and interrupts recirculation. Must be given early.
Why plasma exchange: Removes toxins, cytokines, and damage-associated molecular patterns (DAMPs) from the blood, providing a "bridge" to transplant or recovery. Recent evidence (Larsen et al., J Hepatol 2016) suggests benefit in ALF.
9. Integration with Related Material
| Pattern | Predominant Elevation | Think... |
|---|---|---|
| Hepatocellular | AST, ALT ↑↑↑ | Hepatitis (viral, drug, autoimmune, ischaemic) |
| Cholestatic | ALP, GGT ↑↑↑, ± bilirubin | Obstruction (stone, tumour), PBC, PSC, drugs |
| Mixed | Both elevated | Drug reaction, infiltrative disease |
| Isolated ↑bilirubin | Bilirubin ↑, rest normal | Haemolysis, Gilbert's, Crigler-Najjar |
AST:ALT ratio clues [8]:
- AST:ALT > 2:1 → Alcoholic hepatitis
- AST:ALT ~1:1 with very high levels + ↑LDH → Ischaemic hepatitis
- ALT > AST → Viral hepatitis
Both cause prolonged PT. The parenteral vitamin K test differentiates:
- If PT corrects after IV vitamin K → cholestasis (the "factory" is fine, just lacking raw material)
- If PT does NOT correct → hepatocellular failure (the "factory" is broken)
The answer was livedoid reticularis (a vascular pattern from vasculopathy/thrombotic disorders, not CLD). The CLD stigmata are: jaundice, palmar erythema, spider angioma, Dupuytren's contracture, gynaecomastia, testicular atrophy, etc.
10. Likely Exam Questions
Q1: A 50-year-old HBV carrier presents with jaundice and confusion 2 weeks after starting rituximab. INR 2.5, bilirubin 280 µmol/L. What is the most likely diagnosis?
- Answer: Acute-on-chronic liver failure due to HBV reactivation from immunosuppression
Q2: A patient with cirrhosis develops confusion. Which investigation is most important to exclude a precipitant?
- Answer: Diagnostic paracentesis (to exclude SBP) — also check for infection, electrolytes, GI bleeding
Q3: Which of the following is NOT a component of the Child-Pugh score?
- A. Creatinine ← This is the answer (creatinine is in MELD, not Child-Pugh)
- B. Albumin
- C. Ascites
- D. Encephalopathy
Q4: A 33-year-old woman with no past history presents with jaundice, confusion, AST > 3000, INR 4.8. List the King's College Criteria for non-paracetamol ALF that indicate need for liver transplantation. (Reference: 2022 MCQ Q39 [3])
Markscheme points:
- PT > 100 sec (irrespective of HE grade)
- OR 3 of: age < 10 or > 40; jaundice-to-encephalopathy > 7 days; PT > 50 sec; bilirubin > 300 µmol/L; non-A non-B/halothane/idiosyncratic drug
Q5: List 4 precipitating factors for hepatic encephalopathy in a cirrhotic patient. (Reference: 2021 SAQ Q5 [5])
Markscheme points (any 4):
- Infection/sepsis (especially SBP)
- GI bleeding
- Constipation
- Electrolyte imbalance (↓K)
- Sedatives/opioids
- Overdiuresis/excess paracentesis without albumin replacement
- Renal failure
- High protein diet
- TIPS
Q6: Describe the mechanism of action of lactulose in treating hepatic encephalopathy.
Markscheme points:
- Osmotic laxative → ↓transit time → ↓ammonia absorption
- ↓Colonic pH → inhibits urease-producing bacteria → ↓ammonia production
- ↓Colonic pH → traps NH₃ as NH₄⁺ → prevents absorption → draws ammonia from blood into gut lumen
- Target: 2–3 soft stools/day
| Trap | Why Students Fall for It | Correct Approach |
|---|---|---|
| Blaming statins for ALF | Statins are "hepatotoxic drugs" | Lecture says "actually very rare" — look for paracetamol, herbs, viral causes first |
| Restricting protein in HE | Old teaching | Current: avoid restriction, recommend 40–60 g/day |
| Using neomycin for HE | It was used historically | Nephrotoxic/ototoxic — no longer recommended; use rifaximin |
| Correcting INR prophylactically in liver failure | INR is prolonged so "must correct" | Only correct for active bleeding/invasive procedures — otherwise loses prognostic value |
| Assuming ammonia always correlates with HE grade | Ammonia is the main mechanism | Ammonia may be normal in HE; not always raised; may not correlate |
| Choosing "alcohol" as cause of ALF from a single binge | Alcohol causes chronic liver disease | A single binge rarely causes ALF; alcoholic hepatitis is usually ACLF |
| Confusing Child-Pugh and MELD components | Both are scoring systems | Child-Pugh: Bilirubin, Albumin, INR, Ascites, Encephalopathy; MELD: Bilirubin, INR, Creatinine |
| Forgetting TIPS as HE precipitant | TIPS is a treatment for varices/ascites | TIPS creates a portosystemic shunt → bypasses liver → ↑ammonia to brain |
High Yield Summary
Liver failure is categorized into ALF (no prior liver disease, INR > 1.5, encephalopathy), ACLF (acute insult + chronic liver disease, INR > 1.5, ascites/encephalopathy within 4 weeks), and decompensated cirrhosis. Top causes of ALF: paracetamol, viral hepatitis, herbs/drugs. Prognostic tools: Child-Pugh (5 parameters: Bilirubin, Albumin, INR, Ascites, Encephalopathy) and MELD (Bilirubin, INR, Creatinine) for cirrhosis; King's Criteria for ALF transplant decisions. Hepatic encephalopathy is driven by ammonia and inflammation — precipitated by sepsis (especially SBP), GI bleed, constipation, ↓K, sedatives, TIPS. Grade 0–4. Diagnosis: exclude differentials, arterial ammonia (imperfect), flapping tremor, psychometric tests. Treatment: correct precipitants first, then lactulose (target 2–3 soft stools/day; lowers pH, traps NH₃ as NH₄⁺) + rifaximin (alters colonic flora). Do NOT restrict protein (40–60 g/day). For ALF: ICU care, treat cause (NAC for paracetamol, antivirals for HBV), manage complications (infections, coagulopathy, cerebral oedema), consider transplant if King's criteria met.
Active Recall - Liver Failure & Hepatic Encephalopathy
[1] Lecture slides: GC 025. A jaundiced and incoherent patient liver failure.pdf (all pages) [2] Senior notes: Block A - Introduction to GI_Hepatology investigations (LFT, Endoscopy).pdf (pp. 8, 14) [3] Past papers: 2022 Fourth Summative MCQ.pdf (Q39, p. 15) [4] Senior notes: Block A - Jaundice after raw oysters_ acute hepatitis.pdf (p. 2) [5] Past papers: 2021 Fourth Summative SAQ.pdf (Q5, p. 6) [6] Past papers: 2024 Fourth Summative MCQ.pdf (Q11 p. 5, Q55 p. 21) [7] Senior notes: Block A - Gastrointestinal Data Interpretation.pdf (p. 6) [8] Senior notes: Ryan Ho GI.pdf (pp. 204, 206, 208)
GC024 A Fatigued And Sleepy Patient
A clinical presentation in which persistent fatigue and excessive sleepiness suggest underlying conditions such as obstructive sleep apnea, hypothyroidism, anemia, or other systemic disorders requiring systematic evaluation.
GC026 Abdominal Distension: Ascites And Cirrhosis
Abdominal distension resulting from ascites, the pathological accumulation of fluid in the peritoneal cavity, most commonly caused by hepatic cirrhosis with portal hypertension and splanchnic vasodilation.