MBBS SAQ · Gastroenterology / Hepatology
Acute liver failure — paracetamol overdose, King's College Criteria and emergency management
A final-prof / NEET-PG SAQ on paracetamol-induced acute liver failure — diagnosis of ALF (the defining triad), early NAC, King's College Criteria for transplant (this patient meets them), neuroprotection for grade III encephalopathy, and the five-priority ICU bundle.
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Question
A 22-year-old woman is brought to the emergency department 36 hours after taking 30 g of paracetamol in a deliberate overdose. She is drowsy (GCS 13), jaundiced and has vomited twice. Bloods: INR 7.2, arterial pH 7.25, lactate 5.5 mmol/L, creatinine 340 micromol/L, ALT 8600 IU/L, glucose 2.8 mmol/L. Discuss your immediate assessment, the criteria that determine emergency liver transplantation, and your stepwise management.
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Diagnosis: acute liver failure due to paracetamol overdose. The defining triad is present — severe acute liver injury (ALT 8600, jaundice), coagulopathy (INR 7.2, well over 1.5) and encephalopathy (drowsy, GCS 13 = grade III), all within 26 weeks, in a patient without pre-existing liver disease. The hyperacute pattern (jaundice to encephalopathy under 7 days) and the history of a large paracetamol ingestion make paracetamol the cause.[1][3]
Immediate assessment — ABCDE. Airway at risk with grade III encephalopathy — intubate early to protect the airway and for ICP control. Breathing — high-flow oxygen. Circulation — two large-bore cannulae, IV access, group and save, treat hypotension. Disability — check and correct glucose (2.8 mmol/L, give 50 percent dextrose). Exposure — full sets, collateral history confirming timing/dose of overdose.[3]
Emergency liver transplantation — King's College Criteria. Apply the paracetamol King's College Criteria (O'Grady 1989):[2]
- Arterial pH below 7.3 after adequate fluid resuscitation (this patient's pH is 7.25 — criteria met), OR
- All three of INR over 6.5 (hers 7.2 — yes), creatinine over 300 micromol/L (hers 340 — yes) and grade III–IV encephalopathy (yes — all three also met).
- The arterial lactate (5.5 mmol/L, well over 3.5) is an additional adverse marker.
This patient meets King's College Criteria on both arms — refer to the liver transplant centre immediately. Do not wait for organ failure to refer.[1][2]
Stepwise management (the five priorities).[1][5]
- ICU + identify/treat the cause. Start intravenous N-acetylcysteine immediately — 150 mg/kg over 1 h, then 50 mg/kg over 4 h, then 100 mg/kg over 16 h — even though more than 24 h have passed; NAC is given to all paracetamol-induced ALF. Send a paracetamol level and full aetiological screen.
- Encephalopathy / cerebral oedema. Head of bed 30 degrees; intubate and ventilate to normocapnia; hypertonic saline to a sodium of 145–155 mmol/L; mannitol 0.5 g/kg bolus for rising ICP; continuous renal replacement therapy helps control ammonia; avoid hypotension, hypoxia and hypoglycaemia.
- Coagulopathy / hypoglycaemia. Correct glucose and keep it above 7 mmol/L; give vitamin K 5–10 mg; give fresh frozen plasma only if bleeding or before a procedure — do NOT correct the INR prophylactically, as it is the key prognostic and transplant marker.
- Circulation / infection / renal. Noradrenaline first-line for vasoplegic hypotension; albumin resuscitation; surveillance cultures and broad-spectrum antibiotic/antifungal cover per protocol; continuous renal replacement therapy for the renal failure and to lower ammonia.
- Transplant. Early transfer for emergency liver transplantation — the only definitive treatment when King's College Criteria are met.
Common errors
- Not giving N-acetylcysteine because more than 8 hours have elapsed — NAC is given to ALL paracetamol-induced ALF regardless of timing.
- Prophylactically correcting the INR with FFP — this erases the key prognostic marker and the transplant trigger; correct only if bleeding or before procedures.
- Late referral for transplant — refer the moment King's College Criteria are met, not when multi-organ failure develops.
- Not intubating grade III–IV encephalopathy — airway protection and ICP control require intubation.
- Fluid overload — worsens cerebral oedema; resuscitate with albumin, target sodium 145–155 mmol/L.
- Missing hypoglycaemia — correct and monitor hourly; hypoglycaemia worsens encephalopathy and mimics cerebral oedema.
- Forgetting psychosocial care — once medically stable, mental-health assessment and safeguarding are essential after deliberate overdose.
Examiner notes
- The exam wants the structured approach: recognise the defining triad of ALF → early NAC → reproduce King's College Criteria verbatim and apply them → the five-priority ICU bundle → early transplant referral.
- Reproduce King's College paracetamol criteria in full (pH below 7.3, OR all three of INR over 6.5, creatinine over 300, grade III–IV encephalopathy) to score full marks.[2]
- A strong candidate states that NAC improves transplant-free survival even in non-paracetamol ALF (Lee et al, Gastroenterology 2009) and that death in ALF is from cerebral oedema, sepsis and multi-organ failure — not from the liver itself.[5][1]
References4ShowHide
- [1]Stravitz RT, Lee WM. Acute liver failure. Lancet, 2019.PMID 31498101
- [2]O'Grady JG, Alexander GJ, Hayllar KM, et al. Early indicators of prognosis in fulminant hepatic failure. Gastroenterology, 1989.PMID 2490426
- [3]Bernal W, Wendon J. Acute liver failure. N Engl J Med, 2013.PMID 24369077
- [5]Lee WM, Hynan LS, Rossaro L, et al. Intravenous N-acetylcysteine improves transplant-free survival in early stage non-acetaminophen acute liver failure. Gastroenterology, 2009.PMID 19524577