Examqo › Examqo library › Internal medicine › Gastroenterology and hepatology · IMLE
Acute liver failure
Acute liver failure is an INR of 1.5 or more with encephalopathy in a patient without previous liver disease; N-acetylcysteine is started (certainly in paracetamol poisoning), the patient is transferred early to a transplant centre, and the INR is not corrected routinely because it is a prognostic marker.
Why it matters in the exam
The question presents a young person with jaundice, confusion and transaminases in the thousands, and asks for the cause and the next step. The commonest cause in the West is paracetamol (sometimes deliberate overdose, sometimes repeated "therapeutic" doses in a drinker or a malnourished person); then viruses (A, B, E), idiosyncratic drugs, autoimmune hepatitis, Wilson disease, Budd-Chiari, ischaemia, acute fatty liver of pregnancy and HELLP, and poisonous mushrooms. In paracetamol poisoning the nomogram is used only when the ingestion was single and its time is known; in any doubt, N-acetylcysteine is given.
Treatment is intensive care: monitoring glucose (hypoglycaemia is common), infections, kidney function and intracranial pressure — cerebral oedema appears mainly with grade III–IV encephalopathy, where sodium is kept high-normal and unnecessary sedatives are avoided. The INR is not corrected with plasma without bleeding or a procedure, because it is used to decide on transplant. The King's College criteria for paracetamol: pH below 7.3 after fluid resuscitation, or the combination of INR above 6.5, creatinine above 3.4 mg/dL and grade III–IV encephalopathy. N-acetylcysteine also helps non-paracetamol liver failure at early encephalopathy grades.
Key points
- Definition: INR 1.5 or more + encephalopathy, no previous liver disease.
- Paracetamol is the common cause; N-acetylcysteine at once.
- Early transfer to a transplant centre.
- King's College: pH below 7.3, or INR above 6.5 + creatinine above 3.4 mg/dL + grade III–IV encephalopathy.
- Do not correct INR without bleeding; monitor glucose and intracranial pressure.
Summary table
| Topic | Finding | Action | Exam note |
|---|---|---|---|
| Definition | INR 1.5 or more + encephalopathy, no previous liver disease | Transfer to a transplant centre | Develops within weeks |
| Paracetamol | The commonest cause in the West | N-acetylcysteine at once | Nomogram only for a single ingestion with known time |
| Other causes | A, B, E; drugs; autoimmune; Wilson; Budd-Chiari; pregnancy | Focused work-up | E is dangerous in pregnancy |
| King's College (paracetamol) | pH below 7.3; or INR above 6.5 + creatinine above 3.4 mg/dL + grade III–IV encephalopathy | Transplant listing | High lactate adds risk |
| Supportive care | Glucose, infection, kidneys, intracranial pressure | Intensive care | Cerebral oedema at grade III–IV |
| Clotting | High INR | Do not correct routinely | Only for bleeding or before a procedure |
In the full version for subscribers
- A simple algorithm
- Memory aid
- Exam traps
- 5 review cards
- Enough for IMLE
The full version is open to subscribers of: Medical licensing exam (IMLE), Internal medicine, Emergency medicine, Dermatology and venereology, ENT and head and neck surgery, Forensic medicine, Occupational medicine, Pediatric surgery.
Subscriber? Read the full topic Plans and prices 25 free questions
Sources
- EASL Clinical Practical Guidelines on the management of acute (fulminant) liver failure, 2017 — Definition, causes, intensive care and transplant criteria
- Harrison's Principles of Internal Medicine, 21st edition (2022) — Acute Liver Failure; Acetaminophen Hepatotoxicity
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.