Acute Liver Failure (ALF)

Definition, etiology-specific treatment (APAP, HBV, mushroom), system-based ICU management, and LT prognostication using KCC and MELD.

📖 4 Sections⏱ ~30 min✅ 4-question quiz

Definition & Etiology

ALF criteria, causes, ALF vs ACLF

Acute Liver Failure (ALF)

ALF is a rare, life-threatening, potentially reversible condition. Key definition: acute liver injury + INR >1.5 + hepatic encephalopathy in a patient with NO pre-existing liver disease, occurring within 26 weeks of illness onset.

Acute Liver Injury

Elevated LFTs only. INR normal. No HE. Usually benign, reversible.

Severe Acute Liver Injury

ALT elevation + coagulopathy (INR >1.5). No HE yet. May progress.

Acute Liver FAILURE

ALI + INR >1.5 + Hepatic Encephalopathy. ICU-level care required.

Common Etiologies in the US

#1 — Acetaminophen (APAP) toxicity (~50%)

Intentional overdose or inadvertent supratherapeutic dosing. Most common in US.

Drug-Induced Liver Injury (DILI)

Antibiotics (amoxicillin/clavulanate), anticonvulsants, herbal/dietary supplements.

Hepatitis B Virus (HBV)

Acute HBV or reactivation (especially in immunosuppressed patients).

Autoimmune Hepatitis (AIH)

Can present acutely. Biopsy-confirmed. May respond to corticosteroids.

Ischemic Hepatitis

Shock liver — cardiac failure, hypoperfusion. Dramatic transaminase elevation.

Mushroom Poisoning (Amanita)

Amatoxin — inhibits RNA polymerase II. Delayed onset 6–24h after ingestion.

ALF vs ACLF

Patients with ALF are typically young with NO prior liver disease; they develop cerebral edema with elevated ICP. Patients with ACLF have underlying chronic liver disease, are typically older, and develop HE that responds to lactulose/rifaximin. RENAL failure pattern also differs: ALF → hypoperfusion/ATN; ACLF → hepatorenal syndrome.

Shingina A et al. ACG Clinical Guideline: Acute Liver Failure. Am J Gastroenterol. 2023;118:1128–1153.