Acute liver failure (ALF) is an uncommon but devastating illness caused by acute loss of hepatocellular function secondary to hepatocellular injury or death.
ALF is an uncommon condition. In the UK there are approximately 400 cases per year, of which up to 70% of these are secondary to paracetamol (acetaminophen) overdose.
Definition
Acute liver failure is defined by:
- Evidence of coagulation abnormality (Usually an INR greater than or equal to 1.5)
- Plus any degree of mental alteration (encephalopathy)
- in a patient without pre-existing cirrhosis
- and with an illness of less than or equal to 26 weeks duration
Classification
The most widely used classification is based on the speed of onset of encephalopathy from when the patient becomes symptomatic. These definitions have prognostic implications.
| Classification | Transplant-free survival | Likely aetiology |
|---|---|---|
| Hyperacute (0-7 days) | 30% | Paracetamol, ischaemia |
| Acute (7-28 days) | 33% | Viral |
| Subacute (>28 days) | 14% | Non-paracetamol drugs |
King’s College Criteria
Paracetamol-induced liver failure
- Arterial pH < 7.30
Or all three of (within the same 24h period):
- INR > 6.5 (PT > 100 sec)
- Creatinine > 300 µmol/L
- Grade III or IV hepatic encephalopathy
Non-paracetamol-induced liver failure
- INR > 6.5 (PT > 100 sec)
Or any three or more of:
- Age <11 or >40 years
- Etiology: non-A/non-B hepatitis, drug-induced
- Duration of jaundice to hepatic encephalopathy (HE) >7 days
- INR > 3.5 (Prothrombin time >50 sec)
- Serum bilirubin >300 µmol/L