Acute liver failure (ALF) is defined as the appearance of encephalopathy together with coagulopathy, usually an international normalized ratio (INR)
≥1.5, in a patient who has no previous history of liver disease and who has had an illness of <26 weeks' duration.
- Drug-related toxicity accounts for more than half of the cases of ALF in the United States. Of these drug-related cases, more than 80% are the result of acetaminophen ingestion.
- The natural history of adult ALF in the United States is one of spontaneous recovery in approximately 45% of patients, liver transplantation in 25%, and death without transplantation in 30%.
- The most serious, and often the proximate cause of death, is acute cerebral edema and intracranial hypertension (Table 45-4: General Measures to Reduce Cerebral Edema).
- Coagulopathy is a necessary finding for the diagnosis of ALF; however, clinically significant spontaneous bleeding is uncommon. Correction of thrombocytopenia to ≥50,000/mm3 and INR to ≤1.5 are suggested for the bleeding patient or the patient about to undergo an invasive procedure.
- Hypotension in ALF may be the result of several days of gastrointestinal losses, poor intake, or myocardial dysfunction but likely includes a component of decreased arterial tone as liver necrosis progresses.
- Vasopressors (norepinephrine, dopamine) may be used to treat either systemic hypotension or to maintain an adequate cerebral perfusion pressure.
- The use of arginine vasopressin or its analogs cannot be recommended because there is evidence that their use is associated with increases in intrahepatic cholestasis of pregnancy (ICP).