Acute liver failure is a multisystem critical illness. It is defined by acute liver injury, coagulopathy, and encephalopathy in a patient without preexisting cirrhosis. The liver fails, but the brain, kidneys, circulation, lungs, and immune system are all affected.
Encephalopathy is central because it signals impaired hepatic detoxification and increased risk of cerebral edema. Ammonia contributes to astrocyte swelling, altered neurotransmission, and cerebral edema risk. Severe hyperammonemia is especially concerning. Hypoglycemia can occur because the liver cannot maintain normal glycogenolysis and gluconeogenesis.
Coagulopathy occurs because the liver produces many clotting factors, but INR does not perfectly predict bleeding risk. Acute liver failure is a rebalanced but fragile hemostatic state. The kidneys may fail from shock, inflammation, hepatorenal physiology, toxins, or multi-organ failure. Infection risk is high because immune dysfunction develops.