Acute Liver Failure

Basics

A set of criteria has been proposed to diagnose pediatric acute liver failure (ALF).
- Biochemical evidence of liver injury due to rapid loss of hepatocyte function
- No previous history of chronic liver disease
- Coagulopathy not responsive to vitamin K administration
- International normalized ratio (INR) >1.5 in presence of encephalopathy or INR >2 without encephalopathy
In older children, in whom hepatic encephalopathy can be more easily assessed, ALF may more simply be defined as follows:
- Onset of encephalopathy <8 weeks after the onset of symptoms referable to liver dysfunction in a patient without preexisting liver disease

Exact frequency of ALF in children is unknown but accounts for 10–15% of pediatric liver transplants in the United States annually.
In infants and children <3 years of age, indeterminate and metabolic etiologies predominate.
In older children, drug-induced toxicity (especially acetaminophen), autoimmune hepatitis become more common.
Infectious etiologies (e.g., viral hepatitis) vary in prevalence based on geographic region.

Hepatocellular necrosis leads to release of growth factors that promote hepatic regeneration.
Hepatic failure may become irreversible if:
- The initial insult overcomes the liver’s regenerative capacity.
- The offending agent or derangement is not eliminated or corrected.
- Secondary complications, such as shock or disseminated intravascular coagulation, lead to further injury.

The major causes of ALF can be grouped into the following broad categories:

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