Fulminant hepatic failure
Fulminant hepatic failure (FHF) is defined as encephalopathy due to massive hepatic necrosis within 8 weeks of the onset of the primary illness, with no evidence of previous liver disease. This excludes subacute hepatic necrosis, acute-on-chronic hepatic failure and chronic hepatic encephalopathy. It is a relatively rare disease.
The diagnosis can be difficult especially in the early stages. Patients usually do not have signs of chronic liver failure such as spider naevi and palmar erythema.
Encephalopathy is the hallmark of this disease and disturbance in the level of consciousness may be the only presenting feature.
The clinical course may be over hours or days.
Encephalopathy: Many factors have been implicated but as yet no definite cause of the encephalopathy has been found. Ammonia, free fatty acids, phenols, bilirubin, bile acids, mercaptans, false neurotransmitters, benzodiazepine analogues and γ-aminobutyric acid (GABA) are some of the implicated compounds.
Stages of encephalopathy:
There are no specific clinical or EEG features that can be used to differentiate this encephalopathy from those associated with other metabolic disturbances.