Chapter 30

Acute liver failure (ALF) is a rare but devastating result of hepatic necrosis in previously healthy individuals. Hepatic function rapidly declines within days to weeks and is often complicated by coagulopathy, hepatic encephalopathy (HE), hypoglycemia, acute renal failure, sepsis, and gastrointestinal bleeding. These complications can lead to death with mortality rates up to 40% in the United States.1

Children who develop ALF by definition have no previous history of liver disease. Traditionally, the criteria for defining ALF included the development of HE within 8–12 weeks of the first signs of illness. This definition has since been revised due to the difficultly in assessing HE in infants and younger children and the variability in initial presentation.

In 1999 the Pediatric Acute Liver Failure Study Group (PALFSG) was formed to better understand the pathogenesis and treatment of ALF. An important initial task included defining ALF in childhood and creating a scale to assess encephalopathy in children younger than 4 years of age. The definition of ALF in children included four major criteria: (1) the absence of prior liver disease; (2) serum biochemical markers showing evidence of acute liver injury; (3) coagulopathy not correctable with vitamin K administration; (4) international normalized ratio (INR) ≥1.5 in the setting of HE or ≥2.0 without HE.2 A scale was created to help assess HE in children under the age of 4 years (Table 30–1).

Table 30–1. Staging of Hepatic Encephalopathy

The overall incidence of pediatric ALF is low, but the rate of devastating complications and mortality is high. The primary causes of ALF in children include viral hepatitis, drug-induced liver failure, metabolic causes, autoimmune disease, and idiopathic causes. Approximately 50% of cases of pediatric ALF have no known cause.2 Regardless of the cause, ALF is a medical emergency and early recognition affects outcome. Prior to liver transplantation becoming an available treatment option, death rates approached 100%.1 Currently, short-term survival with liver transplantation is >65%.3

The pathologic features of ALF include rapid and massive hepatocyte death, with failure of the remaining hepatocytes to regenerate. The mechanism of this severe hepatic necrosis is unknown. Although approximately 50% of cases ...

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