HEPATITIS

DEF: Infectious or idiopathic inflammation of the liver.
ETIOL: Neonatal hepatitis can be caused by a variety of infectious agents, including cytomegalovirus (CMV), rubella, reovirus type 3, herpes simplex, herpes zoster, herpesvirus type 6, adenovirus, enteroviruses, parvovirus B19, hepatitis viruses, human immunodeficiency virus, bacterial sepsis (gram-negative rods, staphylococci, streptococci), syphilis, listeriosis, tuberculosis, and toxoplasmosis. Idiopathic neonatal hepatitis describes neonatal cholestatic liver disease for which all other known causes, including metabolic, infectious, and extrahepatic obstruction, have been ruled out. The incidence of idiopathic neonatal hepatitis is 1 in 5,000 births and accounts for 50% of cases of prolonged neonatal jaundice.
CLIN/STUDIES/TX: The history should focus on maternal infection during pregnancy and delivery and family history of pediatric liver disease. The major types of neonatal hepatitis are as follows:
Idiopathic: More common in premature or small-for-gestational-age (SGA) infants. Fifty percent have jaundice in the first week of life. Hepatosplenomegaly is common. One-third of these infants fail to thrive. Acholic stools may or may not be present. Radionuclide hepatobiliary imaging shows slow liver uptake with positive intestinal excretion. Liver histology is variable, with inflammation, hepatocellular unrest, multinucleated giant cells, and extramedullary hematopoiesis. Diagnosis is made through exclusion of other etiologies, including biliary atresia. Therapy is directed at addressing the malabsorptive consequences of cholestasis, which include malnutrition, growth retardation, fat-soluble vitamin deficiencies, and calcium deficiency.
Toxoplasmosis: Sixty percent have hepatomegaly, and 40% have hyperbilirubinemia. Hepatic pathology is nonspecific and includes mononuclear periportal inflammation and canalicular bile stasis. Diagnosis is made serologically or through identification of the parasite in cerebrospinal fluid (CSF) sediment. Antiparasitic therapy (pyrimethamine and sulfadiazine) may arrest disease progression.
Rubella: Sixty-five percent have hepatomegaly, and 15% have jaundice. Clinical presentation and hepatic pathology are nonspecific. Elevated aspartate aminotransferase (AST) and alanine amino transferase (ALT) levels may occur in addition to acholic stools. Progressive hepatic disease, including fibrosis and failure, is uncommon. No specific therapy is indicated.
Cytomegalovirus (CMV): Hepatosplenomegaly, jaundice, and elevated AST and ALT levels may occur. Liver biopsy shows focal areas of hepatocyte necrosis with portal inflammation composed of lymphocytes and neutrophils. Intranuclear viral inclusions are more commonly noted in bile duct epithelia than in hepatocytes. Giant cell transformation, bile stasis, and extramedullary hematopoiesis may be seen. Diagnosis is made through culture of the organism from urine or tissue. Progression to severe chronic liver disease is rare. Severe disease may be treated with ganciclovir.
Herpes Simplex: Jaundice and massive hepatic necrosis with liver failure may occur. Coxsackievirus and echovirus (types 11, 14, and 19) infection may present similarly. Diagnosis is made through viral isolation and serology. Documented infection is treated with adenine arabinoside or acyclovir.
Syphilis: Eighty percent have hepatomegaly, and 40% are jaundiced. Biopsy may show extramedullary hematopoiesis, parenchymal or portal inflammatory infiltrates, and granulomatous lesions. Although spirochetes may be seen, the diagnosis is typically made by serologic studies. Although penicillin is essential for the therapy of infants infected with syphilis, it may exacerbate syphilitic hepatic disease.