Viruses

In neonates: Hepatomegaly, jaundice, congenital defects

In adults: Mononucleosis-like illness with hepatitis; may occur posttransfusion

Infectious mononucleosis

Clinical hepatitis with jaundice in 5-10%; subclinical liver involvement in 90-95%

Acute hepatitis sometimes severe in young adults

Jaundice, systemic toxicity, bleeding

Liver necrosis with little inflammatory reaction

Hepatic infection occasionally due to echovirus or coxsackievirus infections, varicella, herpes simplex, rubella, or rubeola

Bacteria

Granulomatous reaction of liver with progressive necrotizing abscesses

Serious infection acquired via portal pyemia, cholangitis, or hematogenous or direct spread; due to various organisms, especially gram-negative and anaerobic

Illness and toxicity, yet only mild liver dysfunction

Hepatic involvement (common; usually subclinical) with granulomatous infiltration; jaundice (rare)

Disproportionately increased alkaline phosphatase

Minor focal hepatitis in numerous systemic infections (common; usually subclinical)

Fungi

Granulomas in liver and spleen (usually subclinical) that heal with calcification

Granulomatous infiltration sometimes occurring in cryptococcosis, coccidioidomycosis, blastomycosis, or other infections

Protozoa

Important disease, often without obvious dysentery

Usually a large single abscess with liquefaction

Systemic illness, tender hepatomegaly, surprisingly mild liver dysfunction

A common cause of hepatosplenomegaly in endemic areas

Jaundice absent or mild unless active hemolysis is present

Transplacental infection

In neonates: Jaundice, CNS and other systemic manifestations

Infiltration of reticuloendothelial system by parasite, hepatosplenomegaly

Helminths

Biliary obstruction by adult worms, parenchymal granulomas caused by larvae

Biliary tract infestation, cholangitis, stones, cholangiocarcinoma

One or more hydatid cysts, which usually have a calcified rim and may be large but which often are asymptomatic and do not disrupt liver function

Can rupture into the peritoneum or biliary tract

Acute: Tender hepatomegaly, fever, eosinophilia

Chronic: Biliary fibrosis, cholangitis

Periportal granulomatous reaction to ova with progressive hepatosplenomegaly, pipestem fibrosis, portal hypertension, and varices

Hepatocellular function preserved; not true cirrhosis

Visceral larva migrans syndrome

Hepatomegaly with granulomas, eosinophilia

Spirochetes

Acute fever, prostration, jaundice, bleeding, renal injury

Liver necrosis (often mild despite severe jaundice)

Congenital: Neonatal hepatosplenomegaly, fibrosis

Acquired: Variable hepatitis in secondary stage, gummas with irregular scarring in tertiary stage

Borrelia infection

Systemic symptoms, hepatomegaly, sometimes jaundice

Unknown

Active chronic granulomatous inflammation not resulting from known causes (sarcoid variant?)

May cause mainly systemic symptoms (eg, fever, malaise) and can occur when certain drugs are used

Granulomatous infiltration (common, usually subclinical), jaundice (rare)

Occasionally, progressive inflammation with scarring and portal hypertension