Hepatitis B

Key Features

Essentials of Diagnosis

• Gastrointestinal upset, anorexia, vomiting, diarrhea

• Jaundice, tender hepatomegaly, abnormal liver function tests

• Serologic evidence of hepatitis B disease: HBsAg, HBeAg, anti-HBc IgM

• History of parenteral, sexual, or household exposure or maternal HBsAg carriage

General Considerations

• Incubation period is 45–160 days

• Acquired either perinatally from a carrier mother or later in life from exposure to contaminated blood through shared needles, needle sticks, skin piercing, tattoos, or sexual transmission

• Transmission via blood products is rare

Clinical Findings

Symptoms and Signs

• Most infants and young children are asymptomatic, especially if the infection is acquired vertically

• Slight fever

• Malaise

• Mild gastrointestinal upset

• Visible jaundice is usually the first significant finding and is accompanied by darkening of the urine and pale or clay-colored stools

• Hepatomegaly is frequently present

• Rare presentations

  • Immune complex–mediated rash

  • Arthritis or glomerulonephritis

  • Nephrotic syndrome

Differential Diagnosis

• Viral hepatitis (hepatitis A virus, hepatitis C virus)

• Autoimmune hepatitis

• Wilson disease

• Hemochromatosis

• Nonalcoholic fatty liver disease (NAFLD)

• α₁-Antitrypsin deficiency

• Drug-induced hepatitis

Diagnosis

Laboratory Findings

• Presence of HBsAg and anti-HBc IgM confirms diagnosis

• Recovery from acute infection is accompanied by HBsAg clearance and appearance of anti-HBs and anti-HBc IgG

• Individuals who are immune by vaccination are positive for anti-HBs but negative for anti-HBc IgG

• Presence of HBsAg for at least 6 months indicates chronic infection

• Vertical transmission to newborns is documented by positive HBsAg

• LFT results are similar to those for hepatitis A

• Renal involvement may be suspected on the basis of urinary findings suggesting glomerulonephritis or nephrotic syndrome

Diagnostic Procedure

• Liver biopsy is most useful in chronic infection to determine the degree of fibrosis and inflammation

Treatment

Medical

• Supportive measures are used during the active symptomatic stage of acute infection

• Corticosteroids are contraindicated

• No other treatment is needed for acute HBV infection

• Nucleos(t)ide therapy may be helpful when acute infection is complicated by acute liver failure

• For patients with chronic hepatitis B in whom the immunoactive phase persists for more than 6 months or those who are HBeAg-negative,

  • α-Interferon (5–6 million units/m² of body surface area injected subcutaneously three times a week for 4–6 months)

    • Inhibits viral replication in 30–40% of patients

    • Normalizes the ALT level

    • Leads to the disappearance of HBeAg and the appearance of anti-HBe

    • Side effects are common

    • Younger children may respond better than older children

  • Orally administered nucleoside analog therapy

    • Lamivudine (3 mg/kg/d up to 100 mg/d) and entecavir (0.15–0.5 mg daily depending on age and weight) for children > 2 years old

    • Adefovir (10 mg/d) or tenofovir (300 mg/d) for children > 12 years old

    • Entecavir (0.5 ...