Hepatitis AVirus

GENERAL PRINCIPLES

• Transmitted via fecal-oral route and is the most common cause of acute viral hepatitis worldwide.

• Large-scale outbreaks can occur due to contamination of food and drinking water.

• A vaccine is available, with two doses given at least 6 months apart.

• The period of greatest infectivity is 2 weeks before the onset of clinical illness.

• Viral shedding in infected patients' feces continues for 2-3 weeks after the onset of symptoms.

DIAGNOSIS

• HAV can be silent (subclinical), especially in children and young adults. Symptoms vary from mild illness to ALF and commonly include malaise, fati gue, pruritus, headache, abdominal pain, myalgias, arthralgias, nausea, vomiting, anorexia, and fever.

• Physical examination may reveal jaundice, hepatomegaly, and, in rare cases, lymphadenopathy, splenomegaly, or a vascular rash.

• Aminotransferase elevations range from 10 to 100 times the upper limit of normal (ULN).

• The diagnosis of acute HAV is made by the detection of IgM anti-HAV antibodies.

• The recovery phase and immunity phase are characterized by the presence of IgG anti-HAV antibodies and the decline of IgM anti-HAV antibodies.

• Liver biopsy is rarely needed.

• ALF is rare. The risk increases with age: 0.1% in patients younger than 15 years to gt;1% in patients older than 40 years.

TREATMENT

• Supportive symptomatic treatment.

• Liver transplantation should be considered for ALF.

Outcome and Prognosis

• Symptoms of acute HAV hepatitis may last from weeks to months (median 8 weeks). HAV does not progress to chronic viral hepatitis.

• A prolonged cholestatic disease, characterized by persistent jaundice and waxing and waning of liver enzymes, is more frequently seen in adults.