Clinical Syndromes - Hepatitis B Virus

Clinical Syndromes

Hepatitis B virus is one of the most important causes of acute and chronic hepatitis. The clinical manifestations vary from subclinical hepatitis to symptomatic and icteric hepatitis. The incubation period varies from 6 weeks to 6 months. The clinical manifestations of HBV infection depend on (a) age of infection, (b) immune status of the host, and (c) the level of HBV.

◗ Acute hepatitis B virus infection

The prodromal or preicteric phase is characterized by gradual onset of anorexia, malaise, and fatigue. During the icteric phase, the liver becomes tender with development of jaundice. Nausea, vomiting, and pruritus with passing of dark-colored urine are the symptoms noted in this stage. Clinical manifesta-tions of acute hepatitis B are similar to that of hepatitis A but with the difference that the symptoms tend to be more severe and life-threatening with HBV infection. The clinical disease associated with acute HBV infection may range from mild disease to a disease as severe as fulminant hepatitis occurring in less than 1% of the patients.

◗ Chronic hepatitis B virus infection

Chronic HBV infection is one of the major complications of HBV infection. The risk of chronic infection is also higher in those infected at birth (90%) and in patients who are immuno-compromised. Only 5–10% of older children or adults progress to develop chronic infection.

Complications of Hepatitis B virus infection: Cirrhosis andhepatocellular carcinoma are the long-term but rare complica-tions of hepatitis B. Perinatal transmission or infection in children is associated with few or no symptoms, but infection has a high risk of becoming chronic. Fulminant hepatic failure is another major complication of HBV infection. This condition occurs in approximately 0.5–1% of HBV-infected patients. The condition progresses to fulminant hepatic failure with coagulopathy, encephalopathy, and cerebral edema. The case fatality rate of these patients is very high nearing 80%.

Patients with chronic HBV infection have a very high risk of developing hepatocellular carcinoma. The cancer appears to be due to repeated episodes of chronic inflammation and cellu-lar regeneration. The cancer that develops an average of 25–30 years after initial infection is the leading cause of cancer-related deaths in areas where HBV is endemic.

Glomerulonephritis, polyarteritis nodosa, varieties of skin manifestations, cardiopulmonary manifestations, and joint and neurologic manifestations are other important complica-tions of HBV infection.