Symptoms of uncomplicated chronic hepatitis B
Some patients with acute hepatitis B do not clear the virus (less than 5%) and will progress to chronic hepatitis. Chronic hepatitis B is defined as persistence of HBsAg in the circulation for more than six months.
The disease can cause mild to serious liver damage as well as active hepatitis, cirrhosis and primary liver cancer.
The persistence of abnormal alanine aminotransferase levels for more than six months after the onset of acute hepatitis B indicates disease progression and is usually accompanied by serological evidence of continued infection.
Chronic hepatitis B is more likely to follow infections acquired in childhood than those acquired in adult life. 90% of neonates infected at birth will develop chronic hepatitis B unless vaccination is given.
Only a small percentage of patients with chronic infection give a history of acute hepatitis or jaundice. Physical examination in chronic hepatitis B may show no physical abnormalities and many patients show no symptoms of liver disease. If symptoms are present, they are usually non-specific and mild.
With more advanced disease there may be spider naevi and hepatomegaly (enlarged liver). Muscle wasting, ascites, oedema, palmar erythema, encephalopathy and bruising, suggest advanced disease with cirrhosis.
The symptoms of portal hypertension, such as ascites and bleeding oesophageal varices, are late features of hepatitis B and cirrhosis.
There are several signs to look out for:
• Fatigue is the most common symptom, variously described as a lack of energy, lassitude or the feeling that one is ageing.
• With the development of cirrhosis, weight loss, weakness, muscle wasting, abdominal swelling, encephalopathy, oedema, dark urine and jaundice may become progressive problems. Many carriers may be detected through routine screening for HBsAg e.g. in pregnancy.
• Older patients may present with complications of active hepatitis and cirrhosis or with HCC.
• A small proportion of patients may present with extrahepatic manifestations of HBV infection – glomerulonephritis, vasculitis, or polyarteritis, for example.
Interpreting laboratory results
The following liver function tests (LFTs) are used to determine the presence of liver disease.
• ALT – tests usually show an increase in ALT although young carriers with high levels of hepatitis B may have normal ALT levels. Recording single measures of ALT is less useful in a disease as dynamic as hepatitis B as aminotransferases may fluctuate over time.
• AST – tests will usually show an increase in AST.
• Serum bilirubin and albumin tests – usually normal unless the disease is severe and advanced.
• Prothrombin time – usually normal length unless the disease is severe and advanced.
The utility of HBV genotypes is still being determined but there is a suggestion that response to interferon is higher in genotypes A and B versus genotypes C and D. In comparison with genotype C, genotype B is associated with spontaneous HBeAg seroconversion at a younger age, less active liver disease, slower progression to cirrhosis and less frequent development of HCC. Genotype D is associated with HBeAg-negative chronic hepatitis B.
The terms used to describe the pathology of chronic hepatitis are being reappraised. More emphasis is now placed on grading the degree of inflammation and staging the extent of fibrosis.
Reporting cases
Hepatitis B, like all viral forms of hepatitis, is a notifiable disease and doctors have a statutory duty to notify their ‘proper officer’ of the local authority, who is usually the consultant in communicable disease in the local health protection unit, of suspected and confirmed cases. They will pass on the information to the national centres. This information is used to help plan local services for prevention and treatment.