Chronic hepatitis - Patterns of liver disease

Chronic hepatitis

Definition

Chronic hepatitis is a clinical and pathological syndrome characterised by a variable degree of hepatocellular necrosis and inflammation, without improvement for at least 6 months. However, it is sometimes diagnosed earlier than this.

Aetiology

The main causes of chronic hepatitis:

·        Viral hepatitis: Hepatitis B virus (+/− hepatitis D), hepatitis C virus.

·        Autoimmune: Autoimmune chronic hepatitis, primary biliary cirrhosis (PBC).

·        Toxic: Alcoholinduced hepatitis (rare), drug-induced hepatitis (methyldopa, isoniazid, ketoconazole, anti-retroviral drugs).

·        Nonalcoholic hepatosteatosis (NASH).

·        Inherited: Wilson’s disease, α1 antitrypsin deficiency, haemochromatosis.

Clinical features

Patients may present with non-specific symptoms (malaise, anorexia and weight loss) or with the complications of cirrhosis such as portal hypertension (bleeding oesophageal varices, ascites, encephalopathy). Following acute viral hepatitis persistently raised serum transaminases (aspartate transaminase, alanine aminotransferase) may be detected during follow-up. Asymptomatic patients with chronic viral hepatitis may be detected during screening at blood donation.

Microscopy

Features include lymphocyte infiltration, fibrosis and fat deposition. Histologically three patterns of chronic hepatitis are seen.

Chronic active hepatitis (CAH). A severe pattern which is likely to progress rapidly to cirrhosis with chronic inflammatory cells infiltrating the portal tracts and extending into the lobule with ‘piecemeal necrosis’. Fibrous tissue formation links portal tracts to central veins or central veins to each other (bridging necrosis).

Chronic persistent hepatitis (CPH) has a more favourable prognosis unless caused by hepatitis C virus. CPH may also develop into CAH in some e-antigen positive hepatitis B infected patients. Inflammation is confined to the portal tracts.

Chronic lobular hepatitis (CLH) is most commonly associated with viral hepatitis. Hepatitis B patients who are e-antigen positive may develop CAH.

Inflammation of the portal tracts with spotty inflammation in the parenchyma of the lobules, but there is no liver cell necrosis.

Complications

Cirrhosis is the most common complication. There is increased risk of hepatocellular carcinoma in patients with chronic viral hepatitis especially in hepatitis B.

Investigations

Chronic hepatitis is diagnosed by a combination of persistently abnormal liver function tests and the findings on liver biopsy. Other investigations are aimed at diagnosing the underlying cause and providing a prediction of prognosis including serum viral markers and autoantibodies (e.g. antimitochondrial antibodies suggest primary biliary cirrhosis).

Management

Symptomatic management includes adequate nutrition and hydration.

Specific treatments depend on the underlying cause, e.g. antiviral treatment.

Liver transplantation may be indicated.