Chronic non-viral hepatitis

Chapter 38 CHRONIC NON-VIRAL HEPATITIS






CAUSES


The causes of non-viral chronic hepatitis are listed in Table 38.1. The principal cause is autoimmune hepatitis. Less common causes include drug-induced hepatitis and cryptogenic hepatitis. The hereditary metabolic liver diseases, Wilson’s disease and alpha1-antitrypsin deficiency, may also cause a chronic hepatitis-like picture. Diseases mimicking chronic hepatitis include non-alcoholic steatohepatitis, sclerosing cholangitis and primary biliary cirrhosis.


TABLE 38.1 Non-viral causes of chronic hepatitis





















Cause Specific histology
Autoimmune hepatitis Interface and lobular hepatitis, plasma cell and lymphocytic infiltrate, rosette formation, bridging and confluent necrosis
Drugs and toxins Similar to chronic viral hepatitis; may be autoimmune hepatitis-like; ± eosinophils; ± granulomas
Cryptogenic Similar to autoimmune hepatitis
Wilson’s disease Copper deposits
Alpha1-antitrypsin deficiency Eosinophilic globules in periportal zones


Autoimmune hepatitis


Autoimmune hepatitis (AIH) accounts for about 20% of cases of chronic hepatitis. The disease has a female preponderance, affects all ages and has a worldwide distribution. There is a genetic association with the human leucocyte antigens B8, DR3 and DR4. The cause of AIH is unknown. Autoantibodies including antinuclear antibody (ANA) and anti-smooth muscle antibody (SMA) are very common but not specific for the disease or of pathogenetic significance. At least two types of AIH are recognised.


Type 1 AIH is the most common form representing 80% of cases. It is characterised by the presence of ANA and/or SMA and hypergammaglobulinaemia. The peak incidence occurs between the ages of 16 and 30 years, with 70% being females younger than 40 years. Around 30%–50% of patients have concurrent immune diseases including ulcerative colitis, autoimmune thyroiditis and synovitis. The clinical course is often indolent. Symptoms may start abruptly in 40% of patients, but an acute fulminant presentation occurs rarely. Cirrhosis may be present at diagnosis in 25% of cases.


Type 2 AIH is a rare disorder that predominantly affects children aged between 2 and 14 years. It is characterised by the presence of antibodies to liver-kidney microsome type 1 (anti-LKM-1). The target autoantigen is the drug metabolising enzyme, cytochrome mono-oxygenase P450 IID6 (CYP2D6). Extrahepatic immune diseases occur more commonly than in type 1 AIH. There is an association with autoimmune polyglandular syndrome type 1. The clinical course is more aggressive than type 1 AIH with a higher frequency of progression to cirrhosis.






CLINICAL FEATURES




Mar 29, 2017 | Posted by in GASTROENTEROLOGY | Comments Off on Chronic non-viral hepatitis
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