Hepatitis (plural hepatitides) implies injury to the liver characterized by the presence of inflammatory cells in the tissue of the organ. The name is from ancient Greek hepar (ηπαρ) or hepato- (ηπατο-), meaning liver, and suffix -itis, meaning "inflammation" (c. 1727). The condition can be self-limiting, healing on its own, or can progress to scarring of the liver. Hepatitis is acute when it lasts less than six months and chronic when it persists longer. A group of viruses known as the hepatitis viruses cause most cases of liver damage worldwide. Hepatitis can also be due to toxins (notably alcohol), other infections or from autoimmune process. It may run a subclinical course when the affected person may not feel ill. The patient becomes unwell and symptomatic when the disease impairs liver functions that include, among other things, removal of harmful substances, regulation of blood composition, and production of bile to help digestion.

Causes

Acute hepatitis

• Viral Hepatitis: Hepatitis A through E (more than 95% of viral cause), Herpes simplex, Cytomegalovirus, Epstein-Barr, yellow fever virus, adenoviruses.
• Non viral infection: toxoplasma, Leptospira, Q fever, rocky mountain spotted fever
• Alcohol
• Toxins: Amanita toxin in mushrooms, carbon tetrachloride, asafetida
• Drugs: Paracetamol, amoxycillin, antituberculosis medicines, minocycline and many others (see longer list below).
• Ischemic hepatitis (circulatory insufficiency)
• Pregnancy
• Auto immune conditions, e.g. Systemic Lupus Erythematosus (SLE)
• Metabolic diseases, e.g. Wilson's disease

Chronic hepatitis

• Viral hepatitis: Hepatitis B with or without hepatitis D, hepatitis C (Hepatitis A and E do not lead to chronic disease)
• Autoimmune: Autoimmune hepatitis
• Alcohol
• Drugs: methyldopa, nitrofurantoin, isoniazid, ketoconazole
• Non-alcoholic steatohepatitis
• Heredity: Wilson's disease, alpha 1-antitrypsin deficiency
• Primary biliary cirrhosis and primary sclerosing cholangitis occasionally mimic chronic hepatitis

Signs and symptoms

Acute hepatitis

Clinically, the course of acute hepatitis varies widely from mild symptoms requiring no treatment to fulminant hepatic failure needing liver transplantation. Acute viral hepatitis is more likely to be asymptomatic in younger people. Symptomatic individuals may present after convalescent stage of 7 to 10 days, with the total illness lasting 2 to 6 weeks. V.G. Bain and M. Ma, Acute Viral Hepatitis, Chapter 14, First principle of gastroenterology (an online text book)