Liver is the largest organ in the body and is located in the right upper quadrant of the abdomen &accounts for 1.5 to 2.5 % of lean body mass. Diseases of liver present clinically in a few distinct patterns and are usually classified as hepatocellular diseases, cholestaticdiseases or mixed.
Hepatitis is inflammation of the liver parenchyma. The condition may be clinically in-apparentand self limiting, or may be chronic progressing to fibrosis or scarring of liver, eventually resulting in cirrhosis and liver cancers.
Causes of Hepatitis :
- Viral infections
- Toxins& drug induced
- Autoimmune disorders.
Viral hepatitis :
Viral hepatitis is asystemic infection affecting the liver predominantly. There are five different types of Hepatitis viruses, identified by different letters A,B,C,D and E. While all cause liver disease they vary in important ways. In particular, Hepatitis B and hepatitis C lead to chronic disease in hundreds & millions of people and are among the most common causes of liver cirrhosis and cancer.
Most people do not experience any symptoms during the acute infection phase. However, some people have acute illness with symptoms that last several weeks, including yellowing of the skin and eyes (jaundice), dark urine, extreme fatigue, nausea, vomiting and abdominal pain. Jaundice is the hallmark of liver disease and perhaps the most reliable marker of severity.A small subset of persons with acute hepatitis can develop acute liver failure, which can lead to death.
In some people, hepatitis can also cause a chronic liver infection that can later develop into cirrhosis (a scarring of the liver) or liver cancer.
Hepatitis A and E are typically caused by ingestion of contaminated food or water. Hepatitis B, C and D usually occur as a result of parenteral contact with infected body fluids. Common modes of transmission for these viruses include receipt of contaminated blood or blood products, invasive medical procedures using contaminated equipment and for hepatitis B transmission from mother to baby at birth, from family member to child, and also by sexual contact.
Hepatitis B is a potentially life-threatening liver infection caused by the hepatitis B virus (HBV) that can cause chronic infection and puts people at high risk of death from cirrhosis and liver cancer.
A vaccine against hepatitis B has been available. The vaccine is 95% effective in preventing infection and the development of chronic disease and liver cancer due to hepatitis B.
Toxic & drug induced hepatitis:
- Among patients with acute liver failure, drug induced hepatitis is the common cause.Hepatotoxicity may be direct or idiosyncratic. Most commonly used drugs that cause hepatitis includes anticonvulsants like Phenytoin, Phenobarbitone, antifungal agents like ketaconazole, Anti TB drugs like Isoniazid, rifampicin.
- Direct hepatotoxicity is dose dependent, predictable and has a short interval between exposure and liver injury.Idiosyncratic reactions are unpredictable, may occur at anytime during or shortly after exposure to the drug
- Treatment of drug induced hepatitis is largely supportive. Withdrawal of the suspected agent is indicated at the first sign of an adverse reaction.
Autoimmune hepatitis is a chronic disorder characterized by hepatocellular necrosis, usually with fibrosis progressing to cirrhosis and liver failure.Evidence suggests that the progressive liver injury in patients with autoimmune hepatitis is a result of cell mediated immunological attack directed against liver cells. Most often predisposition to autoimmunity is inherited. Mainstay of management of autoimmune hepatitis is glucocorticoid therapy.
Important diagnostic tests in liver diseases:
Typical battery of tests used for initial assessment of liver diseases includes measurements of
- Serum aminotransferases
- Alkaline phosphatase
- Bilirubin levels
- Prothrombin time
- Hepatitis serology : HbsAg, Anti HBc IgM, HBeAg, Anti HCV, Anti HAV IgM
- Antinuclear antibody (ANA),Antimitochondrialantibody (AMA), P-ANCA
- Drug history
- Imaging studies : Ultrasound, CT and MRI scans.
- Liver biopsy remains the standard criterion, particularly in evaluation of patients with chronic liver disease
Management of liver diseases includes advice of alcohol use, medications, vaccinations and surveillance for complications. Abstinence from alcohol should be encouraged for all patients with alcohol related liver disease.
All patients with risk factors for liver disease should be vaccinated against Hepatitis A and Hepatitis B. Cirrhosis of liver warrants screening & long term surveillance for hepatocellular carcinoma.