Hepatitis

Hepatitis
Caption	An electron micrograph of the Hepatitis B virus
Field	Gastroenterology, Hepatology, Infectious disease
Complications	Cirrhosis, Liver failure, Hepatocellular carcinoma
Causes	Viral infection, Toxic agents, Autoimmune disease
Diagnosis	Blood test, Liver biopsy, Elastography
Prevention	Vaccination, Hygiene, Safe sex
Treatment	Antiviral therapy, Immunosuppression, Liver transplantation

Hepatitis. It is a medical condition characterized by inflammation of the liver, a vital organ responsible for numerous metabolic functions. The condition can be self-limiting or progress to fibrosis, cirrhosis, or liver cancer. Its etiology is diverse, encompassing infectious and non-infectious causes, with viral infections being the most common culprits globally.

Types of hepatitis

The primary classification is based on causative agents. Viral hepatitis includes several distinct forms caused by specific hepatotropic viruses. These are designated hepatitis A, hepatitis B, hepatitis C, hepatitis D, and hepatitis E. Other infectious causes can involve viruses like the Epstein–Barr virus or Cytomegalovirus. Non-viral types are significant and include alcoholic hepatitis, resulting from excessive ethanol consumption, and autoimmune hepatitis, where the body's immune system attacks liver cells. Additional forms are drug-induced hepatitis, often linked to medications like acetaminophen or isoniazid, and metabolic disorders such as Wilson's disease.

Causes and transmission

Transmission routes vary drastically by type. Hepatitis A and Hepatitis E are typically spread via the fecal–oral route, often through contaminated food or water, and are associated with areas of poor sanitation. In contrast, Hepatitis B, Hepatitis C, and Hepatitis D are primarily blood-borne. Transmission occurs through exposure to infected blood or bodily fluids, via unscreened transfusions, sharing of contaminated needles, unprotected sex, or from mother to child during childbirth. Non-infectious causes involve direct liver injury from toxins like alcohol or certain pharmaceuticals, or from aberrant autoimmune activity.

Signs and symptoms

Acute presentation may include fatigue, malaise, loss of appetite, nausea, vomiting, abdominal pain, particularly in the right upper quadrant, dark urine, clay-colored stool, joint pain, and jaundice, which is a yellowing of the skin and sclera. Many cases, especially of hepatitis C, can be asymptomatic. Chronic infection, often seen with hepatitis B and hepatitis C, may progress silently for decades before manifesting as complications like ascites, hepatic encephalopathy, or signs of portal hypertension such as esophageal varices.

Diagnosis

Diagnosis begins with a clinical assessment and medical history. Key blood tests include liver function tests to measure elevated ALT and AST levels. Serological tests detect specific antigens and antibodies; for instance, the HBsAg confirms hepatitis B infection. PCR assays quantify viral load. Imaging studies like ultrasound, CT, or MRI assess liver structure. Definitive evaluation of liver damage often requires a liver biopsy, though non-invasive techniques like FibroScan are increasingly used.

Prevention

Preventive strategies are highly effective for several types. Vaccination is available for hepatitis A and hepatitis B; the hepatitis B vaccine also prevents hepatitis D. Other measures include ensuring safe water supplies, practicing good personal hygiene, and employing food safety protocols. For blood-borne types, prevention focuses on screening blood donations, using sterile needles, implementing harm reduction programs like needle exchanges, and practicing safe sex. Avoiding excessive alcohol consumption and careful medication management can prevent toxic forms.

Treatment and management

Management depends on the type and chronicity. Acute viral hepatitis often requires only supportive care, including rest, hydration, and avoidance of hepatotoxic substances. For chronic hepatitis B, antiviral agents like tenofovir or entecavir are used to suppress the virus. Chronic hepatitis C is now curable in most patients with direct-acting antiviral regimens such as sofosbuvir/ledipasvir. Autoimmune hepatitis is typically managed with steroids like prednisone and immunosuppressants such as azathioprine. End-stage liver disease from any cause may necessitate liver transplantation.

Epidemiology

Hepatitis is a global public health challenge. The World Health Organization estimates that hundreds of millions live with chronic hepatitis B or hepatitis C infection, with high prevalence in regions like the Western Pacific and Africa. Hepatitis A is common in areas with developing sanitation infrastructure, while hepatitis E causes outbreaks in parts of Asia and Africa. Alcoholic hepatitis remains a major cause of liver disease in many developed nations. Significant efforts to combat viral hepatitis are spearheaded by organizations like the Centers for Disease Control and Prevention and the World Health Assembly.

Category:Hepatology Category:Inflammations Category:Viral diseases