What is hepatitis C infection?
'Hepatitis' means inflammation of the liver. HCV is one of several viruses that can infect the liver and cause hepatitis. It is difficult for the human immune system to eliminate HCV from the body, and infection with HCV usually becomes chronic. Over decades, chronic infection with HCV damages the liver and can cause liver failure. Up to 85% of infected people fail to eliminate the virus and become chronically infected. Infection is most common between 40 to 60 years of age, reflecting the high rates of infection in the 1970s and 1980s. HCV infection is the leading cause of terminal liver disease necessitating liver transplantation, and is a risk factor for liver cancer.
There are six distinct known strains of the virus with different genetic profiles (genotypes). Genotyping is important to guide treatment because some viral genotypes respond better to therapy than others. The genetic diversity of HCV is one reason that it has been difficult to develop an effective vaccine since the vaccine must protect against all genotypes.
What are the symptoms of hepatitis C infection?
About 75% of people have no symptoms when they first acquire HCV infection. The remaining 25% may complain of fatigue, loss of appetite, muscle aches or fever. Yellowing of the skin or eyes (jaundice) is rare at this early stage.
Over time, people with chronic infection may begin to experience the effects of the persistent inflammation of the liver caused by the immune reaction to the virus. Blood tests may show elevated levels of liver enzymes, a sign of liver damage, which is often the first suggestion that the infection may be present. Patients may become easily fatigued or complain of nonspecific symptoms.
As cirrhosis develops, symptoms increase and may include:
In patients with advanced cirrhosis, the liver begins to fail, which is life-threatening. Confusion and even coma (encephalopathy) may result from the inability of the liver to process toxic substances.
Increased pressure in the blood vessels of the liver (portal hypertension) may cause fluid to build up in the abdominal cavity (ascites) and result in engorged veins in the swallowing tube (esophageal varices) that tear easily and can bleed suddenly and massively. In addition, spleen can get enlarged resulting in low red blood cells (anemia), or low platelets (thrombocytopenia), which can cause bleeding. Advanced liver disease can also cause kidney failure.
Patients with advanced cirrhosis often develop jaundice and deficiency of clotting factors and other proteins which are normally manufactured by the liver.
How does liver damage occur in hepatitis C infection?
The presence of HCV in the liver triggers the human immune system, which leads to inflammation. Over time (usually decades), prolonged inflammation may cause scarring. Extensive scarring in the liver is called cirrhosis. When the liver becomes cirrhotic, it fails to perform its normal functions, (liver failure), and this leads to serious complications and even death. Cirrhotic livers also are more prone to become cancerous.
How is hepatitis C virus spread, is it contagious, and how can transmission be prevented?
HCV is spread through exposure to infected blood, just like Hepatitis B and HIV viruses, in the following situations: