Hepatitis C infection is an infection of the liver caused by the hepatitis C virus (HCV). 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. In the U.S., the number of new cases of HCV infection has declined from a peak of 200,000 annually to about 17,000 in 2007. When the virus first enters the body, however, there usually are no symptoms, so these numbers are estimates. Up to 85% of newly-infected people fail to eliminate the virus and become chronically infected. In the U.S., more than three million people are chronically infected with HCV. Infection is most commonly detected among people who are 40 to 60 years of age, reflecting the high rates of infection in the 1970s and 1980s. There are 8,000 to 10,000 deaths each year in the U.S. related to HCV infection. HCV infection is the leading cause of liver transplantation in the U.S and is a risk factor for liver cancer.
Signs and symptoms
Hepatitis C infection causes acute symptoms in 15% of cases. Symptoms are generally mild and vague, including a decreased appetite, fatigue, nausea, muscle or joint pains, and weight loss. Most cases of acute infection are not associated with jaundice. The infection resolves spontaneously in 10-50% of cases, which occurs more frequently in individuals who are young and female.
About 80% of those exposed to the virus develop a chronic infection. Most experience minimal or no symptoms during the initial few decades of the infection, although chronic hepatitis C can be associated with fatigue. Hepatitis C after many years becomes the primary cause of cirrhosis and liver cancer. About 10–30% of people develop cirrhosis over 30 years. Cirrhosis is more common in those co-infected with hepatitis B or HIV, alcoholics, and those of male gender. Those who develop cirrhosis have a 20-fold greater risk of hepatocellular carcinoma, a rate of 1–3% per year, and if this is complicated by excess alcohol the risk becomes 100 fold greater. Hepatitis C is the cause of 27% of cirrhosis cases and 25% of hepatocellular carcinoma worldwide.
Liver cirrhosis may lead to portal hypertension, ascites (accumulation of fluid in the abdomen), easy bruising or bleeding, varices (enlarged veins, especially in the stomach and esophagus), jaundice, and a syndrome of cognitive impairment known as hepatic encephalopathy. It is a common cause for requiring a liver transplant.
Hepatitis C is also rarely associated with Sjögren's syndrome (an autoimmune disorder), thrombocytopenia, lichen planus, diabetes mellitus, and B-cell lymphoproliferative disorders. Thrombocytopenia is estimated to occur in 0.16% to 45.4% of people with chronic hepatitis C. Putative associations with Hyde's prurigo nodularis and membranoproliferative glomerulonephritis have been reported. Hepatitis C infection is also associated with a condition called mixed cryoglobulinemia, which is inflammation of small and medium sized blood vessels (or vasculitis) caused by deposition of immune complexes involving cryoglobulins
HCV induces chronic infection in 50–80% of infected persons. Approximately 40-80% of these clear with treatment. In rare cases, infection can clear without treatment. Those with chronic hepatitis C are advised to avoid alcohol and medications toxic to the liver, and to be vaccinated for hepatitis A and hepatitis B. Ultrasound surveillance for hepatocellular carcinoma is recommended in those with accompanying cirrhosis.
In general, treatment is recommended in those with proven HCV infection liver abnormalities. Current treatment is a combination pegylated interferon alpha and the antiviral drug ribavirin for a period of 24 or 48 weeks, depending on HCV genotype. When combined with ribavirin, pegylated interferon-alpha-2a may be superior to pegylated interferon-alpha-2b, though the evidence is not strong. Improved outcomes are seen in 50–60% of people.Combining either boceprevir or telaprevir with ribavirin and peginterferon alfa improves antiviral response for hepatitis C genotype 1. Adverse effects with treatment are common, with half of people getting flu like symptoms and a third experiencing emotional problems. Treatment during the first six months is more effective than once hepatitis C has become chronic. If someone develops a new infection and it has not cleared after eight to twelve weeks, 24 weeks of pegylated interferon is recommended. In people with thalassemia, ribavirin appears to be useful but increases the need for transfusions.
Several alternative therapies are claimed by their proponents to be helpful for hepatitis C including milk thistle, ginseng, and colloidal silver. However, no alternative therapy has been shown to improve outcomes in hepatitis C, and no evidence exists that alternative therapies have any effect on the virus at all.