Hepatitis C is a viral infection that affects millions of people around the world. The infection is damaging to the liver in its chronic state, and it is caused by hepatitis C virus (HCV) – a single-stranded RNA virus that is commonly transmitted via injection drug use, blood transfusion, hemodialysis, needle stick injuries and (less commonly) via sexual exposure to infected persons.
There are two main phases of the infection. One is a relatively asymptomatic acute phase that in some cases might be complicated with jaundice and liver damage. The other phase is a chronic phase of HCV infection. Acute infection may resolve on its own; however, nearly 60 to 80 percent of individuals with acute infection may go on to develop a chronic HCV state.
There are six major genotypes or strains of HCV, from 1 to 6. Genotypes 1, 2 and 3 occur worldwide, and of these, 40–80% of all cases are caused by genotype 1. Genotype 4 is commonly detected in the Middle East and Egypt, genotype 5 in South Africa, while genotype 6 is more prevalent in South East Asia.
Acute hepatitis is usually mild and rarely gets complicated leading to liver damage. Approximately 60–80% people with acute infection develop chronic infection. Unlike in acute HCV infection, in these chronic cases viral clearance rates are very low.
Chronic HCV infection may lead to several liver complications, including liver cirrhosis and even liver cancer. For example, studies have shown that 20-30 percent of individuals with chronic HCV infection would go on to develop cirrhosis over a time period of 10–30 years. Chronic HCV infection progresses to these hepatic complications in some patients with certain risk factors. Some of these include:
In patients with cirrhosis there may be a development of further complications such as ascites (i.e. accumulation of water in the abdominal cavity), peritonitis or severe abdominal infection, portal hypertension, neurological complications such as hepatic encephalopathy, hepatic coma, failure of the liver and kidneys, and death.
But cirrhosis is just one of the hepatic complications of chronic HCV. There may be other complications associated with chronic HCV infection that are not strictly related to the liver. These include:
Significant number of cases of chronic HCV infection go on to develop liver cancer, while approximately 1 to 4 percent of patients per year with cirrhosis go on to develop liver cancer. Deaths associated with chronic HCV are commonly due to complications that arise from cirrhosis and liver cancer.
Diagnostic criteria for HCV infection include a positive test for the antibodies to the causative virus (also known as anti-HCV antibodies). To detect the infection, nucleic acid amplification test (NAAT) for HCV RNA and hepatitis C viral antigen(s) should test positive.
Treatment of chronic HCV is recommended for those who have one or more of the following findings:
At present chronic HCV infection is treated with a combination of peginterferon and a drug called ribavirin. Other approved medications for chronic HCV include inteferon-alfa-2b, boceprevir, peginterferon-alfa-2a and peginterferon-alfa-2b.