Hepatitis C is an infectious liver disease caused by a blood-borne virus called the hepatitis C virus, or HCV. An acute phase is followed by chronic hepatitis in up to 80 percent of patients. Chronic hepatitis C is the commonest form of chronic liver disease in the US, causing 8 000 to 13 000 deaths annually, and being the main indication for liver transplantation.
Direct (blood-borne) transmission of the HCV causes the condition. Most cases can be traced to intravenous drug use, or blood transfusion, although transfusion-related cases are fewer nowadays, due to better screening of blood products and donors. Some cases have been traced to body piercing, tattoos and sharing cocaine straws. An HCV infected mother has a 5 percent chance of infecting her baby during birth. Cases have been recorded of HCV transmission from infected donors whose organs (liver, heart, kidney) were used for transplantation.
Symptoms and diagnosis
Acute hepatitis C
Hepatitis C accounts for 20 percent of acute hepatitis cases. Most sufferers have no, or very mild, symptoms, and are very seldom jaundiced. The acute phase may last up to 3 months, with general malaise, decreased appetite, nausea, and mild abdominal pain. Because of the mild and non-specific symptoms, many cases are only diagnosed after several months. Progression to fulminant hepatitis is rare. About 80 percent of cases go on to develop chronic hepatitis C, and of these, about a third will later develop cirrhosis and liver cancer.
Suspected cases are investigated by:
- full blood count - for red cell, white cell and platelet function,
- liver tests - to measure function and detect liver damage, and
- tests for HCV antibodies - 80 percent will have antibodies within 15 weeks of exposure/infection.
About 30 percent of patients can clear the virus from their system during the acute phase. If the body cannot clear the virus within six months, a state of chronic hepatitis C develops, and it is these patients who have the increased risk of cirrhosis and liver cancer. By this stage, the chance of spontaneous viral clearance is very low.
Chronic hepatitis C
Symptoms are generally mild, and non-specific, for instance fatigue and weakness, but they lead to a decreased quality of life. A high percentage of these patients develop cirrhosis, which is a major risk factor for liver cancer. It is difficult to predict which patients will progress to these complications, though some proposed indicators include:
- the size of the viral load - so far, thought not to be a predictor;
- age - older patients are more at risk;
- smoking increases the rate of liver fibrosis;
- gender - males are more at risk;
- HIV infection dramatically increases the risk of progression;
- alcohol use increases the risk of progression;
- co-existing fatty liver worsens the outcome; and
- serum alpha-fetoprotein levels do not correlate with outcome and are not an accurate predictor or detector of liver cancer. Raised levels should be further investigated by abdominal scans/ultrasounds or other imaging techniques.
The degree of inflammation and fibrosis found on liver biopsy in selected patients can reliably predict disease progression.
Other illnesses have been linked to chronic hepatitis c, such as autoimmune thryoiditis, cryoglobulinaemia, glomerulonephritis, diabetes and lichen planus.
There is no definitive treatment for hepatitis C, although in cases of high awareness and known risk, immediate post-exposure use of hyper-immune globulin may prevent the development of chronic hepatitis C.
For proven hepatitis C, interferon can be used, or antivirals such as ribavarin. The response is not predictable, though large viral reduction or even clearance has been reported. Early treatment improves the outcome.
(Dr A G Hall)