TREATING HEPATITIS C
It is a clinical challenge treating patients with Hepatitis C (HCV), which very often is found in asymtomatic patients donating blood or patients incidentally found to have elevated liver enzymes on routine blood tests. Some patients may complain of fatique or malaise.
Less than 15% of patients with chronic HCV clear the virus after an acute infection and only about 1% do so after a chronic infection has developed. Using the rule of 20s, about 20% of chronic HCV patients will develop cirrhosis in about 20 years. The risk of liver cancer in HCV related cirrhosis is about 20%. In patients receiving Interferon monotherapy there is a 20% chance of achieving a sustained response.
HCV is an RNA Virus that mutates frequently, which may explain why the antibody tire appears late (4-6 weeks after the onset of symptoms) and why there may not be complete immunity to reinfection and this has made it difficult to develop a vaccine. There are 6 major genotypes of the HCV. Genotypes 1a and 1b are the most common in the U.S., and though these do not produce as severe a liver disease as 2a they are more resistant to alpha interferon therapy.
Third generation EIAs are currently available and are highly sensitive in making a diagnosis. A suspected false positive test should be confirmed by an RIBA test, which is both sensitive and specific. There are 2 assays to measure viral load: the PCR and the branched DNA test. These detect the virus in a suspected case of exposure before the patient develops antibodies or symptoms.
HCV is found mainly in the liver and blood. Body fluids such as saliva, urine, semen and vaginal secretions have rarely been shown to contain the virus and have not been shown to transmit the virus. Sexual transmission is therefore rare and unlike Hepatitis B, and if monogamous and heterosexual, no special precautions are required. Most infection spread has been through practices which include snorting cocaine, tattooing and from blood transfusions. (prior to 1990) and dialysis machines. Maternal fetal transmission occurs in about 5% of cases and in about 30%, the source is undetected.
Therapy is recommended for all patients with chronic HCV with raised ALT levels, HCV RNA positivity and a liver biopsy showing some degree of fibrosis and/or moderate to severe inflammation. Therapy is not recommended for patients with advanced cirrhosis or mild hepatitis with normal liver enzymes although the later is debatable.
Contraindications to therapy include severe neuropsychiatric illness, bone marrow compromise or organ transplant recipients (other than liver). The currently recommended regimen is a combination of Interferon and Ribavirin for 24-48 weeks depending on the genotype and clinical response. Newer therapies are being developed but until then HCV is the most common reason for liver transplant (40%) and almost a billion dollars is spent a year on the treatment of HCV. Early detection and more aggressive therapy will hopefully bring this number down.