A Synopsis of AFP'S "Hepatitis C: Diagnosis and Treatment"

A Synopsis of 
Hepatitis C: Diagnosis and Treatment
THAD WILKINS, MD; JENNIFER K. MALCOLM, DO; DIMPLE RAINA, MD; and ROBERT R. SCHADE, MD, Medical College of Georgia, Augusta, Georgia
Am Fam Physician. 2010 Jun 1;81(11):1351-1357.
http://www.aafp.org/afp/2010/0601/p1351.pdf

     Today is a fun day because I'm working on a Saturday, so I have to blog from my iPhone. Anyway, the girls up front were asking me all these questions about hepatitis C, so I figured this would be a good time to review the topic.

     Hepatitis C is a single-stranded RNA virus transmitted through exposure to infected blood. This includes dirty needles from IVDA, unsterilized syringes, unprotected sex, accidental needle sticks, etc. Transmission through blood transfusion occurs three times per 10,000 units transfused. Blood was not screened for Hep C until after 1992. Immunoglobulin has not been shown to be effective as a treatment in these situations.There is no vaccine available and the USPSTF does not recommend screening in asymptomatic low risk patients. 

     Symptoms are nonspecific and include fatigue, nausea, anorexia, myalgias, arthralgias, weakness and weight loss. Most patients are asymptomatic. Hepatitis C can lead to cirrhosis, causing portal hypertension, hemorrhage, and hepatocellular carcinoma. Risk factors are being male, immunosuppression, coinfection with HIV or HBV, or age greater than 40. Daily alcohol use can greatly accelerate the severity of damage. Median survival of hepatocellular carcinoma is eight months.

    Diagnostic tests are used to diagnose HCV. The screening test is the enzyme linked elisa test, which detects viral antibodies. The two confirmatory tests are the RIA (for antibodies against the HCV antigens) and PCR (for HCV RNA). If they are both negative after a positive screen, then it was a false positive. If all three tests are positive, then the patient is experiencing a current infection. If the screener and RIA are positive but the PCR is negative, then it signals an old infection.  Quantitative viral load is used to document the progress of the infection and the effectiveness of treatment. Surveillance of hepatocellular carcinoma should be considered as well.

    the goal of treatment is to slow down the progression of fibrosis and cirrhosis. Fibrosis can be predicted with a scoring system using platelet count and AST. Biopsy is another way to assess fibrosis. The standard therapy is pegylated interferon (alfa-2a and alfa-2b) and ribavirin.  Interferon can cause leukopenia, thrombocytopenia, and thyroiditis. Ribavirin can affect the kidneys (its renally excreted). HCV phenotypes 1 and 4 are treated for 48 weeks. Genotypes 2 and 3 are treated for 24 weeks. Therapy effectiveness is measured by sustained viral response. If the virus is undetectable after 4 weeks, this shows a rapid and sustained viral response and the treatment may be discontinued earlier than expected. If it is undetectable after 12 weeks, treatment should be continued until week 48.  A 100-fold reduction in viral load after 12 weeks is predictive of a partial response. The load should be recheck after another 12 weeks to determine if the therapy should be continued for another 48-72 weeks. If the treatment fails to decrease the load by 100-fold after week 12, or if the load is stable, the therapy can be discontinued.