Hepatitis C: The Silent Epidemic
Hepatitis C virus is transmitted through bodily fluids and affects the liver. Fifty percent of peopl
Hepatitis C is the most common chronic blood-borne infection and the leading indication for liver transplant in the United States. If left untreated, HCV can cause cirrhosis, end-stage liver disease, and hepatocellular carcinoma. Hepatitis C costs the health-care industry $5.46 billion annually (costs associated with asthma are $5.8 billion).1 Approximately 8000-10,000 HCV patients die each year.
Q. Who gets HCV?
A. Patients are typically men between the ages of 20 and 49. African Americans have a substantially higher prevalence of HCV infection than do whites.
In the coming years, practitioners will be faced with an expanding population of HCV patients due to the development of a serologic test to detect the virus, recent treatment advances, and the publicity surrounding such celebrities as David Crosby, Naomi Judd, and Pamela Anderson, all of whom have revealed that they are infected.
Q. How is HCV transmitted?
A. Hepatitis C is mainly transmitted parenterally. The most common risk factor is IV drug use, which accounts for 60 percent of transmissions in the United States. The risk for infection due to a blood transfusion is 0.001% per unit transfused.
Hepatitis C is more prevalent in IV drug users than other viral infections, including hepatitis B (HBV) and HIV. Research also indicates that HCV infection among IV drug users who do not share syringes may be attributed to sharing cottons or cookers.2 The CDC estimates that after five years of IV drug use, 90% of users will be infected with HCV. Intranasal cocaine use, especially with shared equipment, can also transmit the virus.
Tattooing and body piercing are potential routes of transmission when performed with contaminated equipment.3 According to the CDC, individuals with exposure only to tattooing are not at an increased risk for HCV infection. However, any percutaneous exposure has the potential for transferring infectious blood and transmitting blood-borne pathogens.
Transmission through hemodialysis has decreased dramatically in recent years. Some studies have indicated a correlation between increasing years on dialysis and HCV infection, independent of blood transfusions. Acquisition of HCV in such cases may be due to neglect of infection-control precautions.
The estimated risk of transmission from mother to fetus is 5%-10%. This risk is increased if the mother is seropositive for HIV. Sexual transmission between monogamous partners is uncommon, with a less than five percent rate of infection. Of those infected, many have additional risk factors as well. The CDC reports that approximately 10 percent of HCV-infected patients have no identified source for their infection.
Q. Who should be tested for HCV?
A. The CDC does not recommend routine screening for the general public. Clinicians should assess high-risk practices associated with the transmission of HCV and other blood-borne pathogens. Children born to HCV-positive mothers should be tested at 12-18 months, since passively acquired immunity can persist after birth. Routine testing is not recommended for pregnant women unless the history suggests an increased risk of infection.
Q. What are the clinical features of HCV?
A. Acute infection is asymptomatic in 60-70 percent of HCV-infected patients. Nonspecific symptoms, such as anorexia, malaise, nausea, and abdominal pain, may occur in 10-20 percent of patients, and 20%-30% will have jaundice. Patients may remain asymptomatic for decades and learn of their disease when attempting to donate blood or during routine liver enzyme testing. Less than 40 percent will recover from the acute infection spontaneously and without sequelae, as evidenced by normal aminotransferase levels and the absence of HCV RNA in their serum. Factors associated with spontaneous clearance include younger age, female gender, and certain major histocompatibility complex genes.4 Prospective studies have shown that 60-85 percent of HCV-infected patients will develop chronic disease with detectable virus and fluctuating liver enzymes.4
Physical examination may be normal or may demonstrate mild hepatomegaly or tenderness. In advanced liver disease or cirrhosis, the symptomatology and physical findings are more prominent. Patients may complain of pruritus, abdominal swelling, and dark urine. Physical findings can include hepatomegaly, splenomegaly, jaundice, ascites, palmar erythema, and spider angiomas. Laboratory findings may be significant for leukopenia, thrombocytopenia, prolonged prothrombin time (PT), and elevated aminotransferases. Extrahepatic manifestations are also possible. These are immunologic in origin and include cryoglobulinemia, membranoproliferative glomerulonephritis, and porphyria cutanea tarda.
Q. Is cirrhosis a common effect of chronic HCV?
A. Cirrhosis develops in 10%-20% of patients with chronic HCV. It usually develops over a period of 20-30 years. Older patients tend to have a more rapid progression to cirrhosis. Contributing cofactors include age, alcohol consumption, and coinfection with HIV and/or HBV.
Patients with HCV-associated cirrhosis are also at a higher risk for developing hepatocellular carcinoma. Routine screening with ultrasound and a-fetoprotein is recommended in patients with suspected cirrhosis.5 Hepatocellular carcinoma is rare in patients with chronic HCV who do not have cirrhosis.