 Sept. 30 - Oct. 2, 2003 |
| ASSEMBLY EDITION • NEW ORLEANS |
Hepatitis C is a leading cause of cirrhosis in the United States, resulting in 10,000 to 20,000 deaths per year. It is associated with an increased risk of liver cancer, and it represents the most common reason for liver transplantation. About 4 percent of Americans have chronic hepatitis, and among 20- to 45-year-olds, its incidence is as high as 15 percent.
However, only about 20 percent of those who are infected with the hepatitis C virus develop symptoms of the disease, making this infection extremely challenging for family physicians to diagnose and manage.
In a two-hour seminar titled "Hepatitis C in Primary Care" yesterday, William Cassidy, M.D., gave attendees insights into how to diagnose, treat and counsel patients with HCV, emphasizing the natural history of the disease and current treatment options. He is associate professor of medicine at Louisiana State University Health Science Center in Baton Rouge.
Frequent mutations
Hepatitis C is an RNA flavivirus that mutates every time the immune system attacks it and, as a result, tends to become a chronic infection. "Because of its hypervariability, vaccines so far have been impossible to develop, and immunoglobulin is ineffective," Cassidy said.
There are six major genotypes of hepatitis C, but "80 percent of Americans with the disease are of genotype 1, subtype a or b," he said. "The genotype dictates the length of therapy and predicts the patient's therapeutic response. Patients with genotype 1 require longer therapy and have a slower response to therapy."
The infection is transmitted through blood-to-blood contact, and fully 60 percent of individuals who contract hepatitis C in the United States are injection drug users. HCV has also been transmitted through blood transfusions given before 1992. It is rarely transmitted sexually, Cassidy said, but having a large number of sexual partners is associated with higher rates of infection. Studies have shown that monogamous couples are at low risk of getting the disease, he said.
Symptoms
Patients typically present with subclinical disease that is rarely fulminant. "Symptoms develop in only 20 percent of patients, and 10 to 20 percent of those have nonspecific symptoms," he noted. "Jaundice develops in 20 to 30 percent of symptomatic patients."
Certain lab results give clues to a diagnosis of HCV infection. HCV RNA can be detected in blood within one to three weeks after exposure to the virus, and elevations in ALT are present within four to 12 weeks. The average time from exposure to seroconversion is eight to nine weeks, and the average time from exposure to the development of symptoms is six to seven weeks, he said.
The highest prevalence rates are among 30- to 39-year-olds, Cassidy said. Prevalence is higher among men than women, especially among African-American men. An astounding 95 percent of HCV-infected African-American men become chronic carriers of hepatitis C, he said.
Hepatitis C is a progressive, fibrotic liver disease with a linear progression profile, Cassidy said. Patients may evidence slow, intermediate or rapid progression. Alcohol use and coinfections with hepatitis B or HIV increase the rate of progression, as do continued intravenous drug use and steatosis.
Treatment options
The current treatment options are either interferon given twice weekly with ribavirin or pegylated interferon alfa given once weekly with ribavirin. The goal of treatment is to prevent the infected patient from progressing to cirrhosis.
In addition to interferon and ribavirin therapy, all patients should be vaccinated for hepatitis A, and those who are not in monogamous relationships should be vaccinated for hepatitis B, Cassidy said. All patients should be counseled to avoid alcohol, lose weight, and avoid NSAID and aspirin use. Cirrhotics should receive flu and pneumococcus shots every year, and they should avoid contact with stagnant water, which can expose them to hepatitis A.
Patients should respond to drug therapy within 12 weeks of administration, but if there is no response within that time, stop giving the drugs, Cassidy said.
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