Tuesday, June 06, 2006
Chronic VS. Acute Hepatitis C infection
Acute Hepatitis C infection is the period of time that begins with the intial infection, and includes the incubation period and the possible appearance of clinical illness. Because the hepatitis C virus has the ability to evade the immune response in many people, about 85 percent of patients with acute HCV infection develop persistent infection. Chronic hepatitis C, defined as persistently elevated alanine aminotransferase (ALT) levels more than 6 months after illness onset, develops in about 70 percent of cases.
Symptoms of Acute HCV Infection
Not everyone infected with the hepatitis C virus has symptoms of infection. Studies have shown that 60 to 70 percent of patients with acute HCV infection have no discernable symptoms. Approximately 20 to 30 percent of patients may be ill with jaundice. About 10 to 20 percent of acutely infected people have vague and non-specific symptoms that can be can be easily mistaken for other illnesses. When present, symptoms have been described as "flu-like" and can include: Fatigue: a feeling of weariness of exhaustion. Liver pain: discomfort or tenderness in the upper right quadrant of the abdomen, which may be associated with enlargement of the liver .Nausea and decreased appetite,
Pain in muscles and joints.
When patients with acute HCV infection seek medical attention, about 80 percent have elevated levels of bilirubin and alanine aminotransferase (ALT). Only about 15 percent of patients require hospitalization. In rare cases, HCV infection can cause fulminant hepatic failure. This complication is more likely to occur when patients have other diseases that impair their immune systems, such as HIV, or have pre-existing liver disease.
HCV Incubation and the Appearance of Symptoms
Incubation is the period of time between exposure and infection, and the manifestation of the disease. The incubation period for newly acquired acute hepatitis C ranges from two weeks to six months, with an average incubation period of six to seven weeks. Blood tests can detect the presence of the HCV virus in blood after 1 to 3 weeks of infection. By the time symptoms appear, 70 to 80 percent of patients have detectable antibodies to HCV. HCV antibodies can be detected in about 90 percent of infected people by 3 months after the appearance of symptoms. Ultimately, HCV antibodies become detectable in over 95 percent of HCV-infected persons. Although the period of acute HCV infection is variable, one of the more prominent characteristics features is fluctuating blood levels of alanine aminotransferase, sometimes by hundreds of units per week. Over time, ALT levels can return to normal, but may later be followed by prolonged, symptomless ALT elevations indicating active chronic disease.