Overview of Hepatitis

We now know that the Hepatitis C virus causes most infections formerly attributed to hepatitis non-A, non-B. Transmission is by exposure to blood in 50% of cases.

Before 1989, transfusion with blood or its products was the chief cause of blood-borne infection. But since that year, all donated blood has been screened for Hepatitis C, and this mode of transmission has virtually disappeared. Needle- stick injuries in health professionals are still a route to infection. Sharing of needles by drug abusers is also a major method of blood-borne transmission. French researchers P. Marcellin et al have found that homosexual transmission of Hepatitis C is relatively uncommon. They found the prevalence of infection was 5.3% among homosexual men with chronic hepatitis.

The 50% of Hepatitis C infections not caused by infected blood are called sporadic or community- acquired. How they are contracted remains a mystery. Some investigators have found that there may be an increased risk of community-acquired Hepatitis C infection in lower socioeconomic classes or in people with infected household contacts.

Detecting Hepatitis C virus has become much easier in the past few years. Although the virus has never been isolated, its genetic makeup has been fully described. This knowledge has allowed the preparation of synthetic peptides. These can detect the presence in serum of virus antibodies, known collectively as anti-HCV.

Tests for anti-HCV have improved greatly even in the short time they’ve been available. Current tests, such as the second-generation ELISAs and the so-called RIBA III test, are accurate, with much lower false-negative and false-positive rates than the original tests. This is because the newer assays have additional antigens. Now the greatest limitation of the assays may be the delayed appearance of anti-HCV after the initial infection.

Baskin et al suggest that RIBA testing is most helpful when ELISA results are intermediate or only weakly positive. The RIBA may not be needed when ELISA testing is strongly positive. But other authors feel that all ELISA assays need confirmation with the RIBA.

Anti-HCV testing is crucial for early detection, because acute Hepatitis C infection is usually mild. Although liver-enzyme measurements taken during the initial illness can be up to ten times the normal level, sometimes they are normal.

However, in a recent New England Journal article, Albert Czaja calls chronic Hepatitis C infections both indolent and sinister, because serious effects can be missed when follow-up is shorter than ten years. For instance, in one 30- month study of post-transfusion hepatitis, spontaneous improvement was common. In a bigger series of patients followed for six years, 54% had spontaneous remissions within three years. Most of those who went into remission were asymptomatic and had no cirrhosis. Deaths were rare, and the researchers found no hepatoma.

But something ominous happened when follow-up was at least ten years: there were many reports of late-onset cirrhosis, liver failure, and hepatoma. Several authors have stressed that long-term follow-up of asymptomatic patients is vital, because the Hepatitis C virus may persist indefinitely.

Even mild infection can lead to long-term inflammatory activity and eventual cirrhosis. About 50% to 80% of people with Hepatitis C develop cirrhosis, although for most this process takes as long as 20 to 30 years. About 5% of Hepatitis C carriers have more aggressive disease, which results in cirrhosis and liver failure within three to five years.

The most serious disease associated with Hepatitis C is hepatoma, which affects only patients with cirrhosis. Surgical resection is the treatment of choice, but it’s appropriate for only a small minority of patients. Detection is generally late and the prognosis very poor, with death occurring within months. Fortunately, Hepatitis C patients without cirrhosis are not at risk for hepatoma.