(See also Causes of Hepatitis, Overview of Acute Viral Hepatitis, and Overview of Chronic Hepatitis.)
Hepatitis D is usually transmitted by parenteral or mucosal contact with infected blood or body fluids. Infected hepatocytes contain delta particles coated with hepatitis B surface antigen (HBsAg).
Prevalence of hepatitis D virus (HDV) varies widely geographically, with endemic pockets in several countries. Parenteral drug users are at relatively high risk, but HDV, unlike hepatitis B virus (HBV), has not widely permeated the homosexual community.
Symptoms and Signs
Acute hepatitis D infection typically manifests as
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Unusually severe acute HBV infection (coinfection)
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An acute exacerbation in chronic HBV carriers (superinfection)
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A relatively aggressive course of chronic HBV infection
Diagnosis
In the initial diagnosis of acute hepatitis, viral hepatitis should be differentiated from other disorders causing jaundice (see figure Simplified approach to possible acute viral hepatitis ). If acute viral hepatitis is suspected, the following tests are done to screen for hepatitis viruses A, B, and C:
If serologic tests for hepatitis B confirm infection and clinical manifestations are severe, antibody to HDV (anti-HDV) levels should be measured. Anti-HDV implies active infection. It may not be detectable until weeks after the acute illness.
Treatment
No treatments attenuate acute viral hepatitis, including hepatitis D. Alcohol should be avoided because it can increase liver damage. Restrictions on diet or activity, including commonly prescribed bed rest, have no scientific basis.
For cholestatic hepatitis, cholestyramine 8 g orally once or twice a day can relieve itching.
The only drug approved for treatment of chronic hepatitis D is interferon-alfa, although pegylated interferon-alpha is likely equally effective. Treatment for 1 year is recommended, although whether longer treatment courses are more effective has not been established. Hepatitis D is also treated in the context of clinical trials.
Prevention
No product exists for immunoprophylaxis of hepatitis D. However, prevention of HBV infection prevents HDV infection.
