In a pattern reminiscent of HAV, HEV RNA can be detected in stool and serum during the incubation period, with the subsequent appearance of the IgM and IgG anti-HEV antibodies. The sensitivity and specificity of available assays for anti-HEV (IgG- and IgM-specific assays) vary widely, which may account for the discrepancies among published rates of anti-HEV antibody in various populations. For example, a recent study reported anti-HEV positivity in 21% of serum samples obtained during the Third National Health and Nutrition Examination Survey, despite the absence of reported clinical HEV infection. This could represent false positivity or be truly reflective of a common asymptomatic infection. Nucleic acid tests for HEV RNA may soon be available.
Commercial tests for anti-HEV are becoming more widely available, and formal US Food and Drug Administration approval is pending. Thus, the diagnosis should be pursued if clinical suspicion is high, especially in immune-suppressed patients.
Studies conducted over the past 3 years have clarified the role of HEV in causing liver disease. Hepatitis E clinically resembles other forms of liver disease, including drug-induced liver injury.[10,18,19,20,21]
In acute hepatitis, fatigue, nausea, and jaundice characterize the early course, followed by elevations in serum alanine aminotransferase (ALT) levels. Chronic hepatitis E is characterized by persistence of HEV RNA in serum and excretion of the virus in stool. This is accompanied by fluctuating elevations in serum ALT levels.
Acute liver injury as a result of HEV may have a worse outcome when superimposed on preexisting chronic liver disease. Chronic HEV infection, with progression to cirrhosis, has been identified in immunocompromised persons (eg, organ transplant recipients).[1,2,8,10]
Medscape Gastroenterology © 2013 WebMD, LLC
Cite this: William F. Balistreri. Thickening the Alphabet Soup: The Emergence of Hepatitis E - Medscape - Apr 25, 2013.