A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
A 33-year-old woman, gravida 2, para 1, at 24 weeks' gestation is brought to the emergency department by her husband for lethargy, nausea, and vomiting for 4 days. She returned from a trip to South Asia 2 weeks ago. Her immunizations are up-to-date and she has never received blood products. Her temperature is 38.9°C (102°F). She is not oriented to person, place, and time. Examination shows jaundice and mild asterixis. Her prothrombin time is 18 sec (INR=2.0), serum alanine aminotransferase is 3911 U/L, and serum aspartate aminotransferase is 3724 U/L. This patient's current condition is most likely associated with increased titers of which of the following serum studies?
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A
HBsAgIncorrect. HBV is parenterally/sexually transmitted; she denies blood products and is up-to-date on immunizations—HBV doesn't fit the travel and severity context.
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B
Anti-HEV IgMCorrect. HEV is fecal–orally transmitted in South Asia and causes fulminant hepatic failure with high mortality in pregnant women; anti-HEV IgM confirms acute infection.
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C
Anti-HCV IgGIncorrect. Anti-HCV IgG develops months after infection and HCV is parenterally transmitted; it doesn't fit the acute fulminant travel-related picture.
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D
Anti-HAV IgMIncorrect. HAV is fecal-orally transmitted and acute, but lacks the marked increased severity in pregnancy that distinguishes HEV.
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E
Anti-HBc IgMIncorrect. Anti-HBc IgM indicates acute hepatitis B infection, but HBV is parenterally and sexually transmitted; the fecal-orally acquired travel-related fulminant hepatitis in pregnancy fits HEV.
↑ Tap an answer to reveal the reasoning
Answer: B. A pregnant woman in the second trimester with fulminant hepatic failure (jaundice, encephalopathy with asterixis, INR 2.0, AST/ALT in the thousands) shortly after returning from South Asia has acute viral hepatitis E. Hepatitis E is transmitted enterically (fecal–oral, often via contaminated water) and is endemic in Asia, Africa, and Central America. Most cases of HEV are self-limited, but in pregnant women—especially in the second and third trimesters—HEV has a strikingly high case-fatality rate (up to 20%) due to fulminant hepatic failure. The diagnostic test is anti-HEV IgM.
Key distinctions:
- HAV (anti-HAV IgM) is also fecal-oral and acute, but does NOT have the dramatically increased severity in pregnancy that defines HEV.
- HBsAg (HBV surface antigen) marks acute or chronic HBV—transmitted parenterally/sexually, and this patient denies blood products; HBV is up-to-date immunized; this presentation would be unusual at this severity in pregnancy without HBV history.
- Anti-HCV IgG develops months after infection (HCV rarely causes acute fulminant hepatitis and is parenterally transmitted, not from contaminated water in Asia).
Management is supportive (transfer to a transplant center, manage hepatic encephalopathy/coagulopathy, fetal monitoring); there is no specific antiviral therapy for HEV beyond ribavirin in select chronic cases.
**Why each option:**
**A.** HBV is parenterally/sexually transmitted; she denies blood products and is up-to-date on immunizations—HBV doesn't fit the travel and severity context.
**B.** Correct. HEV is fecal–orally transmitted in South Asia and causes fulminant hepatic failure with high mortality in pregnant women; anti-HEV IgM confirms acute infection.
**C.** Anti-HCV IgG develops months after infection and HCV is parenterally transmitted; it doesn't fit the acute fulminant travel-related picture.
**D.** HAV is fecal-orally transmitted and acute, but lacks the marked increased severity in pregnancy that distinguishes HEV.