Hepatitis E

Hepatitis E virus (HEV) is a non-enveloped RNA virus, predominantly transmitted via the fecal-oral route (contaminated water in endemic regions, genotypes 1 and 2), though genotype 3 (the dominant genotype in high income countries) is a zoonotic infection acquired from undercooked pork, wild boar, or deer products, and can also be transmitted via blood transfusion.

Usually causes a self-limiting acute hepatitis similar to hepatitis A, but with two important distinguishing features: markedly increased mortality in pregnant women (particularly third trimester, with fulminant hepatitis rates up to 20 to 25% and high maternal mortality), and the capacity to cause chronic infection in immunocompromised patients (notably solid organ transplant recipients), a pattern not seen with hepatitis A.

Similar to hepatitis A: prodromal malaise, nausea, and anorexia followed by jaundice, dark urine, and pale stools, generally self-limiting over several weeks in immunocompetent, non-pregnant individuals.

Pregnant women, particularly in the third trimester, are at markedly elevated risk of fulminant hepatic failure.

Immunocompromised patients (particularly transplant recipients on immunosuppression) may develop chronic HEV infection with persistent viremia, progressive fibrosis, and, in some cases, extrahepatic manifestations (notably a range of neurological syndromes including Guillain-Barré syndrome and neuralgic amyotrophy, increasingly recognized as HEV-associated).

Anti-HEV IgM for acute infection; HEV RNA (PCR) is used to confirm active infection, particularly important in immunocompromised patients where serological response may be blunted or absent, and is essential for diagnosing and monitoring chronic infection (persistent viremia beyond 3 months).

LFTs as for any acute hepatitis.

• Immunocompetent, non-pregnant patients: supportive care only, as for hepatitis A, with spontaneous resolution expected
• Pregnancy: close monitoring given the significant fulminant hepatitis risk, with early involvement of hepatology and obstetric teams; management of established fulminant hepatic failure follows standard principles (see Acute Liver Failure entry), with delivery timing individualized
• Chronic infection in immunocompromised patients: reduction of immunosuppression is the first step where feasible, which achieves clearance in a proportion of cases; ribavirin (typically for 3 months, monitored with HEV RNA) is used for persistent infection not clearing with immunosuppression reduction alone
• Prevention: a hepatitis E vaccine is licensed and used in some endemic countries (notably China) but is not yet widely available globally; general prevention relies on safe water/sanitation in endemic settings and thorough cooking of pork products in genotype 3 endemic regions

Referral: hepatology for any immunocompromised patient (chronic infection management) or evidence of fulminant hepatitis; obstetrics for confirmed infection in pregnancy.