Extra-Hepatic Manifestations of Hepatitis E Virus (HEV): A Narrative Review on Meningoencephalitis

Hepatitis E virus (HEV) infection, once regarded as a self-limiting hepatic disease confined to endemic regions, is now recognized as a systemic condition with a broad spectrum of extrahepatic manifestations. Among these, neurological complications-including peripheral neuropathies such as Guillain-Barré syndrome and neuralgic amyotrophy, and central nervous system involvement such as meningitis, encephalitis, and meningoencephalitis-are the most clinically relevant. Meningoencephalitis, though less common, is the most severe and underdiagnosed neurological expression of HEV infection. This narrative review examines current evidence on HEV-associated meningoencephalitis, covering epidemiology, pathogenesis, clinical features, and therapeutic strategies. Neurological disease is dominated by genotype 3 and frequently anicteric, with symptoms preceding or masking hepatic involvement. Pathogenesis is multifactorial, combining direct viral neurotropism-supported by HEV RNA detection in cerebrospinal fluid and replication in induced pluripotent stem cell (iPSC)-derived neurons and brain organoids-with immune-mediated mechanisms such as molecular mimicry and microglia-driven neuroinflammation. Diagnosis is often delayed by the absence of jaundice and low clinical suspicion, even though HEV remains an unrecognized cause in many unexplained encephalitis cases in high-income settings. Ribavirin remains the antiviral mainstay, but viral persistence within CNS sanctuary sites raises concerns about treatment adequacy and relapse; emerging antiviral and immunomodulatory strategies remain under investigation. HEV should be systematically considered in the diagnostic workup of unexplained neurological syndromes, regardless of overt hepatitis; heightened clinical awareness remains the most immediately actionable step toward reducing the burden of this still under-recognized condition.