Elderly‐onset acute necrotizing encephalopathy mimicking severe heat stroke: a case report and review of the literature

BACKGROUND: Acute necrotizing encephalopathy (ANE), known as influenza‐associated encephalitis, typically affects children. CASE PRESENTATION: A 70‐year‐old woman was admitted to the hospital with altered consciousness, a high temperature, and severe hypotension. Computed tomography (CT) of the head showed no abnormalities; thus, a diagnosis of suspected severe heat stroke was made. On day 2, repeated head CT revealed bilateral symmetrical lesions to the thalamus, and a rapid influenza antigen test was positive. Based on the CT findings and the medical history of influenza, a differential diagnosis of ANE was made. Subsequently, brain edema spread across the whole brain, and the patient died on day 21. CONCLUSION: In elderly patients, differentiating ANE from severe heat stroke in a high‐temperature environment is difficult because of the similarities in clinical symptoms due to multiple organ failure.