Herpes Encephalitis as a Differential Diagnosis of Atypical Intracerebral Hemorrhage: A Case Series and Systematic Review.

Herpes simplex virus encephalitis (HSVE) is the most common infectious encephalitis and is associated with high morbidity and mortality when not treated in time. Symptoms include fever, headache, fatigue, neurological deficits such as aphasia and epileptic seizures. While hemorrhagic transformation is a common complication in HSVE, intracerebral hematoma (ICH) as the initial or main presentation is rare. We present two patients with HSVE who displayed a large temporal hematoma as the main finding on cerebral imaging. We further conducted a systematic literature review to identify all published cases of ICH in HSVE. Forty-nine publications met the inclusion criteria, describing a total of 55 patients. In 38 of these, HSVE could be definitely confirmed by brain biopsy, autopsy or PCR. We analyzed these cases according to age, gender, lag from symptom onset to hospital admission, lag from hospital admission to detection of hemorrhage, location of encephalitis and hemorrhage, received treatment and outcome. With a median age of 45 years, this cohort is significantly younger than general HSVE populations described previously. In conclusion, our review shows that, albeit rare, awareness about ICH complicating HSVE is highly relevant as failure to recognize an atypical course of HVSE may result in a delay of effective antiviral treatment, which is related to an unfavorable or even fatal outcome.