RT Journal Article SR Electronic T1 Herpetic encephalitis with autoimmune recurrence following cerebral aneurysm clipping JF BMJ Case Reports JO BMJ Case Reports FD BMJ Publishing Group Ltd SP e248896 DO 10.1136/bcr-2022-248896 VO 17 IS 11 A1 Moniz Dionísio, Joana A1 Santos, Mariana A1 Seromenho-Santos, Alexandra A1 Reizinho, Carla YR 2024 UL http://casereports.bmj.com/content/17/11/e248896.abstract AB A man in his late 60s with well-controlled HIV underwent an uneventful surgical clipping of an unruptured intracranial aneurism. Postoperatively, he developed fever, seizures and an altered mental status. Cerebrospinal fluid (CSF) showed lymphocytic pleocytosis, high protein count and a positive herpes simplex virus (HSV)-2 PCR. Acyclovir was started. Brain MRI showed right hemisphere T2/FLAIR-weighted anterior temporal cortical and subcortical hyperintensities. After 2 months, he developed psychosis, an upper limb tremor and pyramidal tract dysfunction. A new brain MRI revealed a new right frontal white matter lesion, extending to the corpus callosum. Anti-N-methyl-D-aspartate receptor (NMDAR) antibodies were positive in CSF, while there was no evidence of active HSV infection. Methylprednisolone and IVIg were started, and a significant clinical improvement was achieved.If an unknown inflammatory process occurs after surgery, herpetic encephalitis should be considered, and treatment should be initiated precociously. Since herpetic encephalitis can trigger an anti-NMDAR encephalitis, this autoimmune complication must be considered.