Disclosures: Linh Ngo, DO, MS: No financial relationships or conflicts of interest

Case Diagnosis: Autoimmune Limbic Encephalopathy

Case Description: 49-year-old male was diagnosed with herpes simplex virus type 1 encephalitis (HSE) and was treated with a 21-day course of intravenous acyclovir. He was discharged to an inpatient rehabilitation facility (IPR) with deficits most notably in cognition. Despite profound confusion and short-term memory loss, he progressed to supervision level with mobility. He continued to show severe memory deficits with difficulty with recall and inability to learn new tasks. He rapidly developed irritability, anxiety, and psychosis. He was transferred to acute care for further workup and management.

Setting: Inpatient Rehabilitation FacilityAssessment/

Results: Autoimmune limbic encephalitis (ALE) following HSE was the likely diagnosis. Cerebral spinal fluid (CSF) showed elevated white blood count of 18. T2- weighted magnetic resonance imaging (MRI) revealed extensive bilateral anterior temporal hyperintensities extending into the mesial inferior frontal lobes. Serum and CSF autoimmune encephalitis panels were negative; however sensitivity was presumed poor. He was subsequently treated with immunosuppression but his prognosis remained poor with little to no improvements.

Discussion: Short-term memory deficit is the hallmark of ALE but its diagnosis can be difficult. It can quickly progress to severe behavioral changes, anxiety, depression, psychosis, and seizures. ALE is often treatment responsive and delay to diagnosis and treatment are associated with a worse prognosis. Patients may have permanent neurologic sequelae of varying severity.

Conclusion: Evidence of mesial temporal signals on MRI, CSF with pleocytosis, and subacute memory deficits with behavioral changes should aid in the diagnosis of ALE. Early diagnosis and treatment are crucial as delays lead to a poor prognosis. It is especially important to monitor patients with HSV-1 encephalitis as there is an association with development of autoimmune limbic encephalitis.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/psychosis-and-neurosis-following-herpes-encephalitis-a-diagnosis-of-autoimmune-encephalitis/