Disclosures: Alyssa M. Volmrich, MD, MBA: No financial relationships or conflicts of interest

Case Diagnosis: Prolonged Mutism secondary to Autoimmune Encephalitis

Case Description or Program Description: A 17-year-old previously healthy straight-A female presented with headaches, altered taste, and hearing disturbances. Encephalopathy autoimmune serum panel revealed N-Methyl-D-Aspartate (NDMA) antibody and Anti-Glutamic Acid Decarboxylase (GAD) antibody, consistent with anti-NMDA receptor encephalitis, and neoplastic syndromes were excluded. Her hospital course was complicated by respiratory depression requiring tracheostomy, dysphagia requiring G-tube placement, generalized weakness, abnormal movements, and mutism. As such, she underwent multiple courses of intravenous solumedrol, intravenous immunoglobulin G, plasmapheresis, rituximab, and cyclophosphamide.

Given her significant functional decline, she was transferred to acute inpatient rehabilitation. During her course, she demonstrated decrease in abnormal movements, improvements in strength, tolerance of oral diet, and resolution of supplemental oxygen requirements. However, the mutism persisted.

Setting: Inpatient Rehabilitation at a Public Trust Pediatric Hospital

Assessment/Results: The patient was admitted to inpatient rehabilitation for 22 days. Initially, there were discussions about trialing patient on bortezomib due to her severe and refractory course. However, with consistent therapy she improved to minimal assistance for expression by discharge. Two months later, at her outpatient follow-up, she exhibited the ability to verbalize and participate in a thorough neuropsychological examination. As such, additional pharmacological interventions were not provided and costly medication trials along with the potential adverse reactions were avoided.

Discussion (relevance): Catatonic symptoms, like mutism, have been well-documented in anti-NMDA receptor encephalitis and felt to be related to NMDA receptor dysfunction. Unlike the other symptoms commonly associated with autoimmune encephalitis, mutism can take longer to resolve. With patience and determination as well as inpatient rehabilitation and appropriate therapy, mutism can improve as well.

Conclusions: Residual mutism after anti-NMDA receptor encephalitis can be debilitating. However, with consistent rehabilitation therapy, patients can progress and avoid the need for costly medications and their potential side effects.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/lets-talk-about-it-a-case-report-of-residual-mutism-after-autoimmune-encephalitis/