Acute otitis media as complication after treatment with rituximab for anti-NMDA receptor encephalitis

Abstract

Introduction: Anti-NMDA receptor encephalitis is characterized by a predictable set of neurological and psychiatric symptoms. Diagnosis is confirmed by the detection of IgG antibodies against NMDA receptor. Treatment options include administration of methylprednisolon and immunoglobulin G with or without rituximab. Methods: We report the case of a 19-year-old patient with a persistent right-sided otorrhea, otalgia and hearing loss. Laboratory work-up showed moderate CRP increase and leukocytosis. Physical examination revealed retroauricular erythema and tenderness. There was a history of prolonged treatment with rituximab due to anti-NMDA receptor encephalitis. Results: Because of a deterioration despite conservative management, mastoidectomy was performed. Postoperatively a severe wound dehiscence was observed. Suspecting a systemic cause, supplementary cytological and immunological analyses were conducted that revealed a severe reduction of B-cells. The previous treatment with rituximab was considered responsible. Immunoglobulin was administered and secondary wound closure with tympanoplasty and a canal-wall-down mastoidectomy was performed. Discussion: Acute otitis media may constitute the only manifestation of a systemic disease. Furthermore, a severe wound dehiscence under antibiotics in young, otherwise healthy individuals should raise suspicion of systemic cause and should lead to further diagnostic evaluation. Precise history taking and interdisciplinary approach are essential for the identification of the disorder and initiation of the appropriate treatment.