Neuroleptic Malignant Syndrome in a Patient With Anti-N-Methyl-D-Aspartate Receptor Encephalitis: Case Report and Review of Related Literature

Abstract

Introduction: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a severe but treatable disease that presents with symptoms similar to neuroleptic malignant syndrome (NMS). Case Report: We describe a 28-year old female who initially presented with headaches, behavioral changes, anxiety, lip tremors, and rigidity of extremities. She was prescribed with olanzapine and later manifested with neuroleptic malignant syndrome symptoms such as decrease in sensorium, muscle rigidity, hyperthermia and tachycardia. Further investigation showed presence of bilateral ovarian teratoma and anti-NMDAR antibodies in her serum and cerebrospinal fluid. Symptoms resolved after intravenous high-dose methylprednisolone, bilateral oophoro-cystectomy, and intravenous immunoglobulin administration. Overlapping pathological mechanisms of anti- NMDAR encephalitis and NMS were discussed. Ten patients with anti- NMDAR encephalitis and NMS were noted in a review of literature. Prognosis was favorable and intervention ranged from supportive to methylprednisolone and intravenous immunoglobulin administration, plasma exchange and teratoma resection. Conclusion: Anti- NMDAR encephalitis patients are at risk for NMS due to antipsychotic intolerance and other interrelated pathophysiological mechanisms. The overlap between the signs and symptoms of anti-NMDAR encephalitis and NMS poses a diagnostic dilemma and warrants a careful investigation and management.

Neuroleptic intolerance in the context of anti‐N‐methyl‐D‐aspartate receptor encephalitis: A systematic review and synthesis of global case reports

“…The reasons for exclusion are presented in Appendix S1. Finally, 22 records (containing the present case) were included 6,21–40 . Only cases where NI was suspected were included from the case series.…”

“…Forty patients presented with NI during confirmed anti‐NMDAR encephalitis (Table 2). 6,21–40 28 (70%) were female and the mean age of the sample was 24.6 (SD, 9.42; range 10–61) years old. However, nine patients were <18 years old (22.5%).…”

“…Finally, 22 records (containing the present case) were included. 6,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] Only cases where NI was suspected were included from the case series. For the included observational study, the cases reporting signs and symptoms suspicious of those complications were included, and individuals labeled as 5, 7, and 18 of the 21 patients were excluded for having symptoms different from the DSM-5 criteria.…”

“…Of the six cases, all reported that the investigation for the encephalitis happened during the treatment of the NI. 30,[33][34][35]39 Of the previously introduced clinical scenarios, three patients presented initially with NDMAR encephalitis and all developed NI during hospitalization (scenario 1). 26,29,37 None of these patients had a past medical history of neurological or psychiatric illnesses.…”

“…23,40 Additionally, in two of these patients, this initial presentation of NI triggered the diagnosis of anti-NDMAR encephalitis. 35,39 Scenario 3 was the most frequent (n = 28, 70%), which included an initial presentation marked solely by psychiatric symptoms. As such patients were admitted and treated psychiatrically and then later presented with features of NI and NMDA encephalitis.…”