Anti-N-methyl-D-aspartate receptor encephalitis mimics neuroleptic malignant syndrome: case report and literature review

Abstract

Background

Anti-N-methyl-D-aspartate (anti-NMDA) receptor encephalitis is a severe autoimmune disease characterized by complicated psychiatric and neurological symptoms and a difficult diagnosis. This disorder is commonly misdiagnosed, and diagnosis is often delayed. The clinical signs can mimic other psychiatric abnormalities, such as neuroleptic malignant syndrome (NMS) that is usually caused by antipsychotic exposure. This fact raises the question of whether the symptoms common to NMS are due to anti-NMDA receptor encephalitis or established NMS.

Cases presentation

We describe a rare case of a 29-year-old male without psychiatric history who initially presented with a fever, altered consciousness, behavioral changes, rigidity, and elevated creatine kinase. He was initially diagnosed with NMS. NMS-like symptoms did not improve with active treatments and disappeared for a long period after discontinuing antipsychotics. The patient gradually developed a complicated disease progression, including speech impairment, mutism, and movement disorders, and symptom progression led to the final diagnosis of anti-NMDA receptor encephalitis. The related pathophysiological mechanisms, clinical features, and treatment of this disease are reviewed.

Conclusion

We highlight that the natural progress of anti-NMDA receptor encephalitis can mimic the symptoms of NMS and NMS-like features could be due to anti-NMDA receptor encephalitis upon antipsychotic exposure, and not true NMS. Clinically, the suspicion of NMS may serve as a significant alarm to suspect anti-NMDA receptor encephalitis and lead neurologists or psychiatrists to investigate such a diagnosis.

Keywords:

• acute psychosis
• anti-NMDA receptor encephalitis
• autoimmune encephalitis
• neuroleptic malignant syndrome
• antipsychotics
• diagnosis

Acknowledgments

We appreciate Professor Bingwei Zhang (Department of Neurology and Psychiatry, First Affiliated Hospital of Dalian Medical University) very much for his constructive suggestions on our manuscript.

Author contributions

HYW wrote the manuscript. HYW, TL, XLL, and YX actively participated in the data acquisition and prepared the table. HYW, XXZ, ZRY, and YX reviewed the literature and participated in data interpretation. All authors contributed to the final manuscript review and editing. All authors contributed to data analysis, drafting or revising the article, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.