Anti-N-Methyl-D-Aspartate Receptor Encephalitis: A Potential Mimic of Neuroleptic Malignant Syndrome

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

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.

Spectrum of Anti-NMDA Receptor Antibody Encephalitis: Clinical Profile, Management and Outcomes

Background:

Anti-N-methyl D-aspartate receptor (anti NMDAR) antibody encephalitis is an immune-mediated entity characterised by a constellation of neuro-psychiatric symptoms.

Objective:

To describe clinical profile and treatment outcomes of patients with anti NMDAR antibody encephalitis.

Settings and Design:

Subjects were selected by screening for all patients satisfying Graus et al.'s criteria for probable anti NMDAR antibody encephalitis, admitted in neurology department of a tertiary care centre in Eastern India.

Materials and Methods:

A prospective, longitudinal study was conducted by identifying 25 patients with anti NMDAR antibodies in CSF and or serum, between September 2018 to February 2020.

Statistical Analysis:

Chi square test was used to compare variables.

Results:

Out of 98 patients screened, 25 subjects (14 females: 11 male) were positive for anti NMDAR autoantibodies, with a mean age of 17 years. 13 subjects belonged to paediatric age group. Most common presenting feature was memory/learning deficit (88%) followed by behavioural abnormalities (84%) and seizures (68%). 11 patients (44%) patients needed escalation to second line therapy, rituximab. Seven (28%) and twelve (48%) patients underwent complete (mRS 0-1) and partial recovery (mRS 2-3) respectively, while 4 (16%) became disabled (mRS 4-5). Mortality was 8%. Paediatric population had a better outcome in terms of disability (p = 0.043).

Conclusion:

Anti NMDAR-Ab encephalitis is the most common cause of antibody positive autoimmune encephalitis worldwide. There are important clinical markers and investigational profiles which carry prognostic significance.

Autoimmune encephalitis: clinical spectrum and management

Autoimmune encephalitis defines brain inflammation caused by a misdirected immune response against self-antigens expressed in the central nervous system. It comprises a heterogeneous group of disorders that are at least as common as infectious causes of encephalitis. The rapid and ongoing expansion of this field has been driven by the identification of several pathogenic autoantibodies that cause polysymptomatic neurological and neuropsychiatric diseases. These conditions often show highly distinctive cognitive, seizure and movement disorder phenotypes, making them clinically recognisable. Their early identification and treatment improve patient outcomes, and may aid rapid diagnosis of an underlying associated tumour. Here we summarise the well-known autoantibody-mediated encephalitis syndromes with neuronal cell-surface antigens. We focus on practical aspects of their diagnosis and treatment, offer our clinical experiences of managing such cases and highlight more basic neuroimmunological advances that will inform their future diagnosis and treatments.

Pediatric Anti-NMDA-R Encephalitis: Presentation, Diagnosis, and Management

Immune- mediated encephalitis is the most common cause of encephalitis after infection in children and adults. Although this disease process was identified nearly 20 years ago, the variety of clinical presentations and the lack of specific diagnostic criteria can make the identification of anti-N-methyl-D-aspartate receptors (NMDA-R) encephalitis challenging. Moreover, identifying NMDA-R antibodies in blood or cerebrospinal fluid can take days to weeks, and thus clinicians need to have a high index of suspicion to investigate for this disease in patients who may appear to have an overlap of neurologic and psychiatric symptomatology. In this article, the authors describe three illustrative cases of anti-NMDA-R encephalitis in children age 3 to 16 years. The discussion reviews our current understanding of the clinical presentation, diagnostic criteria, and inpatient therapeutic management of anti-NMDA-R encephalitis, as well as illuminates the unique and often perplexing presentations of this disease process versus other organic and psychiatric causes of altered mental status. [Pediatr Ann. 2019;48(10):e387-e390.].

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

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.