Neuropsychiatric phenotypes of anti-NMDAR encephalitis: a prospective study.

BACKGROUND: Patients with anti-N-methyl-d-aspartate (NMDA) receptor encephalitis (ANMDARE) show a wide range of behavioral abnormalities and are often mistaken for primary psychiatric presentations. We aimed to determine the behavioral hallmarks of ANMDARE with the use of systematic neuropsychiatric and cognitive assessments. METHODS: A prospective study was conducted, with 160 patients admitted to the National Institute of Neurology and Neurosurgery of Mexico, who fulfilled criteria for possible autoimmune encephalitis and/or red flags along a time window of seven years. Cerebrospinal fluid (CSF) antibodies against the NR1 subunit of the NMDAR were processed with rat brain immunohistochemistry and cell-based assays with NMDA expressing cells. Systematic cognitive, neuropsychiatric, and functional assessments were conducted before knowing NMDAR antibodies results. A multivariate analysis was used to compare patients with and without definite ANMDARE according to antibodies in CSF. RESULTS: After obtaining the CSF antibodies results in 160 consecutive cases, 100 patients were positive and classified as having definite ANMDARE. The most frequent neuropsychiatric patterns were psychosis (81%), delirium (75%), catatonia (69%), anxiety-depression (65%), and mania (27%). Cognition was significantly impaired. A total of 34% of the patients had a predominantly neuropsychiatric presentation without seizures. After multivariate analysis, the clinical hallmarks of ANMDARE consisted of a catatonia-delirium comorbidity, tonic-clonic seizures, and orolingual dyskinesia. CONCLUSIONS: Our study supports the notion of a neurobehavioral phenotype of ANMDARE characterized by a fluctuating course with psychotic and affective symptoms, catatonic signs, and global cognitive dysfunction, often accompanied by seizures and dyskinesia. The catatonia-delirium comorbidity could be a distinctive neurobehavioral phenotype of ANMDARE.

[The clinical use of auto-antibodies in neurology]. / Uso clínico de autoanticuerpos en neurología.

INTRODUCTION: Auto-antibody determinations are very important in current clinical practice, not only in immunology or rheumatology but also in the neurosciences. These antibodies have both diagnostic and prognostic implications which, unfortunately, are often overused or are granted undue importance when it comes to interpreting them. On requesting their determination it is therefore necessary to know their indications, utility and application. AIM: To present a series of auto-antibodies that are relatively commonly used in neurology and which have primary and secondary effects on both the central and the peripheral nervous system, including the neuromuscular junction and muscle tissue. DEVELOPMENT: In this review we cover a series of different conditions, including diseases such as vasculitis, cerebrovascular disease, neurological paraneoplastic syndromes, dysimmune polyneuropathies and inflammatory myopathies. Special attention is given, when relevant, to the indications and, particularly, to the value and weight that should be granted to both positive and negative results. CONCLUSIONS: Appropriate interpretation and knowledge of the scope and limitations of auto-antibodies are essential, because otherwise they will lead to mistaken diagnoses and, consequently, erroneous treatment.