Clinical, Diagnosis And Therapeutic Aspects Of Anti-NMDAR Encephalitis

Anti- N-methyl- D- aspartate- receptor(NMDAR) encephalitis is an autoimmune disorder, often associate with paraneoplastic nature and disorder arises from the reaction of the immune system against neuronal cell surface of the central nervous system. Psychosis, prodromal syndrome, memory and language disturbance, neurological disturbance(seizures, decreased conscious level, dyskinesia, autonomic instability) are the main clinical features of anti- NMDAR encephalitis. It usually associated with ovarian tumors(70% benign) if female and relapse occurs if tumor is not removed. Conventional investigations like cerebrospinal fluid(CSF) exam, brain imaging and Electroencephalography(EEG) are non-specific for diagnosis of anti-NMDAR encephalitis. CT scans of the brain are usually normal. MRI of the brain may be normal or may demonstrate nonspecific abnormalities in the T2 weighted or FLAIR images. Brain imaging MRI is not sensitive to detect anti-NMDAR encephalitis but one third of patients show abnormalities. There is higher intensity in the cerebellar, cerebral cortex, hippocampus, frontobasal, insular areas and brain stem. The patient with NMDAR had extensive lesion in the basal ganglia, thalamus, hippocampus and cortex. Positron Emission Tomography(PET) Scan is more sensitive than MRI in NMDAR encephalitis. The scan demonstrated reduced fluorodeoxyglucose metabolism in the cerebral cortex, with the temporal region most affected. The acute NMDAR encephalitis indicated cortical hyper metabolism however cortical hypo metabolism may associate in relapsing NMDAR encephalitis. Immunotherapy including high dose corticosteroids and intravenous immunoglobulins is the first line therapy and half of the patients recovered by this therapy. Second line immune therapy including rituximab or cyclophosphamide is the drug of choice for those patients who do not recover by first. Early treatment is mandatory. Because the prognosis of these patients may be improved by early treatment although optimal treatment has not yet been discovered. The objective of this review focuses on challenges of diagnosis and therapeutic management of this disease.