Successful Treatment of Refractory Dyskinesia Secondary to Anti-N-Methyl-D-Aspartate Receptor Encephalitis With Electroconvulsive Therapy.

To the Editor: A nti-N-methyl-D-aspartate (NMDA) receptor encephalitis is an autoantibodymediated neurological disease characterized by psychiatric symptoms, altered consciousness, cognitive dysfunction, autonomic instability, and seizures. It is well known that most patients with anti-NMDA receptor encephalitis respond to immunotherapy. However, a small proportion of patients did not respond to immunotherapy and resulted in severe neurological deficit or death. Furthermore, the treatment for patients with immunotherapy-resistant encephalitis has not been established. To the best of our knowledge, we report the first case of antiNMDA receptor encephalitis with prolonged and refractory dyskinesia, which was not improved by intensive immunotherapy and tumor removal but remarkably responded to electroconvulsive therapy (ECT). A 27-year-old woman, who was previously healthy with no history of psychiatric illnesses, complained of headache and insomnia. For a few days, confusion, visual and auditory hallucination, and disorganized speech developed. Then, she was referred to our institute 10 days after the symptom onset because of the aggravation of psychotic symptoms followed by decreased consciousness. At the time of the emergency room visit, she was observed to be semicomatosewithout focal or lateralized signs in neurologic examination. Laboratory tests showed leukocytosis (white blood cell counts, 16,120/μL)with increased segmented neutrophils (83.5%). Electrolyte panel demonstrated mild hyponatremia (130 mmol/L) with a low serum osmolality (278 mOsm/kg). Other blood test results including liver function tests and serum creatinine level were normal. Cerebrospinal fluid (CSF) study revealed pleocytosis (59/mm) with lymphocytic predominance (89.8%),whereas protein and glucose levels were within reference limits. We tested for an extensive list of infectious pathogens including herpes simplex virus, but results were all negative. Brain magnetic resonance imaging with contrast enhancement was unremarkable. At the day of the admission, we tested neuronal autoantibodies from CSF and blood samples. A computed tomography scan of the abdomen and pelvis demonstrated 2-cm-sized, low-attenuated lesion suggesting ovarian