Case Presentation: A 19-year-old Caucasian female with hypothyroidism on synthroid was transferred from an outside emergency department for evaluation of psychosis. The patient’s father first noted changes in her behavior several months prior to admission when she developed rapid onset of excessive cleaning and organizing behavior, which was inconsistent with her prior messy behavior.  In the week prior to presentation, the patient became increasingly forgetful, would isolate herself from others due to paranoid delusions, began experiencing auditory hallucinations and repetitively removed her clothes and put them back on inside-out. There was no history of intoxicant use. On exam, vital signs were unremarkable, the patient had blue-dyed hair, appeared disheveled, and had repetitive hand and oral movements (protrusion of tongue, distortion of mouth, and lip smacking). There were no focal neurological deficits and the remainder of her physical exam was unremarkable. Workup for metabolic, infectious, and toxic etiologies was negative. ANA was noted to be positive at 1:160. MR of the brain revealed no intracranial abnormalities. Initial suspicion for a primarily psychological etiology was high, however a lumbar puncture was sought to complete her evaluation.  Prior to this, the patient developed generalized seizure like activity that resolved with Ativan administration.  EEG showed no epileptiform activity but was consistent with encephalopathy. Analysis of CSF showed RBC of 2 and WBC of 44 with 96% lymphocytes. CSF gram stain, culture, and viral studies were negative.  The presence of anti-N-Methyl-D-Aspartate (NMDA) receptor antibodies was confirmed in the CSF at a titer of 1:32. The patient was treated with intravenous immunoglobulin, high-dose steroids, and cyclophosphamide. Evaluation for ovarian neoplasm was negative.  With treatment, the patient markedly improved and went on to make a full recovery.

Discussion: The evaluation of new onset psychosis involves a structured approach that includes evaluating for metabolic, infectious, toxic and autoimmune etiologies. Hospitalists are at risk for premature closure by settling on a diagnosis of psychiatric illness too early in the evaluation of such patients. First described in 2007, Anti-NMDA receptor encephalitis typically presents with auditory and visual hallucinations, delusions, dyskinesia, and possibly seizures. Approximately 80% of cases are found in females, with half of these being associated with ovarian teratomas.

Conclusions: Anti-NMDA encephalitis is becoming increasingly recognized as a cause for neuropsychiatric symptoms, particularly in women. Hospitalists need to be aware of this relatively newly identified and potentially treatable disease. In a patient with new-onset psychosis, seizure like activity, and dyskinesia, a high degree of suspicion must be maintained to make an early diagnosis.