Assistant Professor University of Arkansas for Medical Sciences Little Rock, Arkansas, United States
Case Diagnosis: Paraneoplastic Anti-N-methyl-D-aspartate Receptor Encephalitis
Case Description: A 27 year old healthy female presented to the emergency department (ED) with tremor, at which time workup was unremarkable and the patient was discharged home. She returned to the ED one week later with dizziness and new-onset generalized seizures. Initial lab workup and imaging were unremarkable. EEG confirmed epileptiform activity. One day after admission the patient developed paranoia, anxiety, blurred vision, dysphagia, ataxia and urinary retention as well as impaired attention, concentration and memory which prompted further investigation. Subsequent lab workup revealed the patient’s cerebrospinal fluid was positive for N-methyl-D-aspartate (NMDA) receptor antibody. This triggered imaging of the abdomen and pelvis which revealed a left ovarian teratoma nearly a week after initial onset of tremor. Following management with intravenous (IV) steroids, IV immunoglobulin and left salpingo-oophorectomy, the patient’s condition stabilized. She was admitted to acute inpatient rehabilitation for intensive comprehensive therapies where she made significant improvement.
Discussions: NMDA receptor is a glutamate receptor found in neurons that plays an important role in synaptic plasticity, memory and learning. Tumor development, most commonly ovarian teratomas in young black women, can lead to a paraneoplastic syndrome characterized by antibody formation against NMDA. In addition to the symptoms described in this case, patients may present with headache, fever, memory impairments, language disintegration, insomnia, dyskinesias and dysautonomia. In severe cases, symptoms may progress to catalepsy or a state of unresponsiveness. This condition, affecting one in 1.5 million people annually, is often mistaken for delirium or another mental illness. Definitive treatment includes surgical resection of the tumor. Relapse occurs in 15-24% of patients, sometimes years after initial presentation.
Conclusions: Paraneoplastic anti-NMDA receptor encephalitis is a rare and often delayed diagnosis which can postpone appropriate care including acute inpatient rehabilitation. Outcomes can be improved by diagnosing and treating the condition as quickly as possible.