Resident Physician Overlook Medical Center, United States
Introduction: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is an auto-immune condition that can be lethal if not treated in a timely manner. It is frequently misdiagnosed because of the similarities in presentation with other psychiatric, neurologic, or infectious pathologies clinical presentations. Mortality rates have been estimated as being between 5 to 11%.
Description: A 30-year-old female presented with auditory hallucinations and flu-like symptoms. She was febrile but hemodynamically stable. Physical exam was unremarkable. Initial serum lab values showed a mild elevation in WBCs and inflammatory markers. CT head and MRI brain were without any acute or chronic findings. A CSF analysis was significant for an elevated WBC count with a lymphocytic predominance and high glucose with a negative meningitis panel. Continuous video electroencephalograph monitoring showed no seizure activity. The patient was started on broad-spectrum antibiotics as well as anti-psychotic medications to try to cover for both infectious and psychiatric etiologies. Despite this, the patient had persistent high-grade fevers. On day 5, she became obtunded and was intubated for airway protection. A CT of the abdomen was done to investigate for possible sources of infection, and ultimately revealed an ovarian dermoid. The suspicion for autoimmune encephalitis in the setting of an ovarian dermoid was high, and the patient was started on IVIg and systemic steroids. The patient underwent an oophorectomy with the pathology revealing a mature teratoma. CSF studies eventually returned positive for antibodies against NMDA receptors. With removal of the teratoma and treatment with IVIg and steroids, the patient showed signs of clinical improvement and was able to return to her baseline.
Discussion: NMDAR encephalitis predominantly affects young women and children and is associated with various tumors such as teratomas. Typically, patients present with nonspecific symptoms which rapidly progress to mental disturbances, seizures, decreased consciousness, involuntary movements, autonomic dysfunction, and respiratory depression. Herein, we highlight that diagnosing and treating NMDAR encephalitis in a timely manner is of paramount importance. A missed diagnosis can be lethal, however, early treatment has a promising prognosis.
