Kayla M. Hamilton, BFA; Sommer D Zarbock, PharmD, RPh

Presbyterian/St. Luke-Rocky Mountain Hospital for Children

ASHP Poster Abstract, October 2018

 

We report a case of a pediatric patient who developed a rare finding of suspected anti-N-methyl-D-aspartate receptor autoimmune encephalitis that was treated successfully with high-dose intravenous corticosteroids. The patient is an eight-year-old female that was admitted to the pediatric floor for status epilepticus after a week of fever and emesis, as reported by the patient’s mother. The patient was treated with: fosphenytoin 500 mg IV, lorazepam 2.5 mg IV, midazolam 1 mg IV, phenobarbital 500 mg IV, and valproate 1,200 mg IV for seizures, and the seizure activity was resolved. She was transitioned to divalproex 200 mg orally every 12 hours and levetiracetam 630 mg orally every 12 hours. Previous to being discharged home, she began to have more seizure-like activity, despite the anti-epileptic medications, and was witnessed to have unsteady ambulation and abnormal behavior, including hallucinations and altered speech. EEG showed seizures originating from both the right and left temporal regions. A lumbar puncture was unremarkable, but a sample was sent for anti-NMDA receptor antibody testing. MRI showed abnormal signals from the supratentorial cortex. It was noted by the neuroradiologist that, although rare, anti-NMDA receptor autoimmune encephalitis can present with similar image findings. The patient was immediately treated with high-dose methylprednisolone 342 mg IV every 12 hours for five days, approximately 30 mg/kg. Within the first day of treatment, she began to show rapid signs of improvement. By the end of her treatment, all seizures had ceased and the patient was walking independently. The patient was discharged home on oral prednisolone 60 mg once daily on a six-week taper schedule. The definitive test for anti-NMDA receptor autoimmune encephalitis is NMDA-receptor antibodies in the cerebrospinal fluid. Since the test for the antibodies can be returned weeks after the assay is ordered, a suspected diagnosis should be based on other findings, such as abnormal MRI scans, EEG results, or behavior patterns. A viral-like prodrome of fever and emesis can also direct suspicion toward anti-NMDA receptor autoimmune encephalitis. This case report highlights the potential benefits of administering high-dose IV corticosteroids to pediatric patients who present with a virus-like prodrome, abnormal behavior, and refractory new-onset seizures on the suspicion of anti-NMDA receptor autoimmune encephalitis.