Neuromyelitis Optica Spectrum Disorders Presenting with Area Postrema and Acute Brainstem Syndromes with Concomitant Myasthenia Gravis (P6.405)

Objective: To report a case of neuromyelitis optica spectrum disorders (NMOSD) in a patient who presented with severe hiccoughs, nausea, and vomiting with an isolated MRI abnormality in the area postrema. The case is rare as the patient presented with concomitant onset of two autoimmune disorders, NMOSD and myasthenia gravis (MG). Background: NMOSD is an inflammatory demyelinating disorder of the CNS, characteristically presenting with optic neuritis and longitudinally extensive spinal cord lesions. NMOSD lesions have a variable appearance and can mirror the periventricular distribution of AQP4, although isolated involvement of the brainstem is unusual. Design/Methods: We report a 64 year old female with a history of frontal meningioma resection who presented with subacute onset of intractable hiccoughs, severe nausea, and vomiting. Extensive GI workups including esophagram, gastric emptying study, CT of the abdomen, and GI endoscopy were unrevealing. The patient then developed ataxic gait, horizontal diplopia, ptosis, gaze evoked nystagmus and was referred for neurological evaluation. Results: Brain MRI two months after the symptom onset showed subtle FLAIR hyperintensity in the area postrema of the dorsal medulla, initially felt to be inconsequential. A repeat brain MRI three months later demonstrated progression of dorsal medullary signal abnormality, with differential diagnoses including NMOSD and Wernicke’s encephalopathy. Laboratory testing confirmed positive serum AQP4 antibody and normal Thiamine level. MRI of the brain, cervical and thoracic spine did not reveal additional NMOSD lesions. Interestingly, Acetylcholine receptor binding antibodies were positive, explaining her ocular symptoms. Conclusions: This case highlights the importance of including NMOSD in differential considerations in patients with isolated abnormalities in the dorsal medulla who presented with hiccoughs and nausea. This unique case demonstrates evolving medullary pathology on MRI. This is first reported case where a patient presented with concomitant symptomatic onset of NMOSD and MG, supporting shared autoimmune dysfunction. Disclosure: Dr. Schachter has nothing to disclose. Dr. Du has nothing to disclose. Dr. Tang has nothing to disclose.