Seronegative Neuromyelitis Optica Spectrum Disorder: An Unusual Presentation of Acute Brainstem Syndrome

BACKGROUND: Neuromyelitis optica (NMO) is an autoimmune, demyelinating, inflammatory disorder affecting the central nervous system, mostly targeting optic nerves and the spinal cord. NMO spectrum disorder (NMOSD) is a newly revised nomenclature in which new diagnostic criteria have been developed, including serological testing of serum aquaporin-4 immunoglobulin G (AQP4-IgG) antibodies. Results of a negative antibody will group the patient in a seronegative subgroup.
CASE REPORT: We describe the case of a 27-year-old female who presented to our hospital with new onset of sudden unexplained vomiting, dysphagia, dysphonia, and food regurgitation. Extensive investigations were done and brain magnetic resonance imaging (MRI) showed a small nonspecific area of signal abnormality in the right dorsal medulla. Aquaporin-4 antibodies were negative, and the patient was diagnosed with seronegative NMOSD with acute brainstem syndrome after meeting the diagnostic criteria. The patient’s condition improved after steroids administration.
CONCLUSIONS: We report an unusual presentation of seronegative NMOSD presenting with acute brainstem syndrome.

Keywords: Aquaporin 4, Brain Stem, dysphonia, Neuromyelitis Optica, Vomiting