Beyond Classics: Area Postrema Syndrome as a Rare Presentation of Neuromyelitis Optica Spectrum Disorder

Background: Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathic disease of the central nervous system. It typically involves the optic nerves, spinal cord, and brainstem, but can also manifest atypically. Area postrema syndrome (APS), a recognized core clinical manifestation of NMOSD, is characterized by intractable nausea, vomiting, or hiccups. When APS presents in isolation, diagnosis can be challenging, as symptoms are frequently attributed to gastrointestinal disorders, leading to delays in appropriate management. Recognition relies on characteristic neuroimaging findings and the detection of serum aquaporin-4 immunoglobulin G (AQP4-IgG), after the exclusion of alternative causes. Case Report: The reported case highlights area postrema syndrome as an uncommon initial presentation of neuromyelitis optica spectrum disorder in a 33-year-old female. The patient presented with intractable nausea and vomiting, which initially led to extensive investigations of gastrointestinal etiologies. The subsequent development of neurological symptoms, including nystagmus, ataxia and a characteristic lesion in the dorsal medulla on magnetic resonance imaging (MRI), ultimately led to the diagnosis of NMOSD. This case, underscores the importance of considering NMOSD in patients presenting with otherwise unexplained APS, even in the absence of typical findings such as optic neuritis or transverse myelitis. Although cerebrospinal fluid (CSF) analysis was normal and the initial CSF test for Aquaporin-4-IgG (AQP4-IgG) was negative, a subsequent blood test for the same antibody returned positive. This confirmed the diagnosis of Neuromyelitis Optica Spectrum Disorder (NMOSD). Immediate treatment with intravenous methylprednisolone led to significant clinical improvement. At the one-month follow-up, she was symptom-free and ambulating independently. Conclusion: Physicians in developing countries need to be more aware of the rare disease NMOSD. This case shows that a high level of suspicion is crucial for a quick diagnosis and to prevent treatment delays.