200 Section - Neuromyelitis Optica Initially Misdiagnosed as Multiple Sclerosis: A Rare Case of Isolated Dysphagia

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune demyelinating disease of the central nervous system that primarily affects the optic nerves and spinal cord. Its clinical presentation often overlaps with multiple sclerosis (MS). We report a unique case of NMOSD initially presenting with progressive dysphagia, which improved with immunotherapy and rehabilitation.

Case Description:

A 53-year-old woman was diagnosed with MS in 2009 based on cervical spine MRI showing signal changes and brain MRI revealing lesions in the midbrain and hypothalamus. Symptoms were improved with steroids. In 2012 she developed ptosis and diplopia and NMOSD was suspected. So Rebif (Interferone β-1a) was discontinued, and steroid treatment led to improvement. NMO antibody was negative in 2012 but turned to positive on anti-Aquaporin 4 in 2022.

In April 2025, she presented with severe dysphagia and generalized weakness. Brain MRI showed new T2 hyperintense lesions with diffusion restriction in the right lateral medulla, pons, and left periventricular white matter.  Videofluoroscopic swallowing study (VFSS) showed delayed pharyngeal swallowing reflex, reduced laryngeal motion, and cricopharyngeal dysfuction (CPD) grade 4 with aspiration.

After rehabilitation, VFSS showed better peristalsis and laryngeal motion, with CPD downgraded to grade 2.  No aspiration was seen with semisolids but aspiration with liquids.

Discussions:

This case highlights the potential for NMOSD to be misdiagnosed as MS due to overlapping features such as optic neuritis, longitudinally extensive myelitis, and nonspecific white matter lesions. Both disorder may show a relapsing–remitting course and similar MRI findings, complicating early differentiation. Serologic tests may also be inconclusive—AQP4-IgG can initially test negative in NMOSD, and oligoclonal bands are not always present in MS

Conclusions: NMOSD should be considered in the differential diagnosis of progressive dysphagia with brainstem lesions. Timely diagnosis, appropriate immunotherapy, and early rehabilitative intervention are essential for achieving meaningful functional recovery in patients with severe bulbar symptoms