Chronic inflammatory demyelinating polyradiculoneuropathy associated with neuromyelitis optica spectrum disorder: A rare case report.

Introduction: Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a rare disease that targets the myelin sheath, while neuromyelitis optica spectrum disorder (NMOSD) with anti-aquaporin-4 antibodies (AQP4-Ab) affects astrocytes. We report a unique case of CIDP associated with NMOSD. Case presentation: A 49-year-old woman presented to the emergency department with recurrent episodes of vertigo and blurred vision. Brain magnetic resonance imaging (MRI) with contrast eight months before admission showed Dawson's finger, and follow-up brain MRI showed a new hyperintense lesion. Visual evoked potential showed bilateral pre-chiasma lesions, and somatosensory evoked potential indicated lesions between the medulla and cerebral cortex. The patient tested positive for AQP4-Ab, and had ascending lower motor neuron weakness for the past 10 weeks. Electromyography revealed multiple demyelinating lesions suggestive of CIDP. The patient was intravenously administered corticosteroids, methotrexate, and azathioprine, resulting in clinical improvement. Conclusion: CIDP associated with NMOSD is a rare occurrence. In our patient, a combination of corticosteroids and immunosuppressants was effective. The mechanism of combined demyelination of the central and peripheral nervous systems is still not fully understood, and further immunological and pathological studies are needed.