Atypical Neuromyelitis Optica Spectrum Disorder: A Case of Unilateral Optic Neuritis and Partial Transverse Myelitis.

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune disease characterized by inflammation of the optic nerves and spinal cord, leading to optic neuritis and transverse myelitis. Atypical cases of NMOSD pose diagnostic challenges, particularly when initial symptoms deviate from classical presentations. We report an atypical NMOSD case involving a 22-year-old female presenting with unilateral optic neuritis and incomplete transverse myelitis. The patient exhibited myoclonus, acute urinary retention, and autonomic dysfunction. Diagnosis was confirmed through clinical assessment, ophthalmological evaluation, cerebrospinal fluid analysis, magnetic resonance imaging (MRI), and aquaporin-4 antibody testing. The patient responded positively to intravenous immunoglobulin and high-dose methylprednisolone, followed by maintenance azathioprine (rituximab planned as escalation if needed). This case underscores the crucial importance of early identification and timely serological testing in atypical presentations of NMOSD, particularly in resource-constrained settings.