This 44-year-old woman had a history of neurologic symptoms dating back to her early teenage years. In her early 20s, she had an acute onset of vertigo, lower extremity weakness, and fatigue followed by progressive balance difficulties and urinary incontinence.

Our patient had intermittent symptoms, most notably fatigue, dizziness, leg weakness, poor balance, urinary impairment, and ocular dismotility for several years. Examination was notable for bilateral INO and a spastic and ataxic gait. She was diagnosed with multiple sclerosis (MS).

MS is a chronic demyelinating disease of the central nervous system (CNS) resulting in injury to the myelin sheaths, oligodendrocytes, and eventually axons. The clinical diagnosis of MS requires two temporally dissociated attacks of demyelination referable to two anatomically separate white matter pathways of the brain or spinal cord. Such definition can be met at the initial clinical event if magnetic resonance imaging (MRI) lesions are sufficient proof for dissemination in space and time, according to the McDonald criteria (2001). The clinical profile of MS can be classified as relapsing-remitting (RRMS 85%), progressive relapsing (PRMS),
secondary progressive (SPMS), and primary progressive (PPMS). Most common symptoms at onset of MS are visual, oculomotor dysmotility, sensory disturbances, or incoordination. Approximately 20% of patients with MS present with optic neuritis (ON) as the first demyelinating event. Traditionally, MS has been diagnosed on the basis of clinical findings and supporting evidence from ancillary investigations such as MRI of the brain, and cerebrospinal fluid (CSF) analysis. However, CSF is no longer routine in the investigation of MS, although it remains useful when MRI is either nondiagnostic or not available.