The primary pathological event in multiple sclerosis (MS) lesion development is an immune-mediated destruction of the neuronal myelin sheath. The inflammatory lesions of MS can affect any part of the central nervous system and optic nerves, resulting in a wide variety of presenting symptoms. The first symptoms of MS are commonly weakness, paresthesias, visual loss, incoordination, vertigo, and sphincter impairment. Focused testing of cranial nerve function, strength, coordination, gait, and sensation, and an evaluation for pathological reflexes are important. The onset of MS is heralded by a bout of optic neuritis in about 20% of patients with MS, and more than 50% of patients with optic neuritis eventually develop the disease. Neuroimaging assists in differentiating MS from mass lesions, infections, or strokes. Patients with relapsing-remitting multiple sclerosis (RRMS) who experience an acute exacerbation of their illness present with either recurrence or worsening of old symptoms, or entirely new neurological symptoms.