Identifying risk factors for rapid progression of multiple sclerosis and initiating effective treatment are crucial for preventing disability, particularly in patients with relapsing remitting disease who develop a severe, rapidly progressive form. A 21 year old man presented with progressive lower limb weakness and gait disturbance, preceded by transient symptoms. Physical examination revealed pyramidal weakness, sensory impairment, and dysmetria (Expanded Disability Status Scale, EDSS 6.0). Magnetic resonance imaging showed more than 20 contrast enhancing T2/FLAIR lesions located cortically, periventricularly, in the corpus callosum, infratentorially, and within the spinal cord. Oligoclonal bands were present in cerebrospinal fluid. Steroid therapy led to improvement, but a relapse occurred one week later (EDSS 4.0), accompanied by new magnetic resonance imaging lesions. After initiation of natalizumab, remission was achieved at 12 months (EDSS 2.0). Risk factors for rapid progression include male sex, high early disease activity, motor or cerebellar symptoms, and extensive spinal cord involvement. Early recognition of a severe, rapidly progressive form of multiple sclerosis and timely initiation of high efficacy disease modifying therapy are essential to prevent disability.

multiple sclerosis, relapsing remitting multiple sclerosis, rapidly evolving severe multiple sclerosis, aggressive multiple sclerosis