Autoimmune, with contribution from genetic and environmental factors
Causes inflammation, demyelnation and inury to affected areas
Risk Factors
White>black
Women>men
Age onset typically <40
Symptoms
Sub-acute
Waxes/wanes
Fatigue
Affects spinal cord and brain, in a patchy fashion; presentations are highly variable
Progresses over year/decades
Patchy sensory and motor deficits that can affect any of the neuro pathways and don't follow an anatomic pattern
Most common presentations include: optic neuritics (variable degrees of visual loss, 90% one eye, pain with eye movement, double vision, impaired color vision); myelitis (cord: partial sensory or motor symptoms below affected level, shock-like sensation traveling down spine or limbs provoked by neck movement, urinary retention or frequency), brainstem (eye movement problems causing diplopia, sensation jerking visual fields) and cerebellar lesions (imbalance, dizziness/vertigo)
Often symptoms occur intermitently, with flares/relapses for days to weeks or months, and then may improve
Symptoms can relapse and remit (85% of cases) w/episodic flairs and then recovery (to some degree); primary progressive (later age onset, progression w/o remission); secondary progressive
Often worsened with elevations in temperature (e.g. infection)
Sometimes band like sensation around abdomen or chest
Sometimes cognitive dysfunction
Physical Exam Findings
Objective findings that document CNS based dysfunction
Can be sensory, motor, optic, cerbellar, brain stem or cranial nerves
Eye findings can include: decline in acuity (usually one eye), visual field deficits, afferent pupillary defect, impaired extraoccular movement, impaired color vision, optic nerve edema
Motor: focal weakness; doesnt usually affect whole cord, so findings are patchy; affected muscles initially flacid and then spasticity if dont recover
Sensory: Decreased sensation, affecting same distribution as motor findings; doesnt usually affect whole cord, so decreased sensation is patchy
Cerbebellar: ataxia, impaired fine motor (e.g. finger to nose)