Multiple Sclerosis and Myasthenia Gravis

Multiple sclerosis (MS) and myasthenia gravis (MG) can both produce weakness, visual complaints, impaired mobility, and fatigue, but the problem occurs in different parts of the nervous system. MS is an inflammatory demyelinating disease of the central nervous system. Damage to myelin slows or blocks conduction in the brain, optic nerves, and spinal cord. Findings are therefore often separated by anatomical location and time: optic neuritis, sensory loss, limb weakness, ataxia, spasticity, bladder dysfunction, or cognitive change may appear in different combinations. The classic Charcot triad—nystagmus, intention tremor, and scanning speech—is a useful recognition pattern, not a diagnostic requirement. MG is a disorder of neuromuscular transmission. Autoantibodies impair signalling at the neuromuscular junction, so the muscle can initially contract but becomes less able to respond with repeated use. Weakness fluctuates. Extraocular and bulbar muscles are commonly affected: ptosis, diplopia, dysarthria, dysphagia, and a nasal or fading voice may precede generalized weakness. Sensation remains intact, and cognition is not altered by MG itself. A patient with MS may report a persistent new area of numbness, visual loss, or imbalance. A patient...