Weakness and Fatigue
MG weakens and fatigues the body’s voluntary muscles (those we can move at will). It doesn’t damage the musculature of the heart or the gastrointestinal tract.
Early in its course, MG tends to affect the muscles that control movement of the eyes and eyelids, causing ocular weakness. Consequently, a partial paralysis of eye movements (ophthalmoparesis), double vision (diplopia), and droopy eyelids (ptosis) are usually among the first symptoms of MG.
Weakness and fatigue in the neck and jaw also can occur early in MG. This bulbar weakness — named for the nerves that originate from the bulblike part of the brainstem — can make it difficult to talk, chew, swallow and hold up the head. Bulbar weakness tends to give speech a slurred, nasal quality. It can also lead to frequent choking spells, and make eating unpleasant and tiresome.
In generalized MG, weakness tends to spread sequentially from the face and neck to the upper limbs, the hands and then the lower limbs. It may become difficult to lift the arms over the head, rise from a sitting position, walk long distances, climb stairs or grip heavy objects.
In severe cases, weakness may spread to muscles in the chest that control breathing.
