Final answer:
Myasthenia gravis is an autoimmune disorder that causes muscle weakness, starting with drooping eyelids and expanding to include overall muscle weakness and fatigue. The disease progresses to muscles elsewhere in the body, affecting swallowing, chewing, and speech. Emergency medical care may be required for breathing issues during myasthenia crises.
Step-by-step explanation:
Myasthenia gravis is an autoimmune disorder in which circulating antibodies block the nicotinic acetylcholine receptors on the neuromuscular junction's motor endplate. This blockage of acetylcholine receptors causes muscle weakness, often first exhibiting drooping eyelids and expanding to include overall muscle weakness and fatigue. The initial symptom of myasthenia gravis is painless muscle weakness, generally in muscles around the eye (Figure 15.6.5). The disease then progresses to muscles elsewhere in the body, eventually involving most of the muscles. Swallowing and chewing may become difficult as the disease progresses, and speech may become slow and slur. In more advanced cases, myasthenia crises may occur, during which the muscles that control breathing may be affected. Emergency medical care to provide assisted ventilation is required to sustain life. A myasthenia gravis crisis may be triggered by various stressors, such as infection, fever, or stress. Treatment of myasthenia gravis may include medications to counter the mutant gene's effects or suppress the immune system.