Signs and Symptoms of Myasthenia Gravis

Initial symptoms of MG may include

  • difficulty speaking (dysarthria),
  • difficulty swallowing (dysphagia),
  • drooping eyelids (ptosis), and
  • double vision (diplopia).

Patients often have nasal-sounding speech and weak neck muscles that give the head a tendency to fall forward or backward. These symptoms occur in about 90 percent of MG cases, are usually intermittent (i.e., come and go), and may disappear for weeks and then recur.

Generalized weakness often develops in the trunk, arms, and legs within a year of onset. Arm muscles usually are affected most severely. Muscle weakness tends to worsen as the day progresses, especially after prolonged activity.

Pregnancy can improve, worsen, or have little effect on MG symptoms. Frequently, symptoms first occur during pregnancy or after delivery.

Myasthenia Gravis Complications

Myasthenic crisis is a medical emergency that develops when muscles that control breathing become severely weakened. This condition may lead to acute respiratory failure and patients often require a respirator to assist breathing during the crisis. Other complications that may develop include choking, food aspiration, and pneumonia.

Factors that can trigger complications in patients with myasthenia gravis include illness (e.g., viral respiratory infection), surgery, corticosteroid use that is tapered too quickly, overexertion (especially in hot weather), pregnancy, and emotional stress.

Publication Review By: Stanley J. Swierzewski, III, M.D.

Published: 31 Dec 1999

Last Modified: 25 Sep 2015