Symptoms:

Myasthenia gravis causes weakness of the voluntary (skeletal) muscles. Voluntary muscles are those that are under your control. In other words, you think about moving your arm, and it moves. The muscle weakness of myasthenia gravis worsens with activity and improves with rest.

The muscle weakness can lead to a variety of symptoms, including:

• Breathing difficulty because of weakness of the chest wall muscles
• Chewing or swallowing difficulty, causing frequent gagging, choking, or drooling
• Difficulty climbing stairs, lifting objects, or rising from a seated position
• Difficulty talking
• Drooping head
• Facial paralysis or weakness of the facial muscles
• Fatigue
• Hoarseness or changing voice
• Double vision
• Difficulty maintaining steady gaze
• Eyelid drooping

Signs and tests:

The health care provider performs a physical exam, including a detailed nervous system (neurological) examination. This may show:

• Muscle weakness - eye muscles are usually affected first
• Reflexes and feeling (sensation) are normal.

Tests that may be done may include:

• Acetylcholine receptor antibodies associated with this disease
• CT or MRI scan of the chest to look for a tumor
• Nerve conduction studies
• EMG