Myasthenia gravis

• A
• B
• C
• D
• E
• F
• G
• H
• I
• J
• K
• L
• M
• N
• O
• P
• Q
• R
• S
• T
• U
• V
• W
• X
• Y
• Z

Superficial anterior muscles

• Vision changes:
  • Double vision
  • Difficulty maintaining steady gaze
  • Eyelid drooping
• Patients with generalized disease may also have:
  • Swallowing difficulty, frequent gagging or choking
  • Weakness or paralysis (may worsen with exertion later in the day)
  • Muscles that function best after rest
  • Drooping head
  • Difficulty climbing stairs
  • Difficulty lifting objects
  • Need to use hands to rise from sitting positions
  • Difficulty talking
  • Difficulty chewing

• Hoarseness or changing voice
• Fatigue
• Facial paralysis
• Drooling
• Breathing difficulty

Examination may be normal or may show muscle weakness that progressively worsens as the muscle is used. In many patients the eye muscles are affected first. Reflexes and sensation are normal. Weakness may affect the arms, legs, breathing or swallowing muscles and any other muscle group.

• Standard EMG results are usually normal.
• Repetitive stimulation (type of nerve conduction study) is more sensitive.
• Single-fiber EMG is even more sensitive.
• Acetylcholine receptor antibodies may be present in the blood.
• A Tensilon test is positive in some cases but must be interpreted carefully by an experienced doctor. Baseline muscle strength is evaluated. After Tensilon (edrophonium, a medication that blocks the action of the enzyme that breaks down the transmitter acetylcholine) is given, muscle function may improve.

Review Date: 08/07/2006
Reviewed By: Daniel Kantor, M.D., Director of the Comprehensive MS Center, Neuroscience Institute, University of Florida Health Science Center, Jacksonville, FL. Review provided by VeriMed Healthcare Network.