Myasthenia gravis is a chronic autoimmune neuromuscular disease in which the immune system attacks healthy skeletal muscles by mistake. It is characterised by muscle weakness that increases during periods of activity and improves after periods of rest.

Myasthenia gravis causes muscle weakness by affecting the strength and control of the muscles, especially facial muscles such as eye and eyelid movement, facial expressions and swallowing. The muscles that control breathing and neck and limb movements may also be affected.

Causes

Myasthenia gravis occurs when normal communication between the nerve and the muscle is interrupted, leaving the muscle weak and fatigued. There is no known cause for this happening.

Symptoms

Symptoms are often misdiagnosed at first due to the fact that weakness is a common symptom associated with many other problems, especially if symptoms are mild or only a few muscles affected. In most cases, the first noticeable symptom is weakness of the eye muscles. The degree of muscle weakness involved in myasthenia gravis varies greatly among individuals.

Different muscles can be affected to different degrees. The following symptoms may occur:

    • Breathing difficulty or shortness of breath
    • Chewing or swallowing difficulty
    • Difficulty talking
    • Drooping head
    • Weakness of the facial muscles
    • Fatigue
    • Hoarseness or changing voice
    • Blurred or double vision or difficulty maintaining a steady gaze
    • Eyelid drooping
    • Unstable when walking
    • Weakness in the arms, hands, fingers, legs and neck.

 

Minor changes or adaptations to one’s lifestyle may help in easing the effects. These could include:

    • Having rest periods during the day
    • Wearing an eye patch to minimise double vision
    • Avoiding stress
    • Avoiding heat exposure.

Who is affected?

Anyone can be affected, but myasthenia gravis occurs most commonly in women under 40 and men over 60. Myasthenia gravis is not directly inherited and is not contagious.

Treatments

There is no known cure for myasthenia gravis. However, there are several treatments available to decrease and improve symptoms, and may even allow sufferers to have extended periods without experiencing any symptoms. In some cases, muscle weakness may improve significantly and permanently so that treatment can be stopped. With current therapies people suffering from myasthenia gravis generally have a normal life expectancy.

 

Sources
www.myasthenia.org.au
www.ncbi.nlm.nih.gov
www.ninds.nih.gov