|
|
What is Myasthenia Gravis? |
| | | | |
Symptoms
Myasthenia gravis is a disorder which is identified with feebleness and fatigue of any of the body’s voluntary muscles. The disease only interferes with muscle functioning though, and the feebleness is recovered with rest. It can afflict all ages, but women below forty and above seventy are highly susceptible to it, as well as men above the age of fifty. Usual symptoms include feebleness of the facial muscles, droopy eyelids, or a difficulty in swallowing, breathing, and chewing; doubled vision, limb weakness, and a tendency to tire easily with repeated body movements. The fatigue worsens with increased repetition of movements, although there are days when the patient will feel relatively well. The condition may also improve at times, but these periods are brief and seldom happen.
Causes
A natural chemical called acetylcholine is responsible for the efficient transmission of impulses to the muscles, and in myasthenia gravis, a functional impairment occurs which interferes with this communication. For still unknown causes, the condition encourages the immune system to manufacture antibodies which either obstruct or destroy the muscles’ impulse receptors. With fewer of these functioning, the received impulses become insufficient, resulting in debilitation. The thymus gland is partly responsible for triggering or regulating the creation of these antibodies. The gland is normally smaller for healthy adults, but patients with myasthenia gravis have an unusually large thymus; some may also bear non-malignant tumors on the gland. There are factors which can worsen the condition, including, stress, severe heat, and medicines like beta blockers, quinine, and certain types of antibiotics.
Diagnosis
The main indicator for the condition is muscle debilitation which subsides with rest. A neurological exam may be conducted to confirm the suspicion, wherein the patient’s tactile, mental, and visual capabilities are evaluated along with his muscle reflex, vigor, tone, and coordination. Blood tests may also detect the existence of abnormal antibodies which impair the sites that receive the electric signals for muscle movement, or an intravenous shot of edrophonium may indicate myasthenia gravis with an abrupt, yet brief improvement with muscle activity. Finally, a two-part test may be conducted to evaluated the efficiency of muscle contractions (nerve conduction), and to measure the impulse during intervals of rest and slight contractions (single-fiber electromyography).
Treatment Info
The treatment possibilities for myasthenia gravis may be employed as stand-alone procedures, or they may be used in combination. There are several medications which can affect the way the impulses are transmitted between the nerves and the muscles; for instance, a cholinesterase inhibitor like neostigmine and pyridostigmine enhances their communication. While these do not actually treat the cause of the condition, they help improve the muscle’s endurance and the efficiency of its contractions. For similar purposes, corticosteroids, azathioprine, or cyclophosphamide may also be taken either to hamper or induce changes in the immune system. Surgery is another treatment option, wherein the thymus gland is removed to provide long-lasting relief from the condition. If the latter proves to be life-threatening, the abnormal antibodies may be extracted through plasmapheresis, and consequently replaced with healthy antibodies through the intravenous introduction of immune globulin.
| | | |
| |
|
| |
|
|
| |
|
