Myasthenia gravis is caused by an abnormal immune reaction (antibody-mediated autoimmune response) in which the body's immune defenses (i.e., antibodies) inappropriately attack certain proteins in muscles that receive nerve impulses.
2. Definition:
Myasthenia gravis characterized by weakness
and rapid fatigue of muscles under your
voluntary control.
A neurological disorder in which antibodies
appears against Acetylcholine and Ach
receptor.
It is caused by break down in normal
communication between nerve and muscles.
6. Pathophysiology:
Your nerves communicate with your muscles by
releasing chemicals (neurotransmitters) that fit
precisely into receptor sites on the muscle cells
at the nerve-muscular junction.
In myasthenia gravis, your immune system
produces antibodies that block or destroy many
of your muscles' receptor sites for a
neurotransmitter called acetylcholine . With
fewer receptor sites available, your muscles
receive fewer nerve signals, resulting in
weaknes
7. Diagnostic Evaluation :
History and physical examination
Tensilon Test :- AntiCholinergic agent
(Edrophonium chloride) administer the one dose
via Intravenously 1.0 -2.0 mg (Adult) after
getting dose inhibits the breakdown of
acetylcholine making it available for it use at
neuromuscular junction and relief symptoms. A
positive test marks improvement in muscles
strength that last approx. 5 minutes..
Blood investigation
Electromyopathy
8. Management :
Medical management :
1. Anticholinergics –enhance communication between nerves and
muscles. These medications don't cure the underlying condition,
but they may improve muscle contraction and muscle strength.
E.g. Neostigmine , pyridostignine, Phystigmine
2. Corticosteroid – inhibit the immune system, limiting antibody
production e.g.Prednisone
3. Plasmapheresis - This procedure uses a filtering process similar
to dialysis. Your blood is routed through a machine that removes
the antibodies that block transmission of signals from your nerve
endings to your muscles' receptor sites. However, the beneficial
effects usually last only a few weeks.
9. Intravenous immunoglobulin – This therapy provides your
body with normal antibodies, which alters your immune
system response.
Surgical management :
Thymectomy : Thymoma tumor thymectomy may be
performed as an open surgery or as a minimally invasive
surgery. About 15 percent of the people with
myasthenia gravis have a tumor in their thymus gland,
10. Nursing management :
1. Assess patient for patent airway (muscles weakness of
diaphragms, respiratory and intercostal muscles).
2. Assess swallowing to prevent aspiration
3. Keep oxygen, endotracheal intubation and suction equipment,
bag valve mask available at bedside of patient
4. Provide small frequent high calories meals at times when
serum medicine level high.
5. Encourage patient to wear medication identification
wristband at all time.
11. 6 Position patient upright when eating and use more
thickners in liquids.
7. Use energy conservation measures allow for period of
rest.
8. Administer medication as prescribed.
9. Apply lubricating eye drop during the day and ointment at
night, if the client is unable to completely close the eye
apply tape to close eyes at night to prevent damage of
cornea.