Myasthenia Gravis
Myasthenia Gravis is an uncommon autoimmune neuromuscular
disease (directly affecting the nerves of the muscles)
that leads to muscle fatigue and weakness. It can
affect only one area, or be a generalized condition
affecting any muscles within the body.
According to the Myasthenia Gravis Foundation of
America Clinical Classification there are 5 classes
of Myasthenia Gravis.
• Class I: Any eye muscle weakness, possible
options, no other evidence of muscle weakness elsewhere
• Class II: Eye muscle weakness of any severity,
mild weakness of other muscle
•
Class IIa: Predominantly limb or axial muscles
•
Class IIb: Predominantly bulbar and/or respiratory
muscles
• Class III: Eye muscle weakness of any severity,
moderate weakness of other muscles
•
Class IIIa: Predominantly limb or axial muscles
•
Class IIIb: Predominantly bulbar and/or respiratory
muscles
• Class IV: Eye muscle weakness of any severity,
severe weakness of other muscle
•
Class IVa: Predominantly limb or axial muscles
•
Class IVb: Predominantly bulbar and/or respiratory
muscles (Can also include feeding tube without intubation)
• Class V: Intubation needed to maintain airway
Symptoms may wane and vary in severity and the initial
onset can be quite sudden. Initial signs and symptoms
may include fatigue, weakness in the muscles that
control the eye, facial expressions, chewing, breathing,
neck and limb movement.
Symptoms:
Difficulty chewing
Difficulty putting words in order
Difficulty speaking
Difficulty swallowing
Double vision
Droopy eyelids
Fatigue
Muscle fatigue after exercise
Shortness of breath
Weakness in eyelids
Weakness in the muscles of the eyes
Diagnosis:
Physical examination may show weakness and abnormalities
in the sensitivity and reflexes of the muscles. Imaging
such as CT Scans and MRI's may also be used to find
abnormalities in the muscle/nervous structures. Blood
tests may show:
Positive Anti-MuSK Protein Antibody
Positive Anti-Acetylcholine Recepter Antibody
Treatment:
There is no cure for Myasthenia Gravis, but treatment
options are available. Lifestyle adjustments such
as avoiding heat and stress can lessen the symptoms
and limiting activity and allowing rest periods can
help ease some of the muscle fatigue.
Some medications such as neostigmine or pyridostigmine
may help improve nerve communication while prednisone
and other immunosuppressant medications may be used
to control inflammation and reduce the immune response
causing the disorder.
For severe cases, plasma exchange may be considered
as an option to remove the antibodies causing the
abnormal immune responses. For patients experiencing
eye problems that drastically interfere with daily
living, there are surgical and non-surgical options
for correcting or improving vision problems.
Prognosis:
Overall, with treatment and lifestyle adjustments,
the prognosis is pretty good. Most patient can lead
normal or near-normal lives, with remissions being
possible. Very sever complications when respiration
is involved may require emergency care.
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