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Elsabet H. Tekle, DDS LLC
- A Caring Dentist
Dr. Tekle and
staff focus on the total elimination of pain through the use of nitrous
oxide analgesia and painless injection techniques. We provide
conservative white fillings, smile makeover, teeth whitening, implants,
treatment for dysfunctional TMJ and gum disease. |
The voluntary muscles of the entire body are controlled by
nerve impulses that arise in the brain. These nerve impulses travel down
the nerves to the place where the nerves meet the muscle fibers. Nerve
fibers do not actually connect with muscle fibers. There is a space
between the nerve ending and muscle fiber; this space is called the
neuromuscular junction.
When the nerve impulse originating in the brain arrives at the nerve
ending, it releases a chemical called acetylcholine. Acetylcholine
travels across the space to the muscle fiber side of the neuromuscular
junction where it attaches to many receptor sites. The muscle contracts
when enough of the receptor sites have been activated by the
acetylcholine. In MG, there is as much as an 80% reduction in the number
of these receptor sites. The reduction in the number of receptor sites
is caused by an antibody that destroys or blocks the receptor site.
Antibodies are proteins that play an important role in the immune
system. They are normally directed at foreign proteins called antigens
that attack the body. Such foreign proteins include bacteria and
viruses. Antibodies help the body to protect itself from these foreign
proteins. For reasons not well understood, the immune system of the
person with MG makes antibodies against the receptor sites of the
neuromuscular junction. Abnormal antibodies can be measured in the blood
of many people with MG. The antibodies destroy the receptor sites more
rapidly than the body can replace them. Muscle weakness occurs when
acetylcholine cannot activate enough receptor sites at the neuromuscular
junction.
Common symptoms can include:
- A drooping eyelid
- Blurred or double vision
- Slurred speech
- Difficulty chewing and swallowing
- Weakness in the arms and legs
- Chronic muscle fatigue
- Difficulty breathing
Treatments for Myasthenia Gravis (MG)
There is no known cure for MG, but there are effective treatments that
allow many-but not all-people with MG to lead full lives. Common
treatments include medications, thymectomy and plasmapheresis.
Spontaneous improvement and even remission may occur without specific
therapy.
Medications are most frequently used in treatment. Anticholinesterase
agents (e.g., Mestinon®) allow acetylcholine to remain at the
neuromuscular junction longer than usual so that more receptor sites can
be activated. Corticosteroids (e.g., prednisone) and immunosuppressant
agents (e.g., Imuran®) may be used to suppress the abnormal action of
the immune system that occurs in MG. Intravenous immunoglobulins (IVIg)
are sometimes used to affect the function or production of the abnormal
antibodies also.
Thymectomy (surgical removal of the thymus gland) is another treatment
used in some patients. The thymus gland lies behind the breastbone and
is an important part of the immune system. When there is a tumor of the
thymus gland (in 10-15% of patients with MG), it is always removed
because of the risk of malignancy. Thymectomy frequently lessens the
severity of the MG weakness after some months. In some people, the
weakness may completely disappear. This is called a remission. The
degree to which the thymectomy helps varies with each patient.
Plasmapheresis, or plasma exchange, may be useful in the treatment of MG
also. This procedure removes the abnormal antibodies from the plasma of
the blood. The improvement in muscle strength may be striking, but is
usually short-lived, since production of the abnormal antibodies
continues. When plasmapheresis is used, it may require repeated
exchanges. Plasma exchange may be especially useful during severe MG
weakness or prior to surgery.
Treatment decisions are based on knowledge of the natural history of MG
in each patient and the predicted response to a specific form of
therapy. Treatment goals are individualized according to the severity of
the MG weakness, the patient's age and sex, and the degree of
impairment.
What is the prognosis for those with MG?
The current treatments for MG are sufficiently effective that the
outlook for most patients is bright. Although the treatments will not
cure MG, most patients will have significant improvement in their muscle
weakness. In some cases, MG may go into remission for a time, during
which no treatment is necessary. There is much that can be done, but
still much to understand. New drugs to improve treatments are needed.
Research plays an important role in finding new answers and treatments
for MG. |
