myasthenia gravis report

8/9/2019 Myasthenia Gravis Report

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SIENA COLLEGE TAYTAYCollege of Nursing

Researched by: Jillianne M. Bertiz SN

Myasthenia Gravis

What is myasthenia gravis?

Myasthenia gravis (MG) is a complex, autoimmune disorder in which antibodies destroy

neuromuscular connections. This causes problems with the nerves that communicate withmuscles. MG affects the voluntary muscles of the body, especially the eyes, mouth, throat, and

limbs.

Myasthenia gravis is a chronic autoimmune neuromuscular disease characterized by varying

degrees of weakness of the skeletal (voluntary) muscles of the body. The name myastheniagravis, which is Latin and Greek in origin, literally means grave muscle weakness. With

current therapies, however, most cases of myasthenia gravis are not as grave as the name

implies. In fact, for the majority of individuals with myasthenia gravis, life expectancy is not

lessened by the disorder.

What causes myasthenia gravis?

Myasthenia gravis may be inherited as a rare, genetic disease, it may be acquired by babies bornto mothers with MG, or the disorder may develop spontaneously later in childhood.

The hallmark of myasthenia gravis is muscle weakness that increases during periods of activity

and improves after periods of rest. Certain muscles such as those that control eye and eyelid

movement, facial expression, chewing, talking, and swallowing are often, but not always,involved in the disorder. The muscles that control breathing and neck and limb movements may

also be affected.

What causes myasthenia gravis?

Myasthenia gravis is caused by a defect in the transmission of nerve impulses to muscles. It

occurs when normal communication between the nerve and muscle is interrupted at the

neuromuscular junction the place where nerve cells connect with the muscles they control.Normally when impulses travel down the nerve, the nerve endings release a neurotransmitter

substance called acetylcholine. Acetylcholine travels through the neuromuscular junction and

binds to acetylcholine receptors which are activated and generate a muscle contraction.

In myasthenia gravis, antibodies block, alter, or destroy the receptors for acetylcholine at theneuromuscular junction which prevents the muscle contraction from occurring. These antibodies

are produced by the bodys own immune system. Thus, myasthenia gravis is an autoimmune

disease because the immune system which normally protects the body from foreign organisms mistakenly attacks itself.



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What is the role of the thymus gland in myasthenia gravis?

The thymus gland, which lies in the upper chest area beneath the breastbone, plays an important

role in the development of the immune system in early life. Its cells form a part of the bodys

normal immune system. The gland is somewhat large in infants, grows gradually until puberty,and then gets smaller and is replaced by fat with age. In adults with myasthenia gravis, the

thymus gland is abnormal. It contains certain clusters of immune cells indicative of lymphoid

hyperplasia a condition usually found only in the spleen and lymph nodes during an active

immune response. Some individuals with myasthenia gravis develop thymomas or tumors of thethymus gland. Generally thymomas are benign, but they can become malignant.

The relationship between the thymus gland and myasthenia gravis is not yet fully understood.

Scientists believe the thymus gland may give incorrect instructions to developing immune cells,ultimately resulting in autoimmunity and the production of the acetylcholine receptor antibodies,

thereby setting the stage for the attack on neuromuscular transmission.

What are the types of myasthenia gravis?

There are three types of MG in children, including the following:

congenital MG - this is a very rare non-immune form of MG that is inherited as an

autosomal recessive disease. This means that both males and females are equally affected

and that two copies of the gene, one inherited from each parent, are necessary to have thecondition. Symptoms of congenital MG usually begin in the baby's first year and are life-

long.

transient neonatal MG - between 10 and 15 percent of babies born to mothers with MG

may have a temporary form of MG. This occurs when antibodies common in MG crossthe placenta to the developing fetus. Neonatal MG usually lasts only a few weeks, and

babies are not at greater risk for developing MG later in life.

juvenile MG - this auto-immune disorder develops typically in female adolescents -especially Caucasian females. It is a life-long condition that may go in and out of

remission. About 10 percent of MG cases are juvenile-onset.

What are the symptoms of myasthenia gravis?

The following are the most common symptoms of myasthenia gravis. However, each child may

experience symptoms differently. Symptoms may include:

Babies with neonatal MG may be weak, with a poor suck, and may have respiratorydifficulty. A few babies may need the help of a mechanical breathing machine if their

respiratory muscles are too weak to breathe on their own. Symptoms go away as the

maternal antibodies disappear over time.

Congenital MG symptoms may begin in the first year, with generalized weakness in the

arms and legs, and delays in motor skills such as crawling, sitting, and walking. Babies

may have difficulty feeding and may have weak eyelids and poor head control.



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Juvenile MG symptoms may begin gradually over weeks or months. The child may

become excessively tired after very little activity, and begin to have problems chewing

and swallowing. Drooping eyelids may be so severe that the child cannot see.

The symptoms of myasthenia gravis may resemble other conditions. Always consult your child'sphysician for a diagnosis.

How is myasthenia gravis diagnosed?

The diagnosis of myasthenia gravis is made after the sudden or gradual onset of specific

symptoms and after diagnostic testing. During the physical examination, the physician obtains a

complete medical history of the child, and may also ask if there is a family history of anymedical problems.

Diagnosis of MG is usually confirmed with a Tensilon test. With this test, a small amount of

medicine (Tensilon) is injected into the child. If the child has MG, an immediate, but brief,increase in muscle tone is noted.

Other diagnostic tests that may be performed to help confirm the diagnosis of myasthenia gravis

include:

blood tests

genetic tests - diagnostic tests that evaluate for conditions that have a tendency to run infamilies.

electromyogram (EMG) - a test that measures the electrical activity of a muscle or a

group of muscles. An EMG can detect abnormal electrical muscle activity due to diseases

and neuromuscular conditions. muscle biopsy - a small sample of the muscle is removed and examined to determine and

confirm a diagnosis or condition.

Treatment of myasthenia gravis:

Specific treatment for myasthenia gravis will be determined by your child's physician based on:

your child's age, overall health, and medical history

the extent of the condition

your child's tolerance for specific medications, procedures, or therapies

expectations for the course of the condition your opinion or preference

There is no cure for MG, but the symptoms can sometimes be controlled. Myasthenia gravis is alife-long medical condition and the key to medically managing MG is early detection.

The goal of treatment is to prevent respiratory problems and provide adequate nutritional care to

the child since the swallowing and breathing muscles are affected by this condition.



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Treatment may include:

medications

thymectomy - surgical removal of the thymus gland. The role of the thymus gland in MG

is not fully understood, and the thymectomy may or may not improve a child's symptoms. plasmapheresis - a procedure that removes abnormal antibodies from the blood and

replaces the child's blood with normal antibodies through donated blood.

The extent of the problems is dependent on the severity of the condition and the presence ofother problems that could affect the child. In severe cases, a breathing machine may be required

to help the child breathe easier.

The healthcare team educates the family after hospitalization on how to best care for their child

at home and outlines specific clinical problems that require immediate medical attention by theirphysician. A child with MG requires frequent medical evaluations throughout his/her life.

It is important to allow the child as much independent function and self care, especially with

juvenile MG, as possible and to promote age-appropriate activities to ensure a sense of normalcy.


myasthenia gravis report

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