Myasthenia Gravis: Symptoms, Diagnosis and Treatment

MYASTHENIA GRAVIS

Myasthenia Gravis is a painful and long-term disorder of the nervous system affecting muscles. In this there is a periodical fatiguability of the muscles. The voluntary muscles get tired with abnormally quick speed. The muscles associated with the skeletal system like eyes, mouth, tongue, limbs are affected in this disease. The defect is found in the transmission of the impulses from the rerves to the muscles though the nerves and the muscles themselves are found to be absolutely faultless.

This disease characteristically starts before the age of 40 years in females and above the age of 40 years in males, and it is less common among children. This disease is neither contagious nor hereditary.

From a doctor’s point of view this disease is divided into 4 stages and one of the primary symptoms of this disease is weakness of the eye muscles. In some patients this disease is limited to the eyes only, but in majority of cases after some time other muscles which control the functions like laughing, chewing, swallowing, speaking and the movement of limbs are affected and ultimately the muscles controlling the respiration function are also affected and the life of the patient is endangered.

Main Symptoms :

·           Drooping of one or both eyelids.

·           Imbalance, weakness and lethargy in walking.

·           Weakness in hands as well as fingers.Difficulty in swallowing food.

·           Difficulty in talking, lowering of voice while talking, sounds from the nose.

·           Problems of respiration.

Respiratory problems in a patient suffering from Myasthenia Gravis can prove fatal. It is very important to admit such a patient to the hospital. In the advanced stage of the disease or in stressful physical situations like infection or pregnancy, respiratory problems can occur.

There is a recurring weakness in the muscles due to this disease, which may subside or increase in a period of time or remain as it is for a long time. Though the intensity of this disease can vary every hour in a patient and from patient to patient, at the end of the day the patient may seem weaker due to exertion and slight improvement may be seen after relaxing. In these circumstances, the patient can lead a near normal life with the help of modern treatment.

In this disease the thymus gland also plays a very important role. The cells of this gland are considered a part of the immune system of the body. This gland situated in the chest, is large in infancy, which gradually reduces in size with age, and in an adult it is almost invisible. But in most of the patients of Myasthenia Gravis, the thymus gland is found to be large. In 10% to 15% patients a tumor of the thymus gland called thymoma is seen which is usually benign, but sometimes there may be a possibility of malignancy. S % of these patients are also seen to be suffering from associated thyroid disorders.Myasthenia Gravis can crop up suddenly and cause aggressive weakness in all the muscles. Many a time it is difficult to diagnose the disease from the primary symptoms, but a specialist doctor can detect the disease from its signs and symptoms. Special attention is given to the fatiguability of the ocular muscles and the muscles of the limbs.

Diagnosis :

1.        Acetylcholine receptor antibody test.

2.        E.M.G: The nerves are stimulated electrically, whichcan demonstrate the defect in their capability to conduct the impulses.

3.        Tilstigmintest :If an injection of tilstigmin givesimmediate relief in the symptoms, it is considered as the confirmation of the diagnosis.

4.        CT Scan thorax :this test is mainly done to detectthe tumor called thymoma in the chest.

5.        Thyroid function tests and other relevant blood tests.

Treatment :

Anticholinesterase drugs like neostigmine or pyridostigmine are used in the treatment of this disease that strengthens the impulse going from the nerves to the muscles. This helps in the availability of acetylcholine for a longer period, increasing the contractibility of the muscles. This medicine is very beneficial for the patient but it does not help the patient to carry on all his activities with the strength he had before the onset of the disease.

The surgical removal of thymus gland proves to be more effective. More than 50% of the patients benefit if this surgery is done in the initial stage of the disease. Rest ofthe patients benefit by the use of the steroid group of drugs. Some patients get relief by a drug called Azathioprine, but its long-term use causes side effects.

In severely afflicted patients, a treatment called Plasmapheresis is done, in which the patients own blood is transfused back after purifying it. This process removes the acetylecholine antibodies and other toxins, which cause the defect in the conduction of the impulse to the muscles. This treatment is attempted when all other treatments have failed and the patient is in serious condition. This treatment can save life of the patient in myasthenic crisis or when the disease reaches the third, fourth or last stage.

Another treatment which is as effective as Plasmapheresis but extremely expensive is the Immunoglobulin therapy, in which immunoglobulin collected from the blood of healthy individuals or prepared synthetically is introduced in the patients body in very high doses. Usually a dose of 400-mgm\lcg-body weight is given per day for 3-5 days The approximate expenditure of this treatment is about 1.5 lakh Indian Rupees (15C1 Thousands). This treatment can rapidly control the disease and the patient’s life can be saved.

Myasthenia gravis is a difficult and tough disease. The intensity as well as the frequency of the disease being different in every patient. If diagnosis is done in the early stages and treatment taken from a specialist most of the patients get relief and lives can be saved. Only a specialist can decide which drug or therapy is most suitable for a particular patient.