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Myasthenia Gravis

Myasthenia Gravis: What You Need to Know about MG

  • Myasthenia gravis (MG) is a chronic autoimmune disorder in which antibodies destroy the communication between nerves and muscle, resulting in weakness of the skeletal muscles.

  • Myasthenia gravis affects the voluntary muscles of the body, especially those that control the eyes, mouth, throat and limbs.

  • The disease can strike anyone at any age, but is more frequently seen in young women (age 20 and 30) and men aged 50 and older.

  • A myasthenia gravis crisis can involve difficulty in swallowing or breathing.

  • The cause of myasthenia gravis is unknown and there is no cure, but early detection and prompt medical management can help people live longer, more functional lives.

What causes myasthenia gravis?

Myasthenia gravis is neither inherited nor contagious. The disorder generally develops spontaneously later in life as a result of a person’s own natural antibodies attacking normal receptors on muscle. This blocks the chemical released by the nerve endings (acetylcholine) from stimulating muscle contraction.

A temporary form of myasthenia gravis may develop in newborns when a woman with myasthenia gravis passes the antibodies to the fetus. Generally, neonatal myasthenia gravis resolves in 2 to 3 months.

Myasthenia Gravis Symptoms

The symptoms of myasthenia gravis may resemble those of other conditions, so always consult your doctor for a diagnosis. The following are the most common symptoms:

  • Visual problems, including drooping eyelids (ptosis) and double vision (diplopia). About two-thirds of people with myasthenia gravis experience eye issues as a first symptom.

  • Sudden, severe muscle weakness and fatigue in the neck or limbs may change in intensity over days or even hours and worsen as muscles are used.

  • Facial muscle involvement can cause a mask-like appearance; a smile may appear more like a grimace.

  • The person may have difficulty swallowing or pronouncing words.

Flare-ups and remissions (easing of symptoms) may occur periodically during the course of myasthenia gravis, but remissions are rarely permanent or complete.

Myasthenia Gravis Diagnosis

If you experience the onset of specific symptoms that point to myasthenia gravis, the doctor will ask about your medical history and symptoms and likely order some diagnostic tests.

One common way to diagnose myasthenia gravis is to test how a person responds to certain medications. Muscle weakness often dramatically improves for a brief time when a person with myasthenia gravis is given a type of medicine called an anticholinesterase. If a person responds to the medication, it confirms a diagnosis of myasthenia gravis.

Other diagnostic tests may include:

  • Blood tests: These tests look for antibodies that can show up in the blood of people with myasthenia gravis.

  • Genetic tests: These tests can see if your symptoms may be caused by a condition that has a tendency to run in families.

  • Electromyogram (EMG): An EMG measures the electrical activity of a muscle or a group of muscles and can detect abnormal electrical muscle activity due to diseases and neuromuscular conditions.

Myasthenia Gravis Treatment

Your doctor will determine your specific course of treatment based on:

  • Your age, overall health, and medical history

  • Extent of the condition

  • Your tolerance for specific medications, procedures, or therapies

  • Expectations for the course of the condition

  • Your opinion or preference

Myasthenia gravis is a lifelong medical condition and at present there is no cure. The key to medically managing it is early detection and a program of treatment to help control the symptoms.

Most people with this condition can improve their muscle strength and lead normal or near normal lives.

The goal of treatment is to increase muscle function and prevent swallowing and breathing problems. In more severe cases, respiratory or nutritional support may be needed.

Treatment may include:

  • Medications: Myasthenia gravis medications include anticholinesterase drugs, such as neostigmine bromide (Prostigmin®) or edrophonium (Tensilon®); steroids; or agents that suppress the immune system’s response.

  • Thymectomy: Surgical removal of the thymus gland reduces symptoms in more than 70% of people who do not have cancer of the thymus, possibly by altering the immune system response. The role of the thymus gland in myasthenia gravis is not fully understood.

  • Plasmapheresis: This procedure removes abnormal antibodies from the blood and replaces normal antibodies through donated blood.

  • Immunoglobulin: This is a blood product that helps to decrease the immune system’s attack on the nervous system; it is given intravenously (IV).

Myasthenia Gravis Crisis

Myasthenia crisis is a condition of extreme muscle weakness, particularly of the diaphragm and chest muscles that support breathing. Breathing may become shallow or ineffective.

In a severe crisis, weakened throat muscles and accumulation of saliva and mucus can obstruct the airway, and the individual may need to be placed on a ventilator to assist breathing until muscle strength returns with treatment.

Several factor can cause an MG crisis, including missing medication, a respiratory infection, emotional stress, surgery or some other type of stressor.

Certain steps can help prevent or minimize the occurrence of myasthenia crisis, including:

  • Taking anticholinesterase medications precisely as ordered by the doctor to help maintain the strength of the breathing muscles

  • Taking your medications 30 to 45 minutes before meals to reduce the risk of aspiration (food entering the lung passages)

  • Avoiding crowds and contact with people with respiratory infections, such as a cold or the flu

  • Getting proper nutrition to maintain optimal weight and muscle strength

  • Alternating periods of physical activity with periods of rest

  • Using stress-reduction techniques and avoiding emotional extremes

Avoid Myasthenia Gravis Medication Problems

It’s important for those with myasthenia gravis to inform all health care providers of your condition when they are prescribing medications. Certain medications may interfere either with the disease or the action of the drugs you take for myasthenia gravis.

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