Some people with myasthenia gravis have a tumor in the thymus gland, a gland under the breastbone that is involved with the immune system.
Medications and blood-filtering therapies help people to again breathe on their own. Emergency treatment and mechanical assistance with breathing are needed. Myasthenic crisis is a life-threatening condition that occurs when the muscles that control breathing become too weak to work. Some medications - such as beta blockers, quinidine gluconate, quinidine sulfate, quinine (Qualaquin), phenytoin, certain anesthetics and some antibioticsĬomplications of myasthenia gravis are treatable, but some can be life-threatening.Factors that can worsen myasthenia gravis Some children are born with a rare, hereditary form of myasthenia gravis, called congenital myasthenic syndrome. If treated promptly, children generally recover within two months after birth.
Rarely, mothers with myasthenia gravis have children who are born with myasthenia gravis (neonatal myasthenia gravis). Usually, thymomas aren't cancerous (malignant), but they can become cancerous. Some people with myasthenia gravis also have tumors of the thymus gland (thymomas). In some adults with myasthenia gravis, however, the thymus gland is abnormally large. Large in infancy, the thymus gland is small in healthy adults. Researchers believe that the thymus gland triggers or maintains the production of the antibodies that block acetylcholine. The thymus gland is a part of your immune system situated in the upper chest beneath your breastbone. The thymus gland, a part of your immune system situated in the upper chest beneath the breastbone, may trigger or maintain the production of antibodies that result in the muscle weakness. In general, researchers assume that these types of myasthenia gravis still have an autoimmune basis but the antibodies involved are just not detectable yet. This type of myasthenia gravis is called seronegative myasthenia gravis or antibody-negative myasthenia gravis. Some people have myasthenia gravis that isn't caused by antibodies blocking acetylcholine, MuSK or LRP4. Other antibodies have been reported in research studies and the number of antibodies involved will likely expand over time. Antibodies against another protein, called lipoprotein-related protein 4 (LRP4), can play a part in the development of this condition. Antibodies against this protein can lead to myasthenia gravis. This protein is involved in forming the nerve-muscle junction. With fewer receptor sites available, your muscles receive fewer nerve signals, resulting in weakness.Īntibodies can also block the function of a protein called muscle-specific receptor tyrosine kinase (TIE-roh-seen KIE-nays), sometimes referred to as MuSK. In myasthenia gravis, your immune system produces antibodies that block or destroy many of your muscles' receptor sites for a neurotransmitter called acetylcholine (as-uh-teel-KOH-leen). Your nerves communicate with your muscles by releasing chemicals (neurotransmitters) that fit precisely into receptor sites on the muscle cells at the nerve-muscle junction. In myasthenia gravis, certain receptor sites are blocked or destroyed, causing muscle weakness. Talk to your doctor if you have difficulty:Ĭhemicals messengers, called neurotransmitters, fit precisely into receptor sites on your muscle cells. Weak neck muscles make it hard to hold up your head. Weakness in your legs can affect how you walk. Myasthenia gravis can also cause weakness in your neck, arms and legs. For example, your smile might look like a snarl. The muscles used for chewing might tire halfway through a meal, particularly if you've been eating something hard to chew, such as steak. In some cases, liquids you're trying to swallow come out your nose. You might choke easily, making it difficult to eat, drink or take pills. Your speech might sound soft or nasal, depending on which muscles have been affected. In about 15% of people with myasthenia gravis, the first symptoms involve face and throat muscles, which can: Double vision (diplopia), which may be horizontal or vertical, and improves or resolves when one eye is closed.Drooping of one or both eyelids (ptosis).In more than half of people who develop myasthenia gravis, their first signs and symptoms involve eye problems, such as: However, the symptoms tend to progress over time, usually reaching their worst within a few years after the onset of the disease.Īlthough myasthenia gravis can affect any of the muscles that you control voluntarily, certain muscle groups are more commonly affected than others. Because symptoms usually improve with rest, muscle weakness can come and go. Muscle weakness caused by myasthenia gravis worsens as the affected muscle is used.
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