WordNet
n. a chronic progressive disease characterized by chronic fatigue and muscular weakness (especially in the face and neck); caused by a deficiency of acetylcholine at the neuromuscular junctions [syn: myasthenia]
Wikipedia
Myasthenia gravis (MG) is a long term neuromuscular disease that leads to varying degrees of muscle weakness. The most commonly affected muscles are those of the eyes, face, and swallowing. It can result in double vision, drooping eyelids, trouble talking, and trouble walking. Onset can be sudden. Those affected often have a large thymus gland or develop a thymoma.
Myasthenia gravis is an autoimmune disease which results from antibodies that block acetylcholine receptors at the junction between the nerve and muscle. This prevents nerve impulses from triggering muscle contractions. Rarely an inherited genetic defect in the neuromuscular junction results in a similar condition known as congenital myasthenia. Babies of mothers with myasthenia may have symptoms during their first few months of life, known as neonatal myasthenia. Diagnosis can be supported by blood tests for specific antibodies, the edrophonium test, or nerve conduction studies.
Myasthenia gravis is generally treated with medications known as acetylcholinesterase inhibitors such as neostigmine and pyridostigmine. Immunosuppressants, such as prednisone or azathioprine, may also be used. The surgical removal of the thymus gland may improve symptoms in certain cases. Plasmapheresis and high dose intravenous immunoglobulin may be used during sudden flares of the condition. If the breathing muscles become significantly weak, mechanical ventilation may be required.
Myasthenia gravis affects 50 to 200 per million people. It is newly diagnosed in 3 to 30 per million people each year. Diagnosis is becoming more common due to increased awareness. It most commonly occurs in women under the age of 40 and in men over the age of 60. It is uncommon in children. With treatment most of those affected lead relatively normal lives and have a normal life expectancy. The word is from the Greek μύς "muscle" and asthenia "weakness", and the "serious".
Usage examples of "myasthenia gravis".
There is a disease known as myasthenia gravis, characterized by muscle weakness, in which there is too-rapid destruction of acetylcholine.
You haven't suddenly acquired an interest in myasthenia gravis, have you?
Chuck wondered briefly if the poor kid had myasthenia gravis, like Waldo in Heinlein's story.
Diseases like myasthenia gravis which involve profound muscle weakness are often related to disturbances in neurotransmitter release, uptake, or clearance.