There are several myasthenia gravis tests that doctors can perform to see whether someone is affected with the disease. There are four main tests used to help verify the presence of the disease: a blood test, an edrophonium chloride test, a single-fiber electromyogram (EMG) and repetitive nerve simulation. In addition, a computed tomography (CT) scan or magnetic resonance imaging (MRI) can be used to rule out the possibility of other medical problems.
Myasthenia gravis is an autoimmune neuromuscular disease. The main symptom is that the voluntary muscles in the body feel weak after activity, but after resting, the weakness is decreased. The reason for the weakness is that the nerves and muscles do not communicate properly because there is a defect in nerve impulse transmission. As an autoimmune disease, this condition causes the immune system to attack the nerve receptors. The symptoms of the disease can most often be seen in the face, especially the eyes and eyelids. People who have this disease might also have difficulty swallowing.
One of the myasthenia gravis tests is a blood test that measures acetylcholine receptor antibodies. The antibodies are what the immune system sends to attack the acetylcholine receptor, which is why the nerves and muscles have problems communicating. If there are a high number of antibodies, myasthenia gravis is a possible diagnosis.
Another of the myasthenia gravis tests is the edrophonium chloride test. In this test more invasive test, edrophonium chloride is injected into the vein of a patient. If after the drug is injected there is an improvement in strength in the eye muscles or speech, this could be an indicator of myasthenia gravis. Another invasive test is an EMG, during which an electrode is inserted into the body to see how well the nerves and muscles communicate. The electrode is actually a recording needle, and the test is generally performed on the forearm muscle or forehead of the patient.
The last of the myasthenia gravis tests is repetitive nerve simulation. This test also involves an electrode, but it is less invasive than the EMG because it is placed on the skin, over a muscle. The results of this test can also indicate myasthenia gravis.
Neurologists might also conduct a CT scan or an MRI to rule out other possible diseases. One of the main effects of myasthenia gravis is muscle weakness, so it can be mistakenly diagnosed. That is also one reason that there are four myasthenia gravis tests available to help diagnose the disease.
