In order to make a myasthenia diagnosis, the doctor will need to review the patient's medical history, perform physical and neurological exams, and look for symptoms such as muscle weakness. Because muscle weakness can be a symptom of many other disorders, it can be difficult to properly diagnose myasthenia gravis -- a delay in diagnosis of one or two years is not uncommon. Tests that are used to confirm a myasthenia diagnosis include a blood test, edrophonium test, and nerve conduction study.
Weakness is a common symptom of many disorders, which is why myasthenia gravis is often misdiagnosed in people who experience mild weakness or in people whose weakness is restricted to only a few muscles. Therefore, a delay in diagnosis of one or two years is not unusual in cases of myasthenia gravis.
In order to diagnose myasthenia gravis, doctors will need to:
- Review the patient's medical history
- Review the patient's physical and neurological examinations
- Look for symptoms such as impairment of eye movements or muscle weakness.
Tests that are used to confirm a myasthenia diagnosis include:
- Blood test
- Edrophonium test
- Nerve conduction study
- Single fiber electromyography (EMG)
- Computed tomography (CT) scan
- Pulmonary function test (PFT).
A special blood test can detect the presence of immune molecules or acetylcholine receptor antibodies. Most patients with myasthenia gravis will have abnormally elevated levels of these antibodies. However, antibodies may not be detected in patients with only ocular forms of the disease.
(Click Ocular Myasthenia Gravis for more information.)