How to diagnose myasthenia gravis

Under the surface of human skin, there are not only various bone joints, but also muscle cells. When we want to carry out daily activities, we often use muscles to drive bones to move. However, many people have experienced sudden muscle weakness, and in severe cases, even myasthenia gravis symptoms. However, muscle weakness may be caused by many reasons. So how should myasthenia gravis be diagnosed?

Examination items: blood routine, urine routine, general cerebrospinal fluid examination

1. Neostigmine test

Adults generally use 1-1.5 mg of neostigmine injected intramuscularly. If the symptoms improve 10-15 minutes after injection, reach a peak in 30-60 minutes, and last for 2-3 hours, the neostigmine test is positive.

2. Thymus CT and MRI

Thymic hyperplasia or thymoma may be detected, and enhanced scanning should be performed if necessary to further clarify the diagnosis.

3. Repeated electrical stimulation

Repeated electrical nerve stimulation is a commonly used examination method with diagnostic value. Electrodes are used to stimulate motor nerves and record the amplitude of the muscle's response potential. If the patient's muscle potential gradually declines, it indicates the possibility of a lesion at the neuromuscular junction.

4. Single Fiber Electromyography

Single-fiber electromyography is a more sensitive means of detecting abnormalities in neuromuscular junction conduction than repetitive nerve electrical stimulation. Abnormalities in neuromuscular transmission can be detected by increased "tremors" during repeated electrical nerve stimulation and when clinical symptoms are normal. It has the highest sensitivity of all muscle weakness tests.

5. Detection of acetylcholine receptor antibody titer

The detection of acetylcholine receptor antibody titer is of characteristic significance for the diagnosis of myasthenia gravis. Serum acetylcholine receptor antibodies can be detected in 80% to 90% of systemic myasthenia gravis and 60% of ocular myasthenia gravis. The level of antibody titer is not completely consistent with the severity of clinical symptoms.