Myasthenia gravis is a chronic autoimmune disorder in which antibodies attack normal receptors on muscle, leading to disrupted communication in the junction between terminal end of nerve fibers and muscles. This blocks the neurotransmitter from stimulating muscle contraction leading to weakness of body muscles.
Symptoms
- Eye muscle weakness such as drooping eyelid(s) and double vision
- Facial and oropharyngeal muscle weakness such as trouble pronouncing words or nasal sound, chewing and swallowing difficulty
- Arm and leg muscle weakness such as problems climbing up stairs or lifting arms to shampoo hair
- Respiratory muscle weakness such as shallow, ineffective breathing
The muscle weakness often occurs at certain time of a day such as in the afternoon or when patients engage in activities which require prolonged use of muscles. Patients may also experience muscle fatigue.
Diagnosis
Making the diagnosis involves taking medical history, physical exam, laboratory test, and electro-diagnostic study called repetitive nerve stimulation. In some patients, needle EMG or single fiber EMG test to measure electrical activity of a muscle may be required to detect abnormality due to neuromuscular conditions or primary muscle disease. The electro-diagnostic tests give accurate diagnosis.
Treatment
Medications can be classified into 2 groups. The first medication group helps to increase neurotransmitter function including cholinesterase inhibitors such as pyridostigmine. The next group is immunosuppressant such as corticosteroid, azathioprine, and mycophenolate mofetil.
Surgery is recommended for patients with tumor of thymus gland found on chest CT scan.
Recommendation
Normally, patients can lead normal or near normal lives but should avoid exposure to hot weather, prolonged strenuous activities, and not getting adequate rest. When seeing healthcare providers, make sure they are informed about your condition and symptoms because certain medicines may interfere either with the disease or the action of the medicines you take for myasthenia gravis.
