How Is Myasthenia Gravis Diagnosed?
During a physical exam for myasthenia gravis, your health care provider may look for signs such as having a droopy eyelid, a hard time holding your arms out at shoulder length for a reasonable length of time, or a weak grasp. Blood tests may reveal the presence of other less common antibodies. Specialized tests, such as an electromyography (EMG), use electrical stimulation to measure how your muscles respond. In myasthenia gravis, doctors often use repetitive nerve stimulation during the EMG to check for muscle fatigue.
If you have myasthenia gravis, your muscle strength decreases in a predictable pattern during testing. As part of the exam, your doctor may give you a medication such as neostigmine. If you have the condition, this drug temporarily improves your muscle strength, which helps confirm the diagnosis.
Because other conditions sometimes come with myasthenia gravis and can interfere with treatment, your health care provider may order other tests. You may need a CT scan or an MRI to check for a thymoma. You'll be checked for high blood pressure and glaucoma, and you'll probably have your blood tested to see if you have thyroid disease, other autoimmune diseases (such as rheumatoid arthritis or systemic lupus erythematosus), diabetes, kidney problems, or any infections.
What Are the Treatments for Myasthenia Gravis?
There is no cure for myasthenia gravis, but it is treated with medications and sometimes surgery. Treatments include:
Complement inhibitors:
- Eculizumab (Solaris)
- Ravulizumab (Ultomiris)
- Zilucoplan (Zilbrysq)
FcRn blockers:
- Efgartigimod alfa-fcab (Vyvgart)
- Rozanolixizumab (Rystiggo)
Steroids:
- Prednisone
Immunosuppressive drugs:
- Azathioprine (Imuran)
- Cyclosporine (Neoral)
- Mycophenolate (CellCept)
Acetylcholine-boosting medication:
- Pyridostigmine (Mestinon)
In severe cases, you may need to have your blood sent through a special machine that removes the antibody-containing plasma and replaces it with antibody-free plasma. This is called plasmapheresis. You may also be given a preparation called intravenous immunoglobulin (IVIg) through a needle in a vein.
If you have a thymoma, you will need surgery to remove your thymus (thymectomy). In fact, your doctor may recommend that you have this surgery even if no tumor is present because removal of the thymus seems to improve symptoms in many patients with AChR who do not respond to treatments.
Myasthenic crisis is a sudden worsening of symptoms, often with difficulty breathing and/or swallowing. It is life-threatening and typically requires treatment in the intensive care unit with temporary placement on a respirator. Myasthenic crisis can happen during a severe infection, so you'll probably need to be treated with antibiotics as well.
Situations that affect myasthenia gravis include:
- Changes in thyroid function
- Surgery
- Radiation therapy
- Infection
Certain medications can worsen symptoms of myasthenia gravis, including:
- Certain antibiotics (particularly those called aminoglycosides)
- Narcotic drugs
- Penicillamine
- Magnesium
- Anesthesia
- Muscle relaxants
- Beta-blockers to treat heart arrhythmias
Some women notice that their symptoms get worse around the time of their menstrual period. Pregnancy's effect on myasthenia gravis is unpredictable. About one-third of women have an improvement in their symptoms, one-third have no change, and one-third get worse.
How Can I Prevent Myasthenia Gravis?
There are no known ways to prevent myasthenia gravis. If you already have the condition, take these steps to help keep it from getting worse:
- Try to prevent infections with careful hygiene and by avoiding sick people.
- Treat infections promptly.
- Do not become overheated or too cold.
- Avoid overexertion.
- Learn good ways to deal with stress.
