You have been told that your child has myasthenia gravis (MG). This condition causes your child’s muscles to become weak. MG is a serious condition. But it can be managed. With treatment, your child can still live an active and healthy life.
MG happens due to problems with the connections between nerves and muscles. These are called neuromuscular junctions. With MG, the body’s immune system makes abnormal antibodies (disease-fighting substances) that attack at the neuromuscular junction. This keeps the nerves from sending signals to the muscles they control. As a result, the muscles do not work properly. MG is not a hereditary disorder and is therefore not usually passed on through generations. There is a form of MG where the antibodies are transferred to the infant from the mother. This usually causes short-lasting symptoms, which then resolve.
The main symptom of MG is muscle weakness. This muscle weakness can range from mild to severe. Depending on which muscles are affected, MG may cause:
Droopy eyelids (ptosis)
Weakness of eye movements, which can cause double vision
Weakness in the neck, arms, and legs
Trouble chewing and swallowing
Trouble feeding (only infants)
Muscle weakness increases during activity and improves after rest
Your child will likely be referred to a pediatric neurologist. This is a healthcare provider with special training to find and treat problems that affect the nervous system. The healthcare provider will ask about your child’s health history and symptoms. The healthcare provider will also examine your child. Your child’s muscle strength will be checked. Skills, such as vision, chewing, and swallowing will also be checked. Tests will be done to confirm the problem as well. These can include:
A nerve conduction study (NCS). This helps check nerve and muscle function. Electrodes (small round discs attached to wires) are placed on the skin over certain nerves and the muscles they control. A brief electrical current is sent to the nerves. The time it takes for the muscles to respond to the nerves is then recorded.
Electromyogram (EMG). This is often done with a nerve conduction study. It also helps checks nerve and muscle function. Small needle electrodes are placed into muscles in the arms or legs. The electrical activity of the muscles is recorded when the muscles are active and when they are at rest.
Blood tests. These help check for certain cells or antibodies in the blood that are only present with MG. For these tests, a sample of blood is taken from a vein.
Edrophonium test. This test helps check muscle strength. Medicine called edrophonium is injected into a vein. If a person has MG, the medicine will cause a brief increase in muscle strength. For instance, the person’s eyelids may be less droopy for a short time.
Treatment for MG will vary for each child. Treatments can include:
Medicines. These help improve muscle weakness. Some medicines treat the problems at the neuromuscular junction. Others help prevent the immune system from making abnormal antibodies.
Plasma exchange and high-dose IVIG. These treatments involve the use of special blood products. They help fight the body’s abnormal immune response or clear the abnormal antibodies from the bloodstream.
Surgery to remove the thymus gland. The thymus gland lies beneath the breastbone. It is involved in the immune system. In a person with MG, the thymus gland is more likely to be enlarged or abnormal. In some cases, removing the gland may improve symptoms or even make them go away. The healthcare provider will tell you more about this treatment, if needed.
MG is a chronic (long-lasting) condition. To help prevent problems, ongoing care is needed. This means your child needs to have regular checkups with the healthcare provider. Your child may also need to take medicines daily to help control symptoms. Your child may also be prescribed supportive care, if needed. This can include speech, physical, or occupational therapy.
Patients with MG are at risk for a medical emergency when the lung muscles weaken to the point that your child is not able to breathe on his or her own and may need assistance breathing (myasthenic crisis). This may be triggered as a side effect from a new medicine, or by other infections or fever.
Accepting your child’s diagnosis can be difficult. Talking with a counselor may help you and your child work through your feelings. Joining a support group may also help. These groups give your child the chance to meet other children with MG. They also allow you to talk to other parents who are coping with their child having MG. For more information about MG, contact the: Myasthenia Gravis Foundation of America, www.myasthenia.org.