Myasthenia Gravis (MG) in Children
What is myasthenia gravis in children?
Myasthenia gravis (MG) is a disorder that causes weakness in muscles around the body.
This happens because antibodies destroy some of the places where nerves and muscles
meet (neuromuscular connections). MG affects the voluntary muscles of the body. It
mostly affects the eyes, mouth, throat, arms, and legs. It most often affects adults,
but can sometimes happen in children.
There are 3 types of MG in children:
Transient neonatal MG
This is a temporary form of MG. It can happen in babies born to mothers with MG. It
occurs when antibodies from MG cross over to the baby growing in the mother’s uterus.
Transient neonatal MG usually lasts only a short time. The symptoms go away weeks
or months after birth, as the antibodies are naturally replaced. Babies are not at
greater risk of developing MG later in life.
This is an autoimmune disorder. It most often occurs in white teen girls. It is a
lifelong condition that may go in and out of remission. About 1 in 10% cases of MG
in children are juvenile MG. Treatment is often done by removing the entire thymus
gland. This may cure the disorder.
This is a very rare form of MG. It is not an autoimmune disorder. It is inherited
as an autosomal recessive disease. This means that both boys and girls are equally
affected. It also means that 2 copies of the gene, 1 inherited from each parent, are
needed to have the condition. There are about 12 rare genetic disorders that may cause
congenital MG. Symptoms of congenital MG usually start at birth and are lifelong.
Some forms may be treated with the same medicines that are used for adults.
What causes myasthenia gravis in a child?
Myasthenia gravis is not contagious. This means it can’t be spread from person to
person. It may be acquired through immune proteins or antibodies to babies born to
mothers with MG. Or the disorder may develop by chance later in childhood. Rare forms
of MG are caused by gene changes.
Which children are at risk for myasthenia gravis?
A child is more at risk for myasthenia gravis if he or she has a mother with MG, or
parents with certain gene changes.
What are the symptoms of myasthenia gravis in a child?
Symptoms can occur a bit differently in each child, and vary by type of MG. They can
Transient neonatal MG
Babies may be weak and have poor sucking. They may have breathing problems. In some
cases, a baby’s respiratory muscles are so weak the baby can’t breathe on his or her
own. Then the baby may need the help of a mechanical breathing machine (ventilator).
Symptoms go away as the mother’s antibodies disappear over time.
Symptoms may start slowly over weeks or months. A child may become very tired after
very little activity. He or she may start to have trouble with chewing and swallowing.
Drooping eyelids may be so severe that the child can’t see. The symptoms tend to be
milder in the morning and worse later in the day.
The symptoms are usually noted at birth, but may begin in the first year. They include
overall weakness in the arms and legs. Babies may have delays in motor skills such
as crawling, sitting, and walking. They may have trouble feeding or breathing. And
they may have weak eyelids and poor head control.
The symptoms of myasthenia gravis can be like other health conditions. Make sure your child
sees his or her healthcare provider for a diagnosis.
How is myasthenia gravis diagnosed in a child?
The healthcare provider will ask about your child’s symptoms and health history. He
or she may also ask about your family’s health history. He or she will give your child
a physical exam. Your child may also have tests, such as:
- Electromyogram/nerve conduction study (EMG/NCS). This is a test that measures the electrical activity of a muscle or a group of muscles.
This is the main way to diagnose MG. An EMG/NCS can detect abnormal electrical muscle
activity. Your child may be given a medicine during the test. This may be an anticholinesterase
inhibitor such as neostigmine or pyridostigmine. It may be given by mouth or injected.
In some cases, a single-fiber EMG test may be done. This is a more sensitive test.
It may not be done in as many healthcare centers.
- Blood tests. These check for certain kinds of antibodies in the blood.
- Genetic tests. These tests look for conditions that tend to run in families.
How is myasthenia gravis treated in a child?
Treatment will depend on your child’s symptoms, age, and general health. It will also
depend on how severe the condition is, and the type of MG.
Transient neonatal MG goes away on its own in weeks or months. There is no cure for
juvenile or congenital MG, but the symptoms may be controlled. It is usually a lifelong
A child may need:
- Breathing support. Your child may need a mechanical breathing machine (ventilator) to breathe.
- Nutritional support. If your child has swallowing problems, he or she may need tube feeding or other care.
Treatment may also include any of these:
- Medicines. These include cholinesterase inhibitors, steroids, and immunosuppressants.
- Thymectomy. This is surgery to remove the thymus gland. The role of the thymus gland in autoimmune
MG is not fully understood. A thymectomy may or may not improve a child's symptoms
or cure MG. The results of the antibody tests may help your child’s healthcare provider
assess if a thymectomy may help.
- High-dose intravenous immune globulin. This is a procedure to add a large amount of normal antibodies from donated blood
into the child’s bloodstream.
- Plasmapheresis. This is a procedure to remove abnormal antibodies from the blood and replace them
with normal antibodies from donated blood.
Talk with your child’s healthcare providers about the risks, benefits, and possible
side effects of all treatments.
What are the possible complications of myasthenia gravis in a child?
In severe cases, a child may need a breathing machine (ventilator) to help with breathing.
How can I help prevent myasthenia gravis in my child?
Talk with your healthcare provider if you are pregnant and have MG. Your healthcare
provider may advise genetic counseling. You can learn more about the risk of MG in
a future pregnancy.
How can I help my child live with myasthenia gravis?
Issues can revealed as a child grows and develops. Children with myasthenia gravis
need to see their healthcare team often.
You can help your child strengthen his or her self-confidence and be as independent
as possible. The healthcare team will talk with you about the best ways to help your
When should I call my child’s healthcare provider?
Call the healthcare provider if your child has:
- Symptoms that don’t get better, or get worse
- New symptoms
Key points about myasthenia gravis in children
- Myasthenia gravis (MG) is a disorder that causes weakness in muscles around the body.
It mostly affects the eyes, mouth, throat, arms, and legs.
- Transient neonatal MG is a temporary form of MG. It can happen in babies born to mothers
with MG. The symptoms go away weeks or months after birth.
- Juvenile MG is an autoimmune disorder. It is a lifelong condition that may go in and
out of remission.
- Congenital MG is a very rare form of MG that is inherited. Symptoms usually start
at birth and are lifelong.
- Treatment may include medicines, surgery, or blood product infusions. In severe cases,
a child may need a breathing machine (ventilator) to help with breathing.
- Issues can revealed as a child grows and develops. Children with myasthenia gravis
need to see their healthcare team often.
Tips to help you get the most from a visit to your child’s healthcare provider:
- Know the reason for the visit and what you want to happen.
- Before your visit, write down questions you want answered.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
or tests. Also write down any new instructions your provider gives you for your child.
- Know why a new medicine or treatment is prescribed and how it will help your child.
Also know what the side effects are.
- Ask if your child’s condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if your child does not take the medicine or have the test or procedure.
- If your child has a follow-up appointment, write down the date, time, and purpose
for that visit.
- Know how you can contact your child’s provider after office hours. This is important
if your child becomes ill and you have questions or need advice.