When we think of an autoimmune condition like myasthenia gravis (MG), we might assume it only affects middle-aged adults. But MG can develop at any age, even in children. It occurs when the immune system disrupts the connection between nerves and muscles, leading to weakness that makes movement harder. Think of it like a miscommunication problem at a busy intersection, preventing signals from getting through. When this happens, the muscles don’t get the right messages, making everyday movements more difficult.

MG is rare in children, accounting for about 10 percent to 15 percent of all cases. While uncommon, it’s important to recognize and diagnose early. This article reviews key facts about MG in children.

What Causes MG in Children?

MG happens when the immune system doesn’t work properly. Normally, immune cells produce antibodies that help protect the body from viruses and bacteria. But in people with MG, the immune system creates autoantibodies that attack the signals nerves use to control muscles. As a result, the muscles weaken and may not work as they should.

Instead of fighting off germs, these autoantibodies block important chemicals like acetylcholine or proteins such as muscle-specific kinase (MuSK), which nerves need to control muscle movement.

Many children with MG have an abnormally large or overactive thymus gland, a small organ in the upper chest that helps regulate the immune system. Researchers believe this may contribute to MG by triggering the production of autoantibodies that disrupt nerve-muscle communication, but its exact role is still being studied.

The cause of MG in children is unknown. Babies born to mothers with MG can temporarily have the condition because the mother’s antibodies pass to them during pregnancy. This is called transient neonatal MG, and it usually goes away within a few weeks. However, having a mother with MG does not increase a child’s risk of developing juvenile MG later in life.

Types of MG in Children

There are a few types of MG found in children:

• Transient neonatal MG
• Congenital MG
• Juvenile MG

Transient Neonatal MG

Transient neonatal MG is a temporary form of MG that may develop in babies born to mothers with MG. Babies with transient neonatal MG don’t make their own MG antibodies. Instead, antibodies from the mother can pass through the placenta during pregnancy, leading to muscle weakness, poor suckling, and other symptoms seen after birth. Eventually, these antibodies break down, and symptoms go away.

Congenital MG

Congenital MG is a very rare form of MG that usually starts at birth, but unlike some other types, it doesn’t go away on its own. The symptoms may be similar to other forms of MG, but it’s different because it’s inherited rather than caused by the immune system.

Juvenile MG

Juvenile MG affects children and teens younger than 18. This type is the closest to MG, typically found in adults. The rest of this article will focus on juvenile MG.

Symptoms of MG in Children

The most common symptom of juvenile MG in children is muscle weakness. It can affect a few or several muscles and range from mild to severe. Muscle weakness can be observed as:

• Droopy eyelids, potentially leading to double vision and making it hard to see clearly
• Trouble chewing and swallowing
• Abnormal tiredness even after little physical activity
• Shortness of breath
• Difficulty speaking
• Clumsiness and frequent falls

Because MG symptoms can come and go, some adults may mistake them for laziness or clumsiness. However, these symptoms are real and can vary from child to child.

What Is a Myasthenic Crisis?

Myasthenic crisis is a serious, life-threatening weakness of the muscles involved in swallowing or breathing in people with MG. It’s a medical emergency. According to one study, about 10 percent of children with juvenile MG experience myasthenic crises.

Myasthenic crisis symptoms include severe shortness of breath, difficulty swallowing, drowsiness, and extreme weakness. A child having a myasthenic crisis needs immediate hospital care in a pediatric intensive care unit (PICU).

How Is MG in Children Diagnosed?

The diagnosis of juvenile MG requires an extensive physical exam, as well as additional testing. Your child’s healthcare provider will likely ask about their symptoms and family medical history.

Tests to diagnose MG include:

• Bloodwork for checking for abnormal MG antibodies in the blood
• Electromyography (EMG) to test the electrical activity of the muscles
• Nerve stimulation testing to detect abnormal communication between the muscles and the nerves
• Genetic testing to exclude congenital MG
• Imaging studies, such as an MRI or a CT scan, which help detect any potential abnormalities of the thymus

Treatment Options

While there is no cure for MG, treatments can help manage the symptoms. A specialist can recommend the best approach based on your child’s needs.

Medications prescribed and procedures recommended to manage the symptoms of MG in children may include acetylcholinesterase inhibitors and immunosuppressants.

Acetylcholinesterase Inhibitors

Acetylcholinesterase inhibitors, such as pyridostigmine (Mestinon), increase the availability of acetylcholine, helping the nerves and muscles communicate. Their side effects include upset stomach, diarrhea, and cold sweats.

Immunosuppressants

Immunosuppressants, such as corticosteroids (steroids), change or shut down the abnormal immune system response. Used long term, steroids are known to cause side effects related to growth problems and obesity.

Other immunosuppressant drugs used for juvenile MG may include:

• Azathioprine
• Cyclophosphamide
• Cyclosporine
• Mycophenolate mofetil
• Rituximab
• Tacrolimus

A doctor may also recommend intravenous immunoglobulin (IVIG), which involves an infusion of normal antibodies collected from donors. IVIG can also help calm down autoimmune reactions. IVIG may cause headaches, nausea, and, in rare cases, more serious reactions like blood clots or kidney problems.

Procedures

Plasmapheresis, a procedure that removes abnormal antibodies and replaces plasma with a substitute like donor plasma or a sterile protein solution, may be recommended.

In certain cases, a doctor may recommend thymectomy, a surgery to remove the thymus gland.

Studies show that thymectomy is linked to better long-term MG outcomes, but it does not guarantee full remission (complete disappearance of symptoms).

Outlook for Juvenile MG

MG is usually a lifelong condition with no cure, but advances in treatment have made it more manageable. This allows many children with MG to live a long and full life with adequate medical care.

MG may go in and out of remission, but the goal is long-term symptom relief.

As your child gets older, they may face new challenges. Having a reliable team of specialists — such as neurologists, eye doctors, pediatricians, and surgeons — can provide the care and support they need.

Supporting Your Child With MG

Parents can take steps to support their child with MG. Simple actions like planning the day around their energy levels and ensuring they get enough rest may help manage symptoms. A balanced diet with plenty of fruits and vegetables, along with regular activity that accounts for fatigue, can also help.

MG affects more than just physical health — it can also impact emotional and mental well-being. In fact, adults with MG have higher rates of depression and anxiety. Creating a safe, supportive environment can help boost confidence and encourage self-expression.

Talk With Others Who Understand

On MGteam, the social network for people with myasthenia gravis and their loved ones, members come together to ask questions, give advice, and share their stories with others who understand life with myasthenia gravis.

Has your child been diagnosed with juvenile MG? How do you help them cope? Share your experience in the comments below, or start a conversation by posting on your Activities page.