Myasthenia gravis (MG) in children

What is myasthenia gravis (MG) in children?

Myasthenia gravis (MG) is an autoimmune disorder, a condition where immune cells mistakenly attack healthy tissue. It affects the muscles in different parts of the body. Immune cells disrupt the communications between nerves and muscles, causing the muscles to weaken.

Myasthenia gravis (MG) is referred to as a "snowflake disease", because each person experiences if differently.

Myasthenia gravis can occur at different ages. A child’s eyelids may start to droop, or they may start having trouble moving their eyes. Next, they may start having problems chewing and swallowing as well as using their arms and legs and even breathing.

Children with myasthenia gravis may feel fine in the morning and may be very tired by the end of the day. If the condition is not well controlled, they may have serious events called myasthenia crises in which they get very sick and may have trouble breathing.

What are the different types of myasthenia gravis (MG) in children?

Myasthenia gravis is divided into types based on the age of the patient and whether it primarily affects the eyes or other parts of the body.

• Generalized myasthenia gravis affects muscles throughout the body. It can start in childhood or later in life.

• Ocular myasthenia gravis only affects the eyes, but a large portion of people with this form of myasthenia gravis will eventually develop the generalized form. Like generalized myasthenia gravis, the ocular type can start in childhood or later in life.

What are the signs and symptoms of myasthenia gravis (MG) in children?

A child with myasthenia gravis may experience the following symptoms:

• Eyelids that droop in one or both eyes

• Weak eye muscles in one or both eyes

• Fatigue, especially later in the day

• Symptoms that can change during the day

• Weak neck muscles

• Weakness in the arms and legs

• Difficulties chewing and swallowing

• Difficulties breathing

How is myasthenia gravis (MG) in children diagnosed?

Different steps may be needed to diagnose myasthenia gravis in children.

The various steps we take to diagnose myasthenia gravis at Children’s Health include:

• We start with a physical exam, looking for key signs and symptoms.

• We usually test a sample of your child’s blood for certain antibodies, which play an important role in the immune system. We often test for several antibodies, which can involve taking a series of blood samples.

• We also may use a nerve conduction test called repetitive nerve stimulation to see if your child gets weaker when they use a set of muscles over and over.

What causes myasthenia gravis (MG) in children?

We know that myasthenia gravis is an autoimmune disease, but it isn’t clear why some people get the disease and others don’t.

The thymus, a big gland in the chest, is believed to play a role in myasthenia gravis. Some families also tend to get autoimmune conditions.If someone in your family has an autoimmune disorder, your child may also have an increased risk.

How is myasthenia gravis (MG) in children treated?

We may prescribe different medications to treat myasthenia gravis in children. Some treat the symptoms of the disease, while others slow down (suppress) the immune response.

Medication:

• Mestinon® which treats the symptoms of myasthenia gravis

• Prednisone which is used to suppress the immune system in autoimmune disorders

• Intravenous immunoglobulin (IVIG) which consists of immune proteins (immune globulins) and is used to affect the immune system’s response

Procedures:

• Plasmapheresis in which a child’s blood is run through a machine and cleaned of some antibodies

• Thymectomy the surgical removal of the thymus gland