Pediatric Muscular Dystrophy: Incurable Disease in Children

Introduction:

It is a group of genetic disorders that cause progressive weakening and abnormal muscle function. Even though children can receive a diagnosis at any age, the average age of diagnosis is five years old. Clinical symptoms of muscular dystrophy can present in children by the second year of life.

What Is Muscular Dystrophy in Children?

Dystrophin is a protein that can cause muscular dystrophy in children. Dystrophin is a protein essential for maintaining muscle strength. There are more than 30 different forms of mild or severe muscular dystrophy. However, Duchenne and Becker muscular dystrophy are two common types in children.

Muscular dystrophy is a disorder that runs in families. The faulty gene can be transferred to children even if the adults seem in good condition and show no sickness symptoms. Consequently, the offspring are more likely to contract the condition. Children with the disorder have progressive worsening of muscle issues, and the rate of progression can vary between each child.

What Role Does Gender Play in Muscular Dystrophy?

1. Boys

• Male children are more likely to acquire Duchenne and Becker muscular dystrophy. Duchenne muscular dystrophy has X-linked inheritance as the disease causes an abnormal mutation in the X chromosome. Males are born with one copy of the X and another of the Y chromosome.

• Boys have a higher risk for the disease since they possess only one X chromosome. They do not have any extra chromosomes to compensate for the mutation of the X chromosome.

1. Girls

Healthy women, also known as carriers, have a 50 % risk of passing on altered X chromosomes to their offspring. Therefore, it can cause positive muscular dystrophy results in sons. Whereas daughters have a 50 % chance of developing and inheriting mutated X chromosomes. The daughters might not be affected by the disorder as they can obtain one set of healthy X chromosomes from the father.

What Are the Symptoms of Pediatric Muscular Dystrophy?

Some signs and symptoms are:

1. Duchenne Muscular Dystrophy

It is the most common type of muscular dystrophy in boys, but less frequent in girls.

• Frequent falls.

• They have trouble getting up from sitting or slowly raising their hands to steady their legs while standing (Gower's sign).

• Need help running, jumping, or walking.

• Waddling gait.

• Walking on toes.

• Large calf muscle.

• Pain in muscles and stiffness.

• Learning difficulties.

• Delayed growth.

• Difficulty swallowing.

• Heart failure and abnormal heartbeat.

• Abnormal curving of the spine.

• Difficulty breathing.

1. Becker Muscular Dystrophy

This variant's indications and symptoms are comparable to Duchenne's but milder and develop more slowly. The symptoms of Becker type develop during teenage years but clinically manifest during mid-twenties.

What Are the Other Types of Muscular Dystrophy?

The muscular dystrophy is further divided into the following categories according to the location of symptoms or a specific characteristic:

1. Myotonic: Children affected by this disease type cannot relax their muscles after contractions. Facial and neck muscles are commonly affected. Children with this disorder have the characteristic appearance of long and thin faces, drooping eyelids, and swan-like necks.

2. Facioscapulohumeral (FSHD): Muscle weakness initially develops in the face, hip, and shoulders. When the arms are elevated, the shoulder blades may appear protruded like wings. The symptoms can present in childhood, teenage years, or late in the 50’s.

3. Congenital: This type affects both boys and girls equally and is diagnosed at birth or before two years. In some patients, the condition progresses slowly and causes mild disease, but for others, disease progression is rapid with severe impairment.

4. Limb-Girdle: In this type, the hip and shoulder are affected initially. Children with this disorder cannot lift the front part of the foot and fall frequently. The condition develops during childhood or teenage years.

How Is Muscular Dystrophy Diagnosed in Children?

If muscular dystrophy is suspected, seeking medical care is necessary. A medical expert may request the following tests to confirm the diagnosis:

• Enzyme Blood Tests: These tests quantify the amount of blood-borne creatine kinase produced by injured muscles. A higher creatine kinase level is suggestive of muscular dystrophy.

• Gene Testing: This method looks for potential muscular dystrophy-causing genes.

• Muscle Biopsy: A small muscle sample is visualized under a microscope to diagnose muscular dystrophy. The test helps differentiate muscular dystrophy from other disorders.

• Electromyography: In this procedure, a needle is inserted into muscles to check their response to electrical signals during muscle relaxation and contraction.

• Echocardiogram: The procedure is done to get ultrasound cardiac images and assess the condition of the heart.

• Lung-Monitoring Tests: It helps to monitor lung function.

How Are Muscular Dystrophy in Children Treated?

A comprehensive cure for muscular dystrophy is not possible. However, some medications and treatment options can help manage the disease, improve mobility, and help with heart and lung muscle strength. Muscular dystrophy is a disorder that requires life-long care and monitoring.

Corticosteroids such as Prednisone and Deflazacort can improve muscle strength and slow disease progression. However, long-term use of these medications can cause weight gain, bone weakening, and enhanced fracture risk.

A newer drug, Eteplirsen, approved by the Food and Drug Administration (FDA) is available that helps stimulate dystrophin production in children with Duchenne. In 2019, the FDA approved Goodison for treating children with Duchenne muscular dystrophy caused by specific mutations. Angiotensin-converting enzyme inhibitors or beta blockers are advised for children with heart conditions.

Physical and respiratory therapy for patients can help improve their quality of life. Other supportive measures are exercises, braces, or mobility aids.

What Are the Complications of Muscular Dystrophy in Children?

• Children might need wheelchairs as they develop trouble walking.

• If muscles in the shoulder or arms get affected, it can interfere with daily activities.

• Muscles or tendons around the joint can shorten (contracture), leading to limited mobility.

• Progressive weakness of respiratory muscles can affect breathing. Later, children affected by muscular dystrophy might need a ventilator, initially at night and eventually during the day.

• Weakening of back muscles can be inept to hold the spine straight.

• Heart muscle efficiency reduces with disease progression.

• If muscle associated with swallowing gets affected, it could cause nutritional problems and aspiration pneumonia. Therefore, feeding tubes might be helpful.

Conclusion

Muscular dystrophy is an extremely challenging disease to diagnose and treat. The disease causes progressive weakness and skeletal muscle degeneration. The condition worsens with time, and most eventually lose their walking ability. However, some treatment options are available to cope with the disease and slow its progression.