Neuromuscular Disorders

Types of Neuromuscular Disorders in Children

Neuromuscular disorders in children (also sometimes called “NMDs”) come in many forms, with different symptoms, causes, treatments and long-term outlooks. Some are genetic (inherited) and some are acquired (they develop during childhood). We strive to understand the cause of your child’s motor issues through our expertise and diagnostic tests.

There are several categories of neuromuscular disorders in children, including:

Motor neuron disease (involving the cells that control muscle activity)

• spinal muscular atrophy (an inherited condition that causes nerve cells in the lower part of the brain and spinal cord to break down)

Peripheral nerve disorders (involving the nerves outside the spinal cord)

• Charcot-Marie-Tooth (or “CMT”) disease (a group of related conditions, usually inherited, that affect the nerves leading to the lower legs and feet, and lower arms and hands)
• chronic inflammatory demyelinating polyneuropathy (or “CIDP,” a condition involving damage to the myelin sheath, the covering that surrounds nerve fibers)

Neuromuscular junction disorders (involving malfunctions of the synpases, the space between the nerves and muscles)

• myasthenia gravis (an autoimmune disease that interferes with the chemical transmission of nerve impulses)
• congenital myasthenic syndrome (characterized by muscle weakness that worsens with physical activity)
• botulism (a rare condition caused by nerve toxins produced by the bacteria Clostridium botulinum)

Myopathies (disorders that result in weakness of the muscles)

• congenital myopathies (a group of disorders involving muscle weakness that appear during infancy, including central core disease, myotubular myopathy, nemaline and other kinds of myopathy)
• inflammatory myopathies (chronic muscle inflammation that leads to weakness, including dermatomyositis, polymyosistis and inclusion body myositis)
• metabolic myopathies (the inability of muscle cells to make enough energy to move, including carnitine deficiency, hyper- and hypokalemic periodic paralysis, McArdle disease, Pompe disease and mitochondrial myopathy)

Muscular dystrophies (genetic, degenerative diseases of the muscle)

• Becker muscular dystrophy (a disorder characterized by slowly progressing weakness of the legs and pelvis)
• Duchenne muscular dystrophy (a disorder that only affects boys and is caused by a defective gene for dystrophin, a protein necessary for muscle movement)
• congenital muscular dystrophy (muscular dystrophy that’s present at birth)
• distal muscular dystrophy (a group of muscular dystrophies that affect the distal muscles — those farthest from the hips and shoulders — including the lower arms, hands, lower legs and feet)
• Emery-Dreifuss muscular dystrophy (a condition that mainly affects the skeletal and heart muscles)
• fascioscapular humeral muscular dystrophy (weakness that typically affects the muscles of the face, shoulders and upper arms)
• limb-girdle muscular dystrophy (a group of disorders affecting the muscles around the hips and shoulders)
• oculopharyngeal muscular dystrophy (muscle weakness that begins in adulthood and typically causes droopy eyelids and trouble swallowing)

Myotonic disorders (difficulty in relaxing muscles after they contract)

• myotonic dystrophy types I and II (disorders that begin in adulthood and cause prolonged muscle contractions — for example, an inability to release a grip)
• paramyotonia congenita (involves periods of muscle tensing — usually affecting the face, neck, arms and hands — that worsen after activity or in the cold)

Other neuromuscular disorders in children

• Friedreich’s and other kinds of ataxia (difficulty controlling voluntary muscle movements)

Most of these conditions are treatable but not yet curable. A few (including chronic inflammatory demyelinating polyneuropathy, Pompe disease and certain other metabolic myopathies) can be cured.

Symptoms of Neuromuscular Disorders in Children

Each neuromuscular disorder has its own set of initial symptoms. The most common symptoms include:

• weakness or “floppiness” in infants
• a change in muscle tone, strength or size
• delay in reaching motor skills, or a loss of previously acquired milestones
• frequent tripping or falling
• difficulty going up stairs or rising to a stand
• abnormal gait (such as toe walking or waddling)
• muscle cramping or twitching
• a tingling or numb sensation
• difficulty breathing or feeding
  vision problems

Often, these symptoms may worsen over time.

Diagnosing Neuromuscular Disorders in Children  

With all these different varieties, the right diagnosis is essential to finding the best treatment plan.

We offer comprehensive testing, which may include:

• blood tests and other lab studies
• genetic testing, as well as screening of other family members
• nerve conduction tests, such as an electromyogram (or “EMG”), which measures the response of muscles and nerves to electrical activity and is used to help determine the cause of muscle weakness
• magnetic resonance imaging (“MRI”) —  a safe and painless test that uses a magnetic field and radio waves to produce detailed pictures of the body’s organs. It can be used to identify and monitor the muscle changes associated with certain neuromuscular disorders.
• muscle biopsy — a test that's performed to look for cellular abnormalities in muscle tissue. It can be done by cutting a small piece of the muscle or by withdrawing a sample of tissue with a needle and syringe.
  

Experts Working Together as a Team

Neuromuscular disorders in children require a highly coordinated interdisciplinary approach. That means our skilled specialists work together as a team with one simple goal: To optimize your child’s potential.

Depending on your child’s needs, he or she may see a number of different specialists. A neurologist, a pulmonologist, an orthopedist and a cardiologist may be part of your child’s care team. Physical, occupational, speech and respiratory therapists are involved as well. Some locations with expertise in neuromuscular diseases may also have genetic counselors.

If your child is having issues relating to feeding, gastroenterologists (also called “GI doctors”) and nutritionists can offer their expertise. Specialists in pediatric orthotics (bracing) and assistive technology, such as wheelchairs and scooters, are also available to assist with mobility issues and enhance your child’s independence.

With all these different care providers, we understand how hard it can be to manage the many appointments that are so vital to your child’s well-being. That’s why we always do our best to have your child evaluated by several specialists on the same day, each time he or she visits. It’s all part of our commitment to coordinated care, and also to making the lives of our patient-families just a little bit easier. It’s the Nemours promise: To treat your child as we would our own.