Neuromuscular Disorders

What are neuro-muscular diseases in children?

By: Michelle G. Sy, MD

Last edited: June 26, 2025

Pediatric neuromuscular diseases include all disorders with onset in childhood where the primary location of pathology is in the peripheral nervous system.

The peripheral nervous system includes all muscles throughout the body and the nerve cells that connect them. Children with neuromuscular diseases have problems with the nerves and muscles that affect how their muscles work. They may affect the nerves that control different kinds of muscles, the muscles themselves, or the way that the nerves and muscles communicate with each other.

What causes pediatric neuromuscular disorders?

Neuromuscular disorders have a variety of causes. Some are inherited, some may be caused by other diseases, or they may be due to an autoimmune reaction where the body’s immune system attacks itself. Some are caused by injuries, including injuries at birth.

These disorders typically cause muscle weakness. They can be stable and unchanging (static) or worsen over time (progressive). Some neuromuscular disorders are present from birth (congenital), while others begin to show symptoms during childhood, adolescence, or even adulthood.

What are the symptoms of neuromuscular disorders

Symptoms depend on which part of the peripheral nervous system is involved. Generally, the unifying symptom is related to muscle weakness. Children and infants may be observed to have delays, late acquisition, arrest or regression in motor functions.

Other symptoms include exercise intolerance, myalgia or muscle pain, fatigable weakness. In more severe cases rhabdomyolysis can occur from rapid damage and injury to muscles, causing a combination of muscle pain, dark urine, and feeling very weak or tired.

Long term manifestations include abnormal or impaired ambulation, joint contractures, skeletal deformities (particularly scoliosis), swallowing difficulties and respiratory failure. Altered sensory perception commonly occurs in neuropathies and can include complaints of numbness, tingling, pins and needles sensation, and decreased perception of touch.

Genetic neuromuscular disorders are frequently associated with significant lifelong morbidities, which are often severely disabling and associated with early death.

Symptoms associated with neuromuscular illnesses

Low muscle tone or weakness of limbs
Walking abnormalities (e.g., toe walking, excessive clumsiness or poor balance)
Joint contracture
Delays or regression in motor development

Muscle weakness in the arms and legs
Loss of reflexes
Twitching, cramps, numbness or aches and pains
Decreased muscle size and lack of muscle tone
Decreased sensation (tingling, numbness)
Problems with movement, loss of balance and the ability to walk
Droopy eyelids
Double vision
Trouble swallowing
Trouble breathing

What are the different types of pediatric neuromuscular disorders?

In pediatrics, the majority of neuromuscular disorders have a genetic basis, either as a de novo or an inherited pathogenic variant in a single gene.

The most commonly encountered genetic pediatric neuromuscular condition is Duchenne muscular dystrophy (DMD), a primary muscle disease with an estimated prevalence of approximately 1:5,000 boys. Other common disorders include spinal muscular atrophy (a neuronopathy affecting the anterior horn cell), myotonic dystrophy (a multi‐systematic disorder with a significant muscle component), and Charcot–Marie–Tooth disease (a disease of the peripheral nerve).

Notable non‐genetic conditions in children include myasthenia gravis, Guillain–Barré syndrome, and inflammatory myopathies such as dermatomyositis.

How are pediatric neuromuscular disorders diagnosed?

Doctors typically start by getting a medical history including developmental milestones, other illnesses the child had before, as well as information about family members with similar or related symptoms. Your doctor will also do a physical exam to evaluate your child’s reflexes and muscle strength.

The extent of testing is usually geared towards investigating the cause and severity of the disease and depends on whether the disorder is considered to be genetic or non-genetic in origin by your doctor.

To evaluate a neuromuscular disorder, your doctor may request for one or a combination of the following:

Blood tests
- To check the muscle and heart enzymes, antibodies, vitamin levels and toxicology screens
Echocardiogram and electrocardiogram tests
- To check for the status of the heart muscle

Nerve conduction velocity (NCV) and electromyography(EMG) studies
- To test the ability of nerves to conduct electricity to muscles and to examine the health of a muscle.
- During an NCV, electrodes are placed on the surface of your child’s skin to measure the speed and strength of nerve pulses traveling through the body
- During an EMG, a small needle is inserted in the muscle.

The nerve conduction velocity (NCV) is performed to evaluate nerve function by determining the speed of impulses traveling through the nerve.

Muscle or nerve biopsy
- To investigate the disease process affecting the muscle or nerve
- A clinician makes a small incision and removes tissue to examine under a microscope. Depending on the condition, different stains are needed to test for biochemical reactions
Imaging tests
- Magnetic resonance imaging (MRI), Computed tomography (CT) or ultrasound (UTZ) can characterize the structure and function of the muscle and rule out other causes of weakness
Lumbar puncture or spinal tap
- To check cerebrospinal fluid
Genetic testing
- To confirm gene mutations

How are neuromuscular disorders treated?

Treatment for neuromuscular disorders depends on the primary cause of weakness and can be specific to each patient’s symptoms. Often, the focus is on reducing your child's symptoms and improving strength and mobility.

Treatments include:

Physical, occupational and speech/swallowing therapy.
- Specific therapies depend on your child’s condition, and activities are designed to improve performance of daily tasks and to prevent complications by remaining active and functional.
Immunosuppressive agents.
- Your child’s doctor may prescribe steroids or immunoglobulin especially in cases of immune or inflammatory causes of weakness. Steroids may also be used to slow down muscle deterioration in some cases of muscular dystrophy.
Medical monitoring.
- Neuromuscular disorders can lead to other conditions such as scoliosis, heart weakness, trouble breathing and difficulty swallowing. Other specialists such as a cardiologist and pulmonologist may be needed to provide expert management.
Nutritional assessments
- Some neuromuscular illnesses can cause problems in swallowing and weight management.
- Macro- and micro-nutrient deficiencies may also cause damage to the nervous system, or cause complications in those with existing neuromuscular disorders.
Physical medicine and rehabilitation.
- Certain types of medical equipment or braces may help a child improve in breathing and mobility.
Clinical trials.
- Many conditions have no definite cure. Research studies continually develop new ways to help improve care. Some have developed ways to lessen symptoms and improve quality and length of survival.

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3. Management of patients with neuromuscular diseases and acute respiratory failure - Scientific Figure on ResearchGate. Available from: https://www.researchgate.net/figure/Neuromuscular-disease-affecting-respiratory-func-tion_tbl2_270275958

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5. Murdoch Children’s Research Institute

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Child Neurology Society, Philippines, Inc.