Neuromuscular Disorders - Find a Clinic and Get Information

The term “neuromuscular disorder” is derived from the words “neuro” (relating to the nerves) and “muscular” (relating to the muscles).

This refers to diseases of:

• Motor neurons: responsible for controlling the muscles
• Peripheral nerve fibers
• Synapses: responsible for transmitting signals

There are an estimated 800 different forms of these muscle diseases, which are generally rare. In most cases, they are severe and significantly limit those affected in their daily lives.

They affect, for example:

• trunk muscles
• the heart muscle, or 
• respiratory muscles

Examples of neuromuscular diseases include:

• ALS (amyotrophic lateral sclerosis): an incurable degenerative disease of the motor nerves characterized by spastic paralysis
• Limb-girdle muscular dystrophies: belong to the group of hereditary muscle disorders
• Polyneuropathies: are diseases of the peripheral nerves (nerves located outside the central nervous system)
• Spinal muscular atrophy: in this condition, motor neurons in the spinal cord degenerate
• Myotonic dystrophies: a hereditary muscle disorder characterized by muscle weakness and stiffness
• Pompe disease: is a glycogen storage disease associated with a deficiency of the enzyme lysosomal acid maltase

SMA is characterized by progressive paralysis of the arm and leg muscles, as well as the muscles involved in swallowing and breathing @ Dr_Microbe /AdobeStock

In everyday language, people often refer to “muscle wasting.” This is because a decrease in muscle mass is the main symptom of most neuromuscular disorders.

It usually occurs alongside muscle weakness. Muscle tissue is replaced by fat and connective tissue.

In some patients, these symptoms are limited to individual muscles. In others, they affect the entire musculature.

Other typical symptoms of muscle disorders include:

• Muscle pain (medically known as myalgia)
• Cramps
• Muscle twitching and
• sensory disturbances

Depending on the form of the disease, the respiratory muscles may be affected. This can lead to breathing difficulties such as shortness of breath. Sometimes the muscles responsible for swallowing are affected, leading to difficulty swallowing.

In addition to the skeletal muscles, the respiratory muscles may also be affected @ ins /AdobeStock

If the heart muscle is affected by these muscle changes, this often results in cardiac arrhythmias.

When infants or toddlers suffer from muscle disorders, this usually manifests as delayed development of motor skills. As a result, they may find it more difficult than children of the same age to grasp objects, crawl, or walk, for example.

Many forms of neuromuscular disorders are hereditary. They are either congenital—meaning they are present at birth—or, in some cases, do not appear until adulthood.

Some neuromuscular disorders are caused by:

• Infections with certain pathogens
• Autoimmune diseases
• Toxins
• Trauma

Metabolic disorders are also a possible cause of muscle diseases. This is the case, for example, with Pompe disease, which is caused by an enzyme deficiency.

Alcohol abuse and diabetes, each accounting for approximately 25 to 30%, are the most common causes of neuromuscular disorders @ Axel Bueckert /AdobeStock

Diagnosing muscle disorders is quite difficult. These conditions are rare, so many doctors have little or no experience with them.

As a result, a muscle disorder is often suspected only at a late stage. Furthermore, there are many different manifestations of the disease, which makes it difficult to narrow down the diagnosis.

The medical history provides initial clues. Here, the doctor looks for characteristic symptoms. If a muscle disorder is strongly suspected, specialized tests are performed:

Neurological electrophysiological methods such as electroneurography (ENG) and electromyography (EMG). An ENG provides information about nerve conduction, while an EMG reveals muscle activity.

A blood test provides important clues. The muscle enzyme creatine kinase accumulates in the blood at higher levels when muscles are damaged. An elevated “CK” level is therefore indicative of muscle damage. However, this elevation can also occur after intense physical exertion.

To get a more accurate picture, the treating physician uses imaging techniques such as ultrasound and MRI. This allows them to examine the muscular structures.

A muscle biopsy is another method that can confirm a suspected muscle disorder. During this procedure, the doctor removes a small tissue sample from the muscle, which is then examined by a laboratory for abnormalities.

Some hereditary muscle diseases can also be diagnosed through specialized genetic testing in a laboratory.

If sleep-related breathing disorders (sleep apnea) are present, a more detailed diagnosis may be conducted in a sleep laboratory.

A muscle biopsy is often necessary for diagnosis @ JK_kyoto /AdobeStock

Since neuromuscular disorders are rare, it makes sense to visit a specialized care center. There, various doctors work together in an interdisciplinary team. 

Specialists in muscle disorders include:

• Neurologists
• Orthopedic surgeons
• Internal medicine physicians
• Pulmonologists, and
• Cardiologists

Symptomatic treatment includes, for example,

• physical therapy
• orthopedic aids
• speech therapy, as well as
• usually a stay at a rehabilitation facility

The specific treatment depends on the severity of the condition and the individual symptoms. In cases of breathing difficulties, respiratory support devices are necessary.

The goal of rehabilitation is to help those affected achieve greater independence and self-determination in their daily lives @ auremar /AdobeStock

Psychological support is also beneficial, as the condition is often very stressful for those affected.

If the heart muscle is under severe strain, heart surgery may be an option. In some cases, a heart transplant may be necessary.

Whether medications are available depends on the type of muscle disease. 

Active ingredients are available for:

• Many forms of myositis (inflammatory muscle disorders) and 
• Endocrine myopathies (hormone-related muscle diseases)

If the disease causes physical limitations, assistive devices are available. If walking is difficult for those affected, walking aids or wheelchairs can be used. 

The German Society for People with Muscle Diseases offers assistance to those affected through an independent assistive device counseling center.

Neuromuscular diseases are generally incurable. It is difficult to make predictions because the symptoms of the various forms of the disease vary greatly.

However, they are usually progressive diseases. Doctors distinguish between rapidly progressive and slowly progressive forms of the disease. These vary from disease to disease.

The goal is to halt or slow the progression of the disease and to maintain or improve quality of life.

In the future, research in the field of gene therapy is expected to yield new therapeutic approaches that provide relief.