Neuromuscular disorders

Definition

Neuromuscular disorders refer to conditions that impact two distinct areas: the nerves that govern the muscles involved in our controlled movements, and the nerves that communicate sensory information back to the brain.

During instances where communication between the nervous system and muscles deteriorate, those nerve cells (neurons) are ailing or dying. Consequently, muscles waste away and lose mass (atrophy). Neuromuscular disorders can either be congenital or acquired over the course of someone’s life.

Within the Shriners Center of Excellence at UF Health, nationally recognized for its performance in pediatric orthopaedic care, children will be diagnosed and treated with the goal of making a positive impact on symptoms, mobility and lifespan.

Adults with neuromuscular disorders are seen at our world-renowned Norman Fixel Institute for Neurological Diseases.

Types

Neuromuscular disorders refer to a broad classification of ailments that come in many forms, all of which lead to muscle weakness and weariness that becomes more pronounced over time. Because of the wide range of characteristics among neuromuscular disorders, it’s important for patients to be treated by a team that holds experience in multiple disciplines.

There are four main groups of neuromuscular disorders:

  • Motor neuron diseases – The lower and sometimes upper motor neurons gradually die in this type of condition. The most common form of this is amyotrophic lateral sclerosis (ALS), or Lou Gehrig’s disease.
  • Neuropathies – Nerves not located within the spinal cord (the peripheral nervous system) are affected in this group of disorders. Charcot-Marie-Tooth disease is one example of these.
  • Neuromuscular junction disorders – The nerve impulse normally transmitted to a muscle to facilitate movement or contraction for the muscle is blocked. The most common of these is myasthenia gravis.
  • Myopathies – Some myopathies, or diseases of the muscles, can be a byproduct of a rare side effect of autoimmune diseases, hormonal disorders or even medications.
  • Muscular dystrophies – Also known as muscle wastage, this can be caused by genetic mutations that don’t allow muscle tissue to be maintained or repaired.
  • Metabolic diseases of the muscle – This group of disorders involves errors in metabolism as it pertains to producing energy in muscle cells.

These are specific types of neuromuscular disorders:

Causes and risk factors

Many neuromuscular disorders are genetic, either being inherited at birth from family or being produced from a spontaneous gene mutation. In some cases, immune system disorders can cause these conditions.

However, the exact causes vary by condition. For instance, while diseases such as muscular dystrophy and Charcot-Marie-Tooth are commonly traced back to genetic factors, multiple sclerosis is an autoimmune disorder but arises from genetic or environmental factors, as well as infectious agents like viruses.

Symptoms

Indications of a neuromuscular disorder can potentially be revealed at any stage of a person’s life. Symptoms can become evident in infancy, while others may emerge in childhood or even adulthood.

Symptoms vary depending on the condition and can range from mild, moderate or life threatening. These are just a few symptoms related to neuromuscular disorders:

• Muscle loss
• Muscle weakness (can result in cramps, aches and pains)
• Movement/balance problems
• Numbness, tingling or other painful sensations
• Drooping eyelids
• Double vision
• Breathing difficulties
• Swallowing difficulties

Diagnosis and treatment

Numerous tests can help diagnose a neuromuscular disorder.

Blood tests can assess unusual levels of chemicals and antigens in the blood frequently found in specific neuromuscular diseases. An electromyography (EMG) can assess the health of a muscle. Nerve conduction studies measure the ability of nerves to conduct electricity. Muscle biopsies and genetic testing can also be performed.

Most neuromuscular disorders have no cure, and the goal of treatment is to improve symptoms, increase mobility and lengthen life.

Outlook (Prognosis)

With the objective being to relieve symptoms and prolong life, some conditions can be treated more effectively than others.

Review Date
02/05/2020

Reviewed By
Dr. Laurel Blakemore, MD, Division Chief, Pediatric Orthopaedics.