From the Guidelines
Neuromuscular diseases are disorders that affect the peripheral nervous system, which includes the nerves that control voluntary muscles and transmit sensory information from the body to the brain, and are characterized by a broad spectrum of diagnoses with overlapping but distinct phenotypes, as highlighted in a recent study 1. These conditions impair the functioning of muscles due to problems with the nerves that control them, the neuromuscular junction where nerves connect to muscles, or the muscles themselves. Common examples include:
- Muscular dystrophies
- Myasthenia gravis
- Amyotrophic lateral sclerosis (ALS)
- Peripheral neuropathies
- Spinal muscular atrophy The underlying mechanisms typically involve genetic mutations, autoimmune responses, toxic exposures, or metabolic disorders that disrupt normal nerve-muscle communication or muscle function. Symptoms often include muscle weakness, atrophy, twitching, cramps, numbness, and in severe cases, difficulties with breathing and swallowing. The progression and severity vary widely depending on the specific condition, with some being slowly progressive while others advance rapidly. Early diagnosis is crucial as some neuromuscular diseases now have specific treatments that can slow progression or improve symptoms, though many still lack definitive cures and are managed with supportive care to maintain function and quality of life, as discussed in a more recent study on respiratory management of patients with neuromuscular weakness 2. It is essential to prioritize a multidisciplinary approach to care, including pharmacological, psychosocial, and rehabilitative interventions, to improve outcomes and quality of life for patients with neuromuscular diseases, as recommended in a comprehensive review of Duchenne muscular dystrophy management 3, 4.
From the Research
Definition of Neuromuscular Diseases
Neuromuscular diseases are a broadly defined group of disorders that involve injury or dysfunction of peripheral nerves or muscle. The site of injury can be in the cell bodies, axons, Schwann cells, neuromuscular junction, muscle, or any combination of these sites 5.
Key Features of Neuromuscular Diseases
Some key features of neuromuscular diseases include:
- Injury or dysfunction of peripheral nerves or muscle
- Possible sites of injury include cell bodies, axons, Schwann cells, neuromuscular junction, muscle, or any combination of these sites
- Association with central nervous system disease in some cases, such as amyotrophic lateral sclerosis (ALS) 5
- Difficulty in diagnosis due to the multitude of possible sites of injury 5
Types of Neuromuscular Diseases
Some examples of neuromuscular diseases include:
- Motor neuron diseases, such as infantile spinal muscular atrophy and amyotrophic lateral sclerosis (ALS)
- Peripheral neuropathies, such as Charcot-Marie-Tooth disease
- Congenital muscular dystrophies
- Progressive muscular dystrophies
- Steinert myotonic dystrophy (or myotonic dystrophy type 1) 6
Clinical Presentation and Diagnosis
The clinical presentation of neuromuscular diseases can vary, but muscle weakness is a common symptom shared by many conditions 6. Diagnosis can be challenging due to the complexity of the peripheral nervous system and the multitude of possible sites of injury 5. Electromyography can be a useful tool in diagnosing and localizing the site of injury 5.
Epigenetics and Neuromuscular Disorders
Epigenetic changes, such as DNA methylation, have been observed in neuromuscular disorders, including motor neuron diseases and hereditary muscular dystrophies 7. These changes may have potential for diagnostic and prognostic accuracy, and novel epigenetic drugs are being developed to target these conditions 7.
Acute Manifestations of Neuromuscular Disease
Neuromuscular emergencies can be defined as disorders or exacerbation of diseases of the peripheral nervous system that are rapidly progressive and potentially life-threatening 8. These emergencies can affect any level of the peripheral nervous system and may result in severe morbidity and mortality, often due to neuromuscular respiratory failure 8.