What are neuromuscular disorders?

Neuromuscular disorders (NMDs) are a broad group of conditions that impair muscle function. This can happen:

• Directly – through disease of the voluntary muscle itself.
• Indirectly – through disease of the peripheral nervous system or neuromuscular junctions.

Conditions affecting the spinal cord or brain are not considered NMDs

NMDs damage the nerves that control voluntary muscles, such as those in the arms and legs. Nerve cells (neurons) normally send signals that allow these muscles to contract.

When neurons become unhealthy or die, the communication between the nervous system and muscles breaks down. As a result, muscles weaken and waste away.

This weakness can cause twitching, cramps, pain, joint problems, and, in some cases, difficulties with heart function or breathing.

Examples of NMD include:

• amyotrophic lateral sclerosis – Motor Neurone Disease
• multiple sclerosis
• myasthenia gravis
• spinal muscular atrophy.

Many NMDs are genetic, which means they run in families, or there may be a gene mutation, for example, in muscle dystrophies. Sometimes, an immune system disorder can cause them, such as myasthenia.

NMDs are rare, affecting around 1 in every 2,400 people. A neuroscience nurse may not meet a patient with NMD in their clinical career.

Symptoms

Patients with Neuromuscular Disorder can have weakness, loss of muscle bulk, muscle twitching, cramping, numbness, tingling and a host of other symptoms.

Problems with the nerve-muscle junction can also cause droopy eyelids, double vision and weakness that worsen with activity. Some NMDs can also cause difficulty with swallowing, and sometimes, breathing.

The symptoms and signs of NMD may include the following:

• muscular weakness
• myotonia
• loss of muscular control
• myoclonus (twitching, spasming, cramping)
• myalgia (muscle pain)
• swallowing difficulties
• breathing difficulties
• fatigue
• changes in facial appearance
• visual disturbances.

Diagnosis

Diagnosis usually involves:

• History-taking – detailed questions on symptoms, onset and progression.
• Medication and social history – some drugs, toxins, or recreational substances can cause or worsen NMD.
• Physical examination – assessing muscle bulk, tone and neurological function.
• Blood tests – including creatine kinase, myoglobin, or antibody testing (for example, for myasthenia gravis)
• Electrodiagnostic tests – such as electromyography (EMG) and nerve conduction studies.
• Genetic testing – as many NMDs are inherited,
• Age consideration – certain NMDs present at specific life stages (for example, Duchenne muscular dystrophy in early childhood; inclusion body myositis in middle age).

Management

While most NMDs have no cure, treatment aims to relieve symptoms, preserve mobility, and prolong life.

Key approaches include:

• Exercise – strengthening unaffected muscles can improve mobility, though benefits vary by condition.
• Healthy lifestyle – to maintain overall fitness and reduce complications.
• Medicinal and surgical interventions – depending on the underlying cause.
• Multidisciplinary support – including physiotherapy, respiratory therapy, occupational therapy, orthotics, wheelchair services, clinical psychology, and specialist nursing.

The GP plays a central role in day-to-day care, supported by specialist input. Changes in a patient’s health should not automatically be attributed to their NMD — other causes must be actively considered.

It is important to remember that any change in the patients’ condition is not always attributed to the NMD and left to await specialist review and intervention.

GPs and the MDT must actively consider clinical presentation outside the progression of the NMD to ensure patients remain in optimal health and can live well with their chronic condition.

A particular challenge for individuals with some NMDs is that the effect of their condition on their day-to-day life can be variable. The impact of myasthenia and muscle fatigability is not always understood, with individuals being met with disbelief that one moment they were able to do something and another that it was not possible.

Psychosocial considerations

The day-to-day impact of NMD can be significant yet not always visible. For example:

• Myasthenia gravis can cause variable, unpredictable weakness.
• Some muscular dystrophies have a major functional impact despite minimal outward signs.

Education is essential so that health care providers, carers and the wider public understand the nature of these conditions and the support needed.

Role of the nurse in NMD care

All nursing staff have important roles and responsibilities when caring for individuals with NMD. These include:

• understanding NMD aetiology
• proactively managing the ongoing physical impact of NMD on individuals’ daily life
• providing psychosocial support to patients and families living with NMD
• reducing morbidity and preventing mortality for individuals with NMD, enabling them to live well
• engaging and coordinating MTD assessment and input.