Summary

Motor neurone disease (MND), known as amyotrophic lateral sclerosis (ALS) in the US, is a progressive neurodegenerative disorder characterised by degeneration of upper and lower motor neurons. It causes progressive weakness, muscle wasting, and eventually respiratory failure. Crucially, it spares sensory and autonomic function. There is no cure, but riluzole modestly extends survival, and multidisciplinary care significantly improves quality of life. Median survival from symptom onset is 2-4 years, though 10% survive beyond 10 years.

Key Facts

• Definition: Progressive degeneration of upper (UMN) and lower (LMN) motor neurons
• Incidence: 2-3 per 100,000 per year; lifetime risk 1 in 300
• Peak Age: 55-75 years; rare <40 years
• UMN Signs: Spasticity, hyperreflexia, Babinski sign
• LMN Signs: Wasting, fasciculations, weakness, hyporeflexia
• Key Sparing: Sensory intact, eye movements spared, sphincter control preserved
• Treatment: Riluzole (modest survival benefit), MDT care

Clinical Pearls

"Weakness Without Sensory Loss": The hallmark of MND is progressive weakness WITHOUT sensory involvement. If there is significant sensory loss, think of alternative diagnoses (e.g., peripheral neuropathy, myelopathy).

"Split Hand Sign": Thenar muscle (APB) is more wasted than hypothenar muscles in MND. This helps differentiate from other causes of hand wasting.

Eye Movements and Sphincters Spared: Even in advanced disease, patients retain eye movement (can use eye-gaze technology) and continence. If these are affected, reconsider the diagnosis.

Why This Matters Clinically

MND is a devastating diagnosis with major implications for patients and families. Early diagnosis allows timely intervention (riluzole, NIV, PEG), advance care planning, and access to specialist MDT services. Recognition of the characteristic pattern of mixed UMN and LMN signs without sensory involvement is crucial.

Structured Approach

General:

• Nutritional status (weight loss common)
• Respiratory assessment (count to 20 in one breath)
• Affect (pseudobulbar affect)

Motor Examination:

• Bulk: Wasting pattern, split hand sign
• Tone: Spasticity (UMN) vs flaccidity (LMN)
• Power: MRC grading, pattern of weakness
• Reflexes: Increased (UMN) vs decreased (LMN)
• Fasciculations: Observe muscles at rest

Cranial Nerves:

• Tongue: Wasting, fasciculations, strength
• Jaw jerk: Brisk (UMN bulbar)
• Speech: Dysarthria
• Swallow: Wet voice, cough strength

Special Tests

Natural History

MND is a progressive, ultimately fatal disease. Median survival from symptom onset is 2-4 years. Death is usually from respiratory failure or aspiration pneumonia. However, survival varies significantly based on phenotype and care.

Outcomes

Prognostic Factors

Poor Prognosis:

• Bulbar onset
• Older age at onset
• Rapid progression
• FTD features
• Low FVC at diagnosis
• Malnutrition

Better Prognosis:

• Limb onset
• Younger age (<40)
• Slow progression
• PLS phenotype
• MDT care access

Impact of Care:

• MDT care: Improves survival by 6-12 months
• NIV: Extends survival by several months and improves QoL
• Riluzole: ~3 months survival benefit

Key Guidelines

1. NICE NG42: Motor Neurone Disease (2016, updated 2019) — Comprehensive UK guidance on diagnosis, referral, MDT care, respiratory management, and end-of-life care.

2. European ALS Consortium Guidelines (EFNS/EAN) — Diagnostic criteria and management recommendations.

Landmark Trials

Bensimon et al. (1994) — Riluzole trial

• First RCT showing survival benefit in ALS
• Key finding: ~3 months survival extension
• Clinical Impact: Established riluzole as standard-of-care

Bourke et al. (2006) — NIV trial

• RCT of NIV in MND with respiratory impairment
• Key finding: NIV improves survival (especially non-bulbar) and QoL
• Clinical Impact: Established early NIV as essential intervention

Evidence Strength

What is Motor Neurone Disease?

Motor neurone disease (MND), also called ALS, is a condition where the nerve cells (motor neurons) that control your muscles gradually stop working. This causes muscles to weaken and waste away over time. Importantly, it doesn't affect your senses (sight, hearing, touch), bladder or bowel control, or your ability to think clearly in most cases.

Why does it matter?

MND is a serious condition that gets worse over time. There is currently no cure, but there are many things that can help:

• Medication can slow the disease slightly
• Breathing support and feeding tubes can extend life
• Care from a specialist team significantly improves quality of life
• Symptoms like stiffness, drooling, and pain can be well-managed

How is it treated?

1. Medication (Riluzole): This slows the disease slightly and is taken as tablets twice daily.

2. Specialist care team: You'll be seen by a team including neurologists, physiotherapists, speech therapists, dietitians, and palliative care specialists.

3. Breathing support: If breathing muscles weaken, a mask worn at night (NIV) can help you breathe and improve sleep.

4. Nutrition: If swallowing becomes difficult, a feeding tube (PEG) can help you get enough nutrition.

5. Communication aids: As speech becomes difficult, devices from simple boards to eye-gaze computers can help you communicate.

What to expect

• The disease progresses at different rates for different people
• Average survival is 2-4 years, but some people live much longer
• Specialist care can significantly improve quality of life
• Planning ahead for the future is an important part of care

When to seek help

Contact your team urgently if:

• You develop breathing difficulties, especially lying down
• You're unable to swallow safely or are choking
• You're losing weight rapidly
• You develop a chest infection