12th August 2024

Motor neurone disease (MND)

MND refers to a group of diseases which can affect both upper and lower motor neurons. Extrinsic eye muscles are not affected. There are few sensory symptoms and no sensory signs. Median age of onset is 60 years.

The mainstay of therapy is supportive with early involvement of the multidisciplinary team and medications for symptom control. NIV has been shown to improve survival, while riluzole is the only medication currently licensed with prognostic benefit.

Symptom	Management
Dyspnoea	NIV is first line. Further symptomatic relief may be offered by opioids or benzodiazepines.
Muscle spasms	Mexiletine or quinine sulphate are typically offered.
Sialorrhoea	Atropine, hyoscyamine, amitriptyline or glycopyrrolate.
Spasticity	Baclofen or tizanidine.
Emotional lability	Dextromethorphan-quinidine, amitriptyline or SSRIs.

Amyotrophic lateral sclerosis (ALS) or Lou Gehrig’s disease

ALS makes up 50-70% of cases of MND. Onset is spinal in 75% of cases, bulbar in 20% and respiratory in 5%. The most common initial features include asymmetric limb weakness (thenar wasting in the hand with sparing of hypothenar muscles, foot drop), fasciculations, and stiffness leading to gait abnormalities.

Progressive bulbar palsy

This accounts for ~20% of cases and carries the poorest prognosis. Bulbar symptoms (presenting with dysphagia and/or dysarthria) are present, often with higher cognitive involvement.