Motor Neurone Disease

Question 1

What is motor neurone disease?

Answer 1

-Disease of motor neurones
=LMN in spinal cord
=LMN in brain stem
=UMN in cerebral cortex

-Neurodegenerative pathology

Question 2

Describe the neurodegenerative pathology of MND

Answer 2

-Degeneration of neurons
-Associated with inclusion bodies
-Containing misfolded proteins

Question 3

Describe prognosis of MND

Answer 3

-Cause unknown (5-15% genetic)

-Progressive, fatal, currently incurable
=Progressive weakness: immobility, loss of speech, dysphagia, dyspnoea

-ALS: 2-5 years, PBP: 6 months-3 years
-50% die within 3 years

Question 4

Prevalence of MND

Answer 4

-Uncommon below 40
-Mean age of onset 50-60 (increasing incidence with age)
-x6 more common in 70s than 50s
-2/100,000

Question 5

Clinical manifestations of MND

Answer 5

-Weakness
-Generally of voluntary musculature: limbs, speech, swallowing, breathing
-Tends to spare eye movements, bladder, bowels

-LMN + UMN limbs and bulbar/ LMN limbs/ LMN, UMN bulbar

-Asymmetrical limb weakness
-Dysarthria
-Tongue fasciculations
-Weakness of foot and ankle and dorsiflexion
-Reduced grip strength
-Difficulty swallowing and choking on food
-Present after 40
-Wasting of the small hand muscles/ tibialis anterior
-Absence of sensory signs
-Does not affect external ocular muscles
-No cerebellar signs
-Spastic
-Unsteady gait
-Painful muscle spasms
-Foot and head drop
-Fronto-temperoal dementia

Question 6

Features of LMN disease

Answer 6

-Wasting
-Fasciculation

Question 7

Features of UMN disease

Answer 7

-Spasticity
-Brisk TR
-Extensor Plantar Response

Question 8

Various clinical terms for MND

Answer 8

-ALS (amyotrophic lateral sclerosis)
-Progressive muscular atrophy (LMN only, distal>proximal)
-Progressive bulbar palsy

Question 9

Diagnosis of MND

Answer 9

-Clinical: progressive LMN/UMN signs, no other signs in general (no sensory deficit)
-Supporting evidence: EMG, NCS (nerve conduction studies)

-Normal motor conduction
-Electromyography= reduced number of action potentials with increased amplitude (ongoing, chronic denervation)
-MRI to exclude cervical cord compression and myelopathy

Question 10

MND management

Answer 10

-Aids for mobility/ limb use
-Swallowing management
-Communication management
-Breathing support
-Emotional support
-Riluzole (prevents stimulation of glutamate receptors, amyotrophic lateral sclerosis)
-BIPAP
-PEG tube