Motor neurone disease

Question 1

What is motor neurone disease?

Answer 1

untreatable and rapidly progressive neurodegenerative condition

• progressive motor poblems with both UMN and LMN features
• no sensory problems
• focal onset and continuous spread

Question 2

What is the average survival time for motor neurone disease?

Answer 2

3 years

Question 3

What is the genetic inheritance of motor neurone disorder

Answer 3

90% sporadic

10% inherited

Question 4

When does MND usually present and what clinical symptoms and signs should make you think of motor neuron disease?

Answer 4

It rarely presents before 40 years

S/S

• fasciculation
• the absence of sensory signs/symptoms*
• the mixture of lower motor neurone and upper motor neurone signs
• wasting of the small hand muscles/tibialis anterior is common

Other features

• doesn’t affect external ocular muscles
• no cerebellar signs
• abdominal reflexes are usually preserved and sphincter dysfunction if present is a late feature

Question 5

What are the five different types of MDN?

Answer 5

amyotrophic lateral sclerosis,

primary lateral sclerosis,

progressive (or spinal) muscular atrophy,

progressive bulbar palsy

pseudobulbar palsy

Question 6

Amyotrophic lateral sclerosis - is this common? what signs are seen? In familial cases where is the gene responsible located?

Answer 6

50% patients

typically LMN signs in arms and UMN signs in legs

in familial cases the gene responsible lies on chromosome 21 and codes for superoxide dismutase

Question 7

Primary lateral sclerosis - what signs are seen?

Answer 7

UMN signs only

-leg weakness and is found to have a relatively pure spastic parapesis

Question 8

Progressive muscular atrophy:
What signs are seen?
Which muscles are affected?
prognosis?

Answer 8

LMN signs only
affects distal muscles before proximal
carries best prognosis

Question 9

Progressive bulbar palsy

• what is a bulbar palsy?
• what are the signs/symptoms?
• F:M? what age

Answer 9

bulbar palsy is a lower motor neuron lesion of cranial nerve IX, X and XII

• slurring dysarthria
• dysphagia
• F>M (60-80yrs)

Question 10

Psuedobulbar palsy:

-what is a pseudobulbar palsy?

Answer 10

pseudobulbar palsy = upper motor neurone lesion of cranial nerve IX, X and XII

• increased gag/jaw jerk reflex
• spastic tongue
• palatal movement is absent
• spastic speech (monotonous/slurred/high pitch = donald duck)

Question 11

How is MND diagnosed?

• clinically definitive
• clinically probable
• clinically possible

Answer 11

clinically - diagnosis of exclusion (after ix have ruled out other DDx)

Definitive:

• UMN and LMN signs in bulbar region + 2 or more spinal regions
• OR UMN and LMN signs in 3 spinal regions

Probable:
-UMN and LMN in 2 or more spinal regions with some UMN signs rostral to LMN

Possible:

• UMN and LMN in 1 spinal region
• LMN signs and 2 or more spinal regions
• LMN signs are found rostral to UMN signs

Question 12

What UMN signs exist?

Answer 12

• pseudobulbar affect
• moderate weakness
• spasticity
• hyperreflexia
• extensor (up going) plantar reflexes - babinski sign

Question 13

What LMN signs exist?

Answer 13

• severe weakness
• fasciculations
• muscle cramps
• muscle hypotonicity
• muscle atrophy
• hyporeflexia

Question 14

What is the management of MND?

Answer 14

specialist services: key worker, S+L, nutrition, respiratory needs

Riluzole: prevents stimulation of glutamate receptors, used mainly in amyotrophic lateral sclerosis, prolongs life by about 3 months

Respiratory care:
non-invasive ventilation (usually BIPAP) is used at night
studies have shown a survival benefit of around 7 months