Motor Neurone Disease

Question 1

What is MND?

Answer 1

Neurodegenerative disease causing LMN + UMN signs

Question 2

What is the main motor tract?

Answer 2

Corticospinal
UMN from pre central gyrus which has:
Decussation (lateral - 90% fibres)
No decussation (anterior - 10%)

Question 3

Upper Motor neurone
Location?
Muscle tone?
Reflexes?
Babinski sign?
Fasiculations?
Power?

Answer 3

From motor cortex to spinal cord
Increased muscle tone - hypertonia
Hyperreflexia
+ve babinski sign
No fasiculations
Power=
Arms = Flexors > extensors
Legs = Flexors < extensors

Question 4

Lower Motor neurone
Location?
Muscle tone?
Reflexes?
Babinski sign?
Fasiculations?
Power?

Answer 4

Neurones that connect the impulse from the spinal cord to the effector
Hypotonia, flaccid, muscle wasting, muscle atrophy
Decreased/absent reflexes - hyporeflexia
Babinski -ve
Fasciculations (Involuntary muscle twitches)
Generally power is low

Question 5

What is babinski sign?

Answer 5

Run a sharp instrument along lateral border of sole of foot causes extension of big toe (bends up) and fanning of other toes

Question 6

What is the organisation of movement?
from cortex to muscle

Answer 6

1. Idea of movement = association cortexes - pre motor cortex
2. Activation of UMNs in motor cortex
3. Impulse via corticospinal tract
4. Modulation by:
   Cerebellum = fine tuning
   BG = green signal to move
5. Movement and somatosensory info obtained by sensory tracts

Question 7

RF for MND?

Answer 7

male
fHx (SOD 1 Mutation)
Increased age

Question 8

What 2 things do MND never affect?

Answer 8

EYE MUSCLES = MS + MG do
SENSORY FUNCTION AND SPHINCTERS = MS + polyneuropathies do

Question 9

What can MND be classified into?

Answer 9

ALS (Amyotrophic lateral sclerosis) = MC : UMN + LMN
can progress to bulbar palsy
Progressive muscular atrophy (PMA) - LMN only
Primary lateral sclerosis - UMN only

Question 10

Progressive bulbar palsy affects?

Answer 10

CN 9-12
Worst prognosis
Increased chance resp failure

Question 11

Sx of MND?

Answer 11

Mixed UMN + LMN signs
No eye, sensory, cerebellar or parkinsons signs

Question 12

Dx of MND?

Answer 12

Mainly clinical, (from mixed picture)
EMG (electromyography) - shows fibrillation potentials

Question 13

Tx of MND?

Answer 13

MDT management
Riluzole (anti gluatminergic)
Supportive = physio and breathing support if necessary

Question 14

Complication?

Answer 14

Resp failure, aspiration pneumonia, Swallowing failure

Question 15

What is split hand sign?

Answer 15

Disproportionate increased wasting of thenar muscles compared to hypothenar