Motor Neurone Disease

Question 1

Definition of MND

Answer 1

Progressive neurodegenerative disorder of the cortical, brainstem and spinal motor neurones (upper and lower)

Question 2

Most common form of MND

Answer 2

The most common form of MND is Amytrophic Lateral Sclerosis (ALS): presents as a combination of upper and lower motor neurone symptoms

Question 3

Pathophysiology of MND

Answer 3

• Mechanism of disease is UNKNOWN
◦ However, glutamate toxicity, oxidative stress, protein misfolding and microglial activation are some theories
• There would be motor cell death, followed by retrograde atonal degeneration and then subsequent denervation and reinnervation in muscles

Question 4

History and Examination of MND

Answer 4

• Upper extremity weakness: can be due to UMN or LMN loss
• Stiffness, with poor co-ordination and balance: may be due to UMN
• Speech disturbances: may be slurred, nasal, slow or strained
• Dysphagia
• Emotional incontinence: inappropriate bursts of crying or laughing
• May have dyspnoea due to respiratory muscles being affected

UMN signs:
‣ Spasticity (increased tone of limbs and tongue)
‣ Brisk limbs and jaw reflexes (Hyperreflexia)
‣ Babinski’s sign
‣ Loss of dexterity
‣ Dysarthria
‣ Dysphagia
LMN signs:
‣ Weakness
‣ Muscle wasting/atrophy
‣ Tongue fasiculations/wasting
‣ Nasal speech
‣ Dysphagia

Question 5

Sensory examination results in MND?

Answer 5

• Sensory examination should be normal

Question 6

Risk factors for MND

Answer 6

‣ Genetic predisposition
‣ Age >40

Question 7

Treatment for MND

Answer 7

1) Riluzole + Supportive care: Riluzole can prolong the survival of patients. Supportive care such as counselling regarding end-of-life issues
+ manage other symptoms

Question 8

Prevention and prognosis of MND:

Answer 8

The risk of aspiration pneumonia is high in these patients, therefore take precautions to reduce the risk of this. May need a PEG tube

Follows a progressive course with intervals of remissions, relapses or stabilisation. But would ultimately lead to disability and death
Survival rates are around 3-5 years

Question 9

Complications of MND

Answer 9

• Respiratory failure: Early symptoms affecting the intercostal muscles can be treated with NIV, however, the condition will continue to deteriorate