Motor neuron disease

Question 1

What is MND

Answer 1

Neurodegenerative diseases caused by selective loss of neurons in motor cortex/cranial nerve nuclei/anterior horn cells

Question 2

What are types of MND?

Answer 2

ALS

Progressive bulbar palsy

Progressive muscular atrophy

Primary lateral sclerosis

Question 3

What is ALS

Answer 3

Loss of motor neurons in motor cortex and the anterior horn of the cord, so combined UMN+ LMN signs. Worse prognosis if: bulbar onset, ↑age; ↓FVC

Question 4

What is progressive bulbar palsy

Answer 4

Affects CN 9-12

Question 5

What is progressive muscular atrophy

Answer 5

Anterior horn cell lesion, so LMN signs only. Affects distal muscle groups before proximal. Better prognosis than ALS

Question 6

What is primary lateral sclerosis

Answer 6

Loss of Betz cells in motor cortex: mainly UMN signs, marked spastic leg weakness and pseudobulbar palsy. No cognitive decline.

Question 7

What are Sx of MND

Answer 7

Usually > 40
	• Stumbling spastic gait
	• Foot-drop ± proximal myopathy
	• Weak grip (door-handles don’t turn)
	• Weak shoulder abduction (hair-washing is hard)
Aspiration pneumonia

UMN and LMN signs

Fasciculations

Frontotemporal dementia