Motor Neuron Diseases

Question 1

Define what a Motor Neuron Disease is?

Answer 1

Disorders that cause degeneration of the motor neurons in the spinal cord with or without similar lesions in the lower brainstem motor nuclei and or the betz cells of the motor cortex of the brain and associated long tracts.

Characterized clinically by progressive wasting and weakness of the affected muscles without sensory, cerebellar or mental changes.

Question 2

How do we characterize ALS?

Answer 2

Mixed upper (spasticity, hyperreflexia, babinksi sign) and lower motor neuron (atrophy, fasiculations) signs especially in the same limb.

Question 3

What is the patho Physiology of ALS?

Answer 3

Degeneration of betz cells, lower brainstem nuclei, descending corticospinal tracts, and anterior horns

Question 4

Explain the progression of ALS as far as clinical presentation?

Answer 4

Most commonly presents after age 50
First sign is mild wasting/weakness of hand muscles manifested by impaired dexterity or hand clumsiness
Next the other hand/arm is involved
Weakness atrophy spreads proximally in the arms
Next legs are affected
Next tongue, pharynx and muscles of respiration become weak.
Accompanying symptoms of fasciculations, cramps, drooling and weight loss.

Question 5

What will EMG show for ALS?

Answer 5

Widespread denervation and reinnervation

Question 6

6 important negatives for ALS?

Answer 6

No sensory symptoms
Normal mentation
No extraocular involvement
Bowel/bladder symptoms not prominent
Decubitus rare
Fasciculations are rarely the presenting sign

Question 7

What is progressive bulbar palsy?
5 clinical signs?
How does it progress?

Answer 7

Selective involvement of the motor nuclei of the lower cranial nerves
Dysarthria, dysphagia, dysphasia, drooling and difficulty chewing
Usually always progresses to a generalized condition like ALS

Question 8

What us Spinal muscular atrophy?
Symptoms?
Progression?

Answer 8

Lower motor neuron problems because of degeneration of anterior horn cells
Begins with upper extremity involvement with weakness and atrophy
Can but usually doesn’t progress to ALS

Question 9

what is primary lateral sclerosis?
4 clinical signs?
Progression?

Answer 9

Upper motor neuron deficits (corticospinal)
Weakness, spasticity, hyperreflexia, and babinski sign
Slow progression