Anterior Horn Cell Disease (Motor Neuron Disease)

Question 1

What is Motor Neuron Disease?

Answer 1

Disorders that cause degeneration of the motor neurons (anterior horn cells) in the SC with/without similar lesions in the lower brainstem motor nuclei and/or the Betz cells of the brain an_d associated long tracts._

Question 2

What are the characteristics of Motor Neuron Disease?

Answer 2

1. Progressive muscle atrophy/wasting
2. Weakness of affected muscles
3. NO sensory, cerebellar, or mental changes.

Question 3

Name the main types of idiopathic Adult Motor Neuron Disease

Which is the MC

Answer 3

1. Amylotrophic Lateral Sclerosis (2/3 of cases ) = MC
2. Progressive Bulbar Palsy (1/3 of cases)
3. Progressive (spinal) Muscular Atrophy
4. Primary Lateral Sclerosis

Question 4

Signs/sx’s seen with ALS

Answer 4

1. UMN signs (spasticity, hyperreflexia, Babinski sign) = loss of corticospinal tract
2. LMN signs (atrophy, fasciculations) = loss of anterior horn cells
3. Can have bulbar involvement of UMN/LMN

Question 5

What are the sensory symptoms are seen with ALS?

Answer 5

NONE

Question 6

The pathophysiology of ALS is due to degeneration of which 4 things?

Answer 6

1. Betz cell
2. Lower brainstem nuclei
3. Descending corticospinal tracts
4. Anterior horn cells

Question 7

What will an EMG of pt with ALS show?

Answer 7

Widespread denervation and reinnervation

Question 8

Clinical presentation of ALS

Answer 8

1. Occurs 20-60YO, MC after 50YO in Males
2. First sign = hand clumisiness or impaired dexterity due to mild wasting/weakness of hands
   
   1. Eventually, other hand becomes affected
3. Weakness and atrophy spreads proximally in both arms
4. Next, legs are affected
5. Next, atrophic weakness spreads to tongue, pharynx, and respiratory muscles.
6. + fasiculations, cramps, droopling and WL

Question 9

ALS: What do you see on

1. CPK
2. CSF
3. Imaging studies of brain and spine
4. HIV
5. Muscle biopsy

Answer 9

1. CPK = NL or slightly ↑
2. CSF = NL
3. Imaging studies of brain and spine = NL
4. HIV
5. Muscle biopsy only needed in confusing cases

Question 10

What are important rules of thumbs in ALS?

Answer 10

1. NL mentation
2. NO sensory sx
3. NO EOM involvement
4. Bowel and bladder sx are not prominent
5. Fasciculations are rarely the presenting symptoms

Question 11

What is the course and prognosis of ALS?

Answer 11

1. Progressive disease: no remissions, relapses or stable plateu.
2. Symptoms last for 4 years (27- 43 months)
3. Death = respiratory failure, pneumonia (aspiration) or PE within 2-5 years

Question 12

Treatment for ALS

Answer 12

1. Supportive: feeding tube, ventilation, symptomatic meds
2. Riluzol (glutatmate inhibitor) = prolongs life for 3 - 6 months.

Question 13

What is Progressive Bulbar Palsy?

Answer 13

Degeneration of motor nuclei of the lower CN =>

• 1. Dysarthria
• 2. Dysphagia
• 3. Dysphonia
• 4. Drooling
• 4. chewing/respiratory Difficulty

Question 14

What is the course of Progressive Bulbar Palsy?

Answer 14

Rarely is an isolated syndrome; it almost ALWAYS progresses to generalized ALS.

Question 15

Which deficits predominate in Progressive Spinal Muscular Atrophy (SMA); mean age of onset and MC in who??

Answer 15

• Mean age = 64 y/o Males
• Degeneration of ONLY anterior horn cells => LMN deficits predominate
• NO UMN involvement

Question 16

Typical presenting sx’s of Progressive Spinal Muscular Atrophy?

Answer 16

• Often begins with symmetric upper extremity involvement
• Weakness + atrophy + respiratory difficulty

Question 17

Prognosis of Progressive Spinal Muscular Atrophy?

Answer 17

Survival rate ≥15 years (better w/ earlier age of onset)

Question 18

Which deficits prevail in Primary Lateral Sclerosis; what are the signs/sx’s?

Answer 18

UMN (corticospinal) deficits prevail

1. Weakness
2. Spasticity
3. Hyperreflexia
4. Babinski signs

Question 19

Progression and survival rate like for Primary Lateral Sclerosis

Answer 19

• - Slow progression, but can evolve into ALS
• • Survival rate better than ALS

Question 20

What is an acquired adult Motor Neuron Disease?

Answer 20

Post-Polio Syndrome