Motor Neuron Disease

Question 1

Patient presents with her right foot “catching” and rolling her ankle for past few months. Recently, left foot also catching and some twitching in her calves.

Answer 1

ALS is on your differential… (case presented in class)

Question 2

Patient presents with asymmetric, distal weakness and atrophy, fasciculations, and cramps

Answer 2

Motor nerve disease (NOTE: atrophy is super notable in motor nerve disease; cramp is usually due to a whole muscle firing up)

Question 3

Patient presents with weakness that is fluctuating and fatigue-able (i.e. muscles get weaker with use)

Answer 3

Disease of neuromuscular junction

Think:
Myasthenia Gravis: bulbar, ocular involvement common
Lambert-Eaton Myasthenic Syndrom - Usually proximal and symmetric - bulbar involvement rare.

Question 4

Patient presents with weakness that is fluctuating and fatigue-able (i.e. muscles get weaker with use) and bulbar and ocular involvement

Answer 4

Myasthenia Gravis

Question 5

Patient presents with weakness that is fluctuating and fatigue-able (i.e. muscles get weaker with use) bilaterally in her proximal muscles

Answer 5

Lambert-Eaton Myasthenic Syndrom - Usually proximal and symmetric - bulbar involvement rare.

Question 6

Patient presents with proximal, non-fluctuating, symmetric, painless weakness

Answer 6

Muscle disease

Question 7

What symptoms are associated with upper motor neuron dysfunction?

Answer 7

Hyperreflexia,
Babinksi and Hoffman signs
Increased tone/spasticity
Slowness of movement

Question 8

What symptoms are associated with lower motor dysfunction?

Answer 8

Hyporeflexia,
Atrophy,
Fasciculations
Cramps

Question 9

Diminished reflexes suggest

Answer 9

peripheral nervous system problem:

1. Roots/Plexus/Nerves (VERY decreased)
2. Sensory Nerves only (VERY decreased)
3. Motor nerves only (VERY decreased)
4. NMJ (moderately decreased)
5. Muscle (moderately decreased)

Question 10

Name two diseases of upper motor neurons ONLY

Answer 10

1. Hereditary Spastic Paraparesis (HSP)

2. Primary Lateral Sclerosis (PLS)

Question 11

Name one disease that involves both upper and lower motor neurons.

Answer 11

Amyotrophic Lateral Sclerosis (ALS)

NOTE: It could be confused with a spinal cord compression, but in that case you would expect some sensory complaints

Question 12

What kinds of viruses can cause lower motor neuron disease?

Answer 12

Polio, polio-like enteroviruses, West Nile

Question 13

What are some non-motor manifestations of ALS?

Answer 13

Weight loss, fatigue, pain due to immobility, pseudobulbar affect (emotional lability - so they might cry or laugh really easily, without corresponding changes in how the patient feels), depression affects 10%, cognitive changes resembling FTD in 5% (specifically changes in behavior, mood, and executive function + language problems)

(note that sensory signs are very unusual despite dropout of DRG cells at autopsy and loss of small fibers in skin biopsy)

Question 14

What do you call clinically evident muscle atrophy?

Answer 14

Amyotrophy

Question 15

What percent of ALS is familial?

Answer 15

10

Question 16

How might you distinguish between UMN and LMN dysarthria?

Answer 16

Central (UMN) dysarthria: “spastic dysarthria” - speed is slow (and rhythm is a little off), but articulation is fine

Peripheral (LMN) dysarthria: “nasal dysarthria” - speed (and rhythm) is normal, articulation is poor; palatal weakness –> nasal quality