Neuropathy, Myopathy & Motor Neuron Disease

Question 1

What is the difference between a mononeuropathy and a polyneuropathy?

Answer 1

Mononeuropathy affects a single, major nerve, typically caused by trauma or compression
Polyneuropathy affects multiple small peripheral nerves caused by demyelination or axonal degeneration

Question 2

What is carpal tunnel syndrome?

Answer 2

Median mononeuropathy at the wrist
Inflamed flexor tendons compress the median nerve within the carpal tunnel
Corrected surgically

Question 3

What is Wallerian degeneration?

Answer 3

Myelin and axonal degeneration distal to a severe nerve injury

Question 4

What are some symptoms characteristic of a polyneuropathy?

Answer 4

Early sensory loss/impairment in distal limbs
Tingling, pins & needles
Distal limb weakness & atrophy
Loss/decreased reflexes

Question 5

How do EMG testing results differ between a demyelination problem compared to an axonal problem?

Answer 5

Slowed conduction velocity suggests demyelination

Loss of amplitude suggests axonal loss

Question 6

What is Guillain-Barre syndrome?

Answer 6

Acute polyneuropathy causing ascending areflexic paralysis. 50% of patients had a recent viral respiratory infection.

Causes inflammation and demyelination of peripheral nerve roots

Good prognosis

Question 7

What are some of the causes of chronic acquired polyneuropathies?

Answer 7

Diabetes mellitus
Hypothyroid
Rheumatoid arthritis
Lupus
Cancer

Question 8

What is myopathy?

Answer 8

A primary disease of muscle presents with weakness, fatigue, cramps.
Proximal limb weakness and atrophy with late loss of reflexes
Intact sensation

Question 9

What is polymyositis?

Answer 9

Inflammation and weakness of multiple muscles from viral infections or drug reactions. In US, usually autoimmune.
Treated with corticosteroids or other immunosuppressive drugs.

Question 10

What is Duchenne’s muscular dystrophy?

Answer 10

X-linked disorder in which dystrophin is absent
Presents as proximal weakness in boys
Cardiorespiratory death by 30s

Question 11

What is spinal muscular atrophy?

Answer 11

Anterior horn cells affected by motor neuron disease.

Presents with LMN signs of weakness, atrophy, areflexia and fasciculations.

Question 12

What is Werdnig-Hoffman?

Answer 12

Infantile-onset spinal muscular atrophy
Terminal condition with rapid developing diffuse weakness
No curative treatment available

Question 13

What disease has the worst prognosis of all motor neuron diseases?

Answer 13

ALS

50% die within 3 years from respiratory failure or complications of profound weakness

Question 14

What spinal tract is affected by ALS?

Answer 14

The CST is affected bilaterally in ALS