6. Peripheral Nerve Disorders

Question 1

Guillian-Barre syndrome: 2 Clinical characteristics?

wt precedes 2/3 of cases?

2 morphological characteristics

Answer 1

Ascending paralysis and loss of deep tendon reflexes.

Flu-like illness or vaccine preceds.

inflammation of peripheral nerves and segmental demyelination

Question 2

wt cell myelinates peripheral axons? structure of myelin?

Answer 2

schwann cells myelinates in segments known as internodes, separated by nodes of Ranvier

Question 3

name for CT surrounding individual nerve fibers? Ct enclosing fascile? CT enclosing entire nerve?

Answer 3

endoneurium - individual fiber perineurium - nerve fascicle epineurium - entire nerve

Question 4

wt happens to diseintegrating myelin in peripheral nerves?

Answer 4

disintegrating myelin engulfed by schwann cells then macrophages

Question 5

after remyelination wt 2 characteristics are seen?

Answer 5

shorter internodes and thinner myelin

Question 6

wt is pathologically seen after repeated segmental demyelination?

Answer 6

onion bulb composed of schwann cell cytoplasm and basement membrane

Question 7

wt is wallerian degeneration? steps?

Answer 7

focal damage to axon 1. axon starts to break down in first 24 hrs 2. affected schwann cells catabolize myelin then engulf axon fragments 3. macrophages phagocytose debris

Question 8

histologic evidence of nerve regeneration?

Answer 8

regenerating clusters ( multiple closely aggregated, thinly myelinated fibers)

Question 9

lab diagnosis of Guillian -Barre syndrome?

Answer 9

elevated protein in CSF

Question 10

condition w symmetric polyneuropathy? cause?

Answer 10

Lepropmatous leprosy. Invasion of scwann cells by m. leprae

Question 11

histo characteristics of Lepromatous leprosy?

Answer 11

inflammatory infiltrate obscures peripheral nerve twigs

Question 12

wt is this

Answer 12

traumat neuroma associated w transection

Question 13

wr does m leprae like to grow on body?

Answer 13

cool areas (ie extremities)

Question 14

cause of tuberculoid leprosy? manifestation? histo characteristics?

Answer 14

cell mediated response to M leprae

nodular granulomatous inflammation of dermis

enlarged peripheral nerves w granulomas

Question 15

Wr dose Varicella-Zoster lay latent? hw does reactivation present? 2 histo appearances?

Answer 15

sensory ganglia of spinal cord and brainstem vesicular skin eruption in dermatomes hemorrhage + intranuclear inclusions

Question 16

peripheral neuropathy in adult onset DM:

morphological characteristics?

most common course?

Answer 16

endoneurial artery thickening and hyalinization

decreased sensation in distal extremities

Question 17

histo of transection?

Answer 17

traumatic neuroma - mass of tangled axons

Question 18

Peripheral nerve disease w endoneurial artery thickening?

Answer 18

DM

Question 19

Neuropathy w loss of deep tendon reflexes?

Answer 19

Guillan Barre

Question 20

neuropathy w symmetric polyneuropathy?

Answer 20

Lepromatous leprosy

Question 21

Neuropathy w nodular granulomatous inflammation?

Answer 21

Tuberculoid leprosy

Question 22

hypertrophic neuropathy w palpable peripheral nerves?

Answer 22

CMT

Question 23

3 genetic mutations causing CMT? wt do they encode?

Answer 23

17p11.2-p12 - myelin protein 22

1 - myelin protein zero

16p