B7.013 Neuropathy Cases

Question 1

traumatic neuropathy

Answer 1

acute mechanical compression of the nerve
duration and magnitude of force determines severity of injury:
-neuropraxic
-axonotmetic
-neurotmetic

Question 2

treatment for Saturday night palsy

Answer 2

watchful waiting

resolution in about 3 wks

Question 3

common cause of superficial radial neuropathy

Answer 3

handcuffs!

due to constriction of radial nerve at wrist

Question 4

most common causes of focal neuropathies of the extremities

Answer 4

trauma

entrapment

Question 5

entrapment neuropathy

Answer 5

mechanical compression of a nerve in a narrowed anatomic compartment
dysfunction related to a combo of:
-nerve ischemia
-focal demyelination
-axonal crush injury

Question 6

what is the carpal tunnel

Answer 6

carpal bones form the floor and walls
roof is created by the transverse carpal ligament
nine flexor tendons with their sheaths accompany the median nerve through the tunnel

Question 7

what is carpal tunnel syndrome

Answer 7

median nerve entrapment at the wrist

nerve dysfunction secondary to chronic mechanical compression

Question 8

carpal tunnel syndrome symptoms

Answer 8

intermittent pain, numbness tingling in the fingers - 90%
subjective weakness of hand grip - 75%
initially at night only and may wake the patient from sleep - 85%
provoked by hyperextension or hyperflexion - 70%
pain can radiate up into forearm or shoulder - 40%
subjective hand swelling and stiffness - 35%

Question 9

carpal tunnel syndrome signs

Answer 9

discrete sensory disturbance in the 1st 3 fingers
weakness or atrophy of the thenar muscles
NCS likely confirm the diagnosis but can be normal 15% of the time

Question 10

potential histo abnormalities in entrapment neuropathies

Answer 10

normal
myelin changes
-paranodal myelin retractions
-bulbous paranodal swellings
-segmental demyelination
axonal changes
-variable degrees of axonal degeneration and regeneration
increase in endoneurial and perineurial connective tissue

Question 11

epidemiology of carpal tunnel syndrome

Answer 11

prevalence 125 per 100,000
incidence 1.2 per 10,000 person years
peaks at age 55-64
female: male 2:8

Question 12

causes of carpal tunnel syndrome

Answer 12

repetitive hand and wrist movement, seen in a variety of activities and occupations
increased pressure within the carpal tunnel due to certain positions of the hand and wrist and edema of the flexor tendons

Question 13

conservative management of carpal tunnel syndrome

Answer 13

use of a resting wrist splint and advice to reduce provoking activities (successful in 50%)
steroid injections (immediate, but not sustainable)
systemic steroids (not good long term)

Question 14

surgical release of carpal tunnel syndrome

Answer 14

improvement rate of 80-90%

usually return to work in 2-3 weeks

Question 15

one way to distinguish root vs. nerve injury

Answer 15

sensory nerve APs are normal in radiculopathies
BUTTT
EMG of paraspinal muscles can be abnormal in radiculopathies due to branches of the dorsal ramus

Question 16

common causes of radiculopathy

Answer 16

degenerative changes of the vertebrae

disc herniation

Question 17

how to test nerve vs. root

Answer 17

find a muscle the root innervates that the nerve doesn’t and test it

Question 18

cause of decreased sensation on lateral thigh

Answer 18

entrapment of lateral femoral cutaneous beneath inguinal ligament

Question 19

ways to entrap the lateral femoral cutaneous

Answer 19

weight gain
tight belts
tool belts

Question 20

EMG and NCV findings in distal symmetric peripheral neuropathy

Answer 20

decreased amplitudes or absent SNAPs in the feet (sural) with relative normal latencies (an axon problem, not a myelin problem)
CMAPs may be normal or show decreased amplitude

Question 21

spinal tap findings in AIDP

Answer 21

elevated spinal fluid protein without pleocytosis (no increase in WBCs)

Question 22

EMG findings in AIDP

Answer 22

initially normal except for prolonged F waves

Question 23

pattern of numbness on ears, forehead, nose, toes, and fingers

Answer 23

cold dependent pattern

Question 24

what conditions has a cool dependent pattern of involvement

Answer 24

leprosy

bacteria thrives in cool portions of body