Peripheral nerve injuries and palsies

Question 1

Give 6 examples of peripheral nerve injury conditions:

Answer 1

1) brachial plexus injury
2) peroneal foot drop
3) spinal accessory nerve injury
4) carpal tunnel syndrome
5) Charcot-Marie-Tooth Disease
6) Guillain-Barre syndrome

Question 2

Give the ABCDE non-traumatic causes of peripheral neuropathy:

Answer 2

1) alcohol
2) B12 deficiency
3) cancer (myeloma) and CKD
4) diabetes and drugs
5) every vasculitis

Question 3

Name 4 drugs that cause peripheral neuropathy:

Answer 3

1) isoniazid
2) amiodarone
3) leftunomide
4) cisplatin

Question 4

Give 5 general symptoms of peripheral nerve injuries:

Answer 4

1) severe burning, pain
2) muscle weakness
3) reduced reflexes
4) reduced sensation/ paraethesia
5) muscle wasting

Question 5

What is the same of the classification system for peripheral nerve injury?

Answer 5

Sunderland Classification System

Question 6

Describe a first degree peripheral nerve injury:

Answer 6

a reversible conduction block at the site of injury (neuropraxia)

Question 7

Describe second degree peripheral nerve injury:

Answer 7

the loss of the continuity of the axon and its covering myelin but preservation of the connection of the nerve (axonotmesis)

Question 8

Describe third degree peripheral nerve injury:

Answer 8

damage to the axon and their supporting structures

Question 9

Describe fourth degree peripheral nerve injury:

Answer 9

damage to the axons and the surrounding tissues sufficient to create scarring that prevents nerve regeneration

Question 10

Describe fifth degree peripheral nerve injury:

Answer 10

complete transection of the next including the epineurium (neurotmesis)

Question 11

What two muscles does the spinal accessory nerve innervate?

Answer 11

1) sternocleidomastoid
2) trapezius

Question 12

Give two causes of spinal accessory nerve injury:

Answer 12

1) severing during neck surgery
2) trauma

Question 13

Give 3 presentations associated with spinal accessory nerve injury:

Answer 13

1) shoulder pain
2) winging of the scapulae
3) weakness and atrophy of the trapezius muscle

Question 14

Where is the carpal tunnel found?

Answer 14

between the carpal bones and flexor retinaculum in the wrist

Question 15

What is carpal tunnel syndrome?

Answer 15

compression, swelling or narrowing of the carpal tunnel, compressing the median nerve

Question 16

What structures pass through the carpal tunnel?

Answer 16

1) median nerve
2) flexor tendons

Question 17

What is the motor function of the median nerve in the hand?

Answer 17

innervation to the thenar eminence

Question 18

What three muscles make up the the thenar eminence?

Answer 18

1) abductor pollicis brevis
2) opponens pollicis
3) flexor pollicis brevis

Question 19

What is the sensory function of the median nerve in the hand?

Answer 19

sensory innervation to the thumb, index and middle finger and lateral half of the ring finger

Question 20

Give 7 risk factors for carpal tunnel syndrome:

Answer 20

1) acromegaly
2) rheumatoid arthritis
3) diabetes
4) hypothyroidism
5) repetitive strain
6) obesity
7) perimenopause

Question 21

Are carpal tunnel syndrome symptoms worse in the day or night?

Answer 21

Night

Question 22

Give 5 symptoms of carpal tunnel syndrome:

Answer 22

1) weakness of thumb movement and grip strength
2) wasting of the thenar muscles
3) numbness in distribution of the median nerve supply
4) burning sensations
5) paraesthesia (pins and needles)

Question 23

Name the 2 special tests for carpal tunnel syndrome:

Answer 23

1) Phalen’s test
2) Tinel’s test

Question 24

Describe Phalen’s test for carpal tunnel syndrome along with the positive result:

Answer 24

have the patient put the backs of their hands together with their wrists at 90 degrees - a positive result is numbness and paraesthesia in this position

Question 25

Describe Tinel's test for carpal tunnel syndrome along with the positive result:

Answer 25

tapping the wrist in the location where the median nerve travels through the carpal tunnel - the positive result is numbness and paraesthesia during this

Question 26

What investigation is used to diagnose carpal tunnel syndrome?

Answer 26

nerve conduction studies

Question 27

Describe the nerve conduction studies used to test for carpal tunnel syndrome:

Answer 27

where a small electrical current is applied by an electrode to the median nerve - recording electrodes over the median nerve record the current that reaches them

Question 28

Give 3 treatment options for carpal tunnel syndrome:

Answer 28

1) wrist splints 2) steroid injections 3) surgery

Question 29

Describe carpal tunnel syndrome surgery:

Answer 29

under local anaesthetic, the flexor retinaculum is cut to release the pressure on the median nerve

Question 30

What structure is injured in Erb's palsy?

Answer 30

the superior trunk of the brachial plexus (C5/C6)

Question 31

What is the most common cause of Erb's palsy?

Answer 31

difficult childbirth (damage to neonate's neck)

Question 32

What mechanism causes Erb's palsy (damage to the superior trunk of the brachial plexus)?

Answer 32

excessive lateral neck flexion

Question 33

What 4 nerves are affected by Erb's palsy?

Answer 33

1) musculocutaneous nerve 2) axillary nerve 3) suprascapular nerve 4) nerve to subclavius

Question 34

Give three areas where sensation is lost in Erb's palsy:

Answer 34

1) sergeant's patch 2) lateral arm 3) lateral forearm

Question 35

Give 4 muscles/ muscle groups that waste in Erb's palsy:

Answer 35

1) deltoid 2) supraspinatus 3) infraspinatus 4) anterior compartment of the arm

Question 36

Give 4 movements that are difficult in Erb's palsy:

Answer 36

1) shoulder abduction 2) shoulder external rotation 3) elbow flexion 4) forearm/ wrist supination

Question 37

What structure is injured in Klumpke's palsy?

Answer 37

inferior trunk of the brachial plexus (C8/T1)

Question 38

What mechanism causes Klumpke's palsy?

Answer 38

excessive force placed on an abducted shoulder

Question 39

What two nerves are injured in Klumpke's palsy?

Answer 39

1) median 2) ulnar

Question 40

Give 4 areas that lose sensation in Klumpke's palsy:

Answer 40

1) median distribution to the hand 2) ulnar distribution to the hand 3) medial forearm 4) medial arm

Question 41

Give 5 movements that are lost in Klumpke's palsy:

Answer 41

1) metacarpophalangeal flexion 2) interphalangeal extension 3) finger abduction 4) finger adduction 5) opposition of the thumb

Question 42

What structure is injured in Horner's syndrome?

Answer 42

T1 nerve root and sympathetic chain

Question 43

Give the 4 characteristic features of Horner's syndrome:

Answer 43

1) ptosis (drooping eye lid) 2) anhidrosis (loss of sweating on the affected side of the face) 3) enophthalmos (eye appears sunken) 4) miosis (constricted pupil)

Question 44

What is Charcot-Marie-Tooth Disease?

Answer 44

an autosomal dominant inherited disease that affects peripheral nerves by causing myelin or axon dysfunction

Question 45

Give 4 classical features of Charcot-Marie-Tooth Disease:

Answer 45

1) pes cavus (high foot arch) 2) distal muscle wasting (causing inverted champagne bottle legs) 3) reduced reflexes 4) limb weakness and reduced muscle tone

Question 46

What is the name of the acute paralytic polyneuropathy characterised by ascending weakness following infection?

Answer 46

Guillain-Barre Syndrome

Question 47

Give 3 infective triggers of Guillain-Barre Syndrome:

Answer 47

1) Campylobacter jejuni 2) Ctyomegalovirus 3) Epstein-Barr virus

Question 48

Describe the pathogenesis of Guillain-Barre syndrome:

Answer 48

the body's immune response to an infection produces antibodies, but due to biomimicry, these also attach to proteins on peripheral neurones

Question 49

Do symptoms progress upwards or downwards in Guillain-Barre syndrome?

Answer 49

Upwards

Question 50

Give two diagnostic investigations for Guillain-Barre syndrome and their positive results:

Answer 50

1) nerve conduction studies (reduced signal) 2) lumbar puncture (CSF will show raised protein but normal cell count and glucose)

Question 51

What is the first line management for Guillain-Barre syndrome?

Answer 51

IV immunoglobulins

Question 52

Give 3 general investigations for peripheral nerve injuries:

Answer 52

1) nerve conduction studies 2) electromyography 3) MRI cerograph/ CT scan

Question 53

What is the most common intervention for peripheral nerve injuries?

Answer 53

surgery