Neuropathy

Question 1

What are the different presentation forms of peripheral neuropathy?

Answer 1

• motor
• sensory
• autonomic -> urinary incontinence & postural hypotension

Question 2

What are the risk factors for peripheral neuropathy?

Answer 2

• old age
• hypothyroidism
• diabetes
• vitamin B12 deficiency
• HIV

Question 3

What are the types of mononeuropathy?

Answer 3

• median nerve -> carpal tunnel syndrome
• radial nerve -> crutches & Saturday night
• ulnar nerve -> cubital tunnel syndrome
• tibial nerve -> tarsal tunnel syndrome
• perineal nerve -> thigh high boots & casts
• lateral femoral cutaneous nerve -> meralgia peristhetica (sudden weight loss or gain)

Question 4

What are the types of polyneuropathies?

Answer 4

• inflammatory -> GBS, CIDP, vasculitis
• infectious -> leprosy, HIV
• systemic -> diabetes

Question 5

What is the supply of the median nerve?

Answer 5

Sensory 
- finger I, II, III, & half of IV
Motor 
- flexor carpi radials 
- abductor pollicis Brevis (ABP) 
- opponens pollicis (OP)
- palmaris longus

Question 6

What are the types of median neuropathies & what are their deformities?

Answer 6

• Proximal median neuropathy -> Benedict

- median neuropathy at wrist -> ape hand

Question 7

What is the clinical picture of a proximal median neuropathy?

Answer 7

Benedict’s hand

• weakness of flexor carpi radialis -> inability to flex fingers I, II, & III
• loss of sensation on the radial side of the palm

Question 8

What is the clinical picture of median neuropathy at the wrist?

Answer 8

Ape hand

• thickening of transverse carpal ligament
• weakness of ABP & OP

Question 9

How is a median nerve injury at the wrist treated?

Answer 9

• splint
• median nerve injection
• surgical decompression -> refractory cases or weakness

Question 10

What is the supply of the radial nerve?

Answer 10

Motor
- all extensors of the arm
Sensory
- lateral aspect of forearm

Question 11

What are the sites of radial nerve injury?

Answer 11

Axilla -> paralysis of the triceps muscle
- improper crutch use

Midarm -> wrist drop

• Saturday night palsy, anesthesia, or sleep (honeymoon) -> numbness, paresthesia, & pain along lateral posterior arm
• Fracture of the humerus

Question 12

What is the innervation of the ulnar nerve?

Answer 12

Sensory
- dorsal & palmar surface of medial 1 & a half fingers

Motor

• 3rd & 4th Lumbricals
• dorsal & palmar interossei
• adductor pollicis
• abductor digiti minimi
• flexor carpi ulnaris
• flexor digiti minimi

Question 13

What are the causes of ulnar neuropathy?

Answer 13

• cubital tunnel syndrome -> prolonged leaning on flexed elbow, athletic activity (bench press)
• Guyon’s canal syndrome -> cycling

Question 14

What is the clinical picture of ulnar neuropathy?

Answer 14

• atrophy of hypothenar muscles
• claw hand deformity
• Froment sign
• Wartenberg sign
• positive Tinel’s sign