Mononeuropathies

Question 1

List some generic symptoms for mononeuropathies [3]

Answer 1

1. numbness
2. weak grip
3. tingling

Question 2

What muscle group of the arm and area (ant/post) do the following nerves supply?

1. Radial? [2]
2. Median? [2]

Answer 2

1. Extensors → posterior arm
2. Flexors → anterior arm

Question 3

Radial nerve palsy:

1. most commonly caused by? [1]
2. presenting symptoms? [6]

Answer 3

1. Most commonly caused by entrapment at spiral groove
2. Presenting symptoms:
   
   • wrist and finger drop
   • usually painless
   • motor (muscle) weakness:
     
     • extensor carpi radialis longus → weakness upon wrist extension
     • extensor digitorum communis → weakness upon finger extension
     • brachioradialis → weakness upon elbow flexion in mid-pronation
   • sensory changes (see image)

Question 4

Ulnar nerve palsy:

1. most commonly caused by? [1]
2. presenting symptoms? [8]

Answer 4

1. Most commonly caused by entrapment at ulnar groove (medial epicondyle of humerus)
2. Presenting symptoms
   
   • may be history of trauma at elbow
   • usually painless
   • motor (muscle) weakness
     
     • 1st dorsal interosseus → weakness upon index finger abduction
     • abductor digiti minimi → weakness upon pinkie abduction
     • flexor carpi ulnaris → weakness upon wrist flexion
     • adductor pollicis → weakness upon thumb adduction
   • sensory disturbance and weakness “weak grip” (see image)

Question 5

Median nerve palsy:

1. most commonly caused by? [1]
2. presenting symptoms? [8]

Answer 5

1. Most commonly caused by entrapment within carpal tunnel at wrist
2. Presenting symptoms
   
   • history of intermittent nocturnal pain, numbness and tingling — often relieved by shaking hand
   • patient may complain of “weak grip”
   • positive Tinel’s sign/Phalen’s test
   • motor (muscle) weakness
     
     • lumbricals 1+11 → weakness upon flexion at MCP joints
     • opponens pollicis → weakness upon thumb opposition
     • abductor pollicis brevis → weakness upon thumb abduction
     • flexor pollicis brevis → weakness upon thumb flexion
   • sensory change (see image)

Question 6

Median nerve II: Anterior Interosseous Branch palsy:

1. most commonly caused by? [1]
2. presenting symptoms? [6]

Answer 6

1. Most commonly caused by trauma to forearm
2. Presenting symptoms
   
   • history of forearm pain
   • patient may complain of “weak grip” of keys
   • positive Tinel’s sign/Phalen’s test
   • motor (muscle) weakness
     
     • pronator quadratus → weakness upon flexion at MCP joints
     • flexor pollicus longus → weakness upon thumb flexion
     • flexor digitorum profundus (lateral) → weakness upon thumb flexion

Question 7

Femoral nerve palsy:

1. most commonly caused by? [2]
2. presenting symptoms? [7]

Answer 7

1. Most commonly caused by haemorrhage/trauma
2. Presenting symptoms
   
   • weakness of Quadriceps
   • weakness of Hip flexion
   • numbness in medial shin
   • motor (muscle) weakness
     
     • quadriceps → weakness upon knee extension
     • iliopsoas → weakness upon hip flexion
     • adductor magnus → weakness upon hip adduction
   • Sensory change (see image)

Question 8

Common peroneal nerve palsy:

1. most commonly caused by? [1]
2. presenting symptoms? [6]

Answer 8

1. Most commonly caused by entrapment at fibular head
2. Presenting symptoms
   
   • may be history of trauma, surgery or external compression
   • acute onset foot drop + sensory disturbance
   • usually painless
   • motor (muscle) weakness
     
     • tibialis anterior → weakness of ankle dorsiflexion
     • extensor hallucis longus → weakness upon great toe extension
   • sensory change (see image)

Question 9

What is mononeuritis multiplex? [1]

Answer 9

Simultaneous or sequential development of neuropathy of 2 or more nerves

Question 10

What are the common causes of mononeuritis multiplex? [10]

Answer 10

1. Diabetes
2. Vasculitis
   
   • Churg Strauss
   • polyarteritis nodosa
3. Rheumatological
   
   • Rheumatoid arthritis,
   • Lupus,
   • Sjogren’s syndrome
4. Infective
   
   • Hepatitis C,
   • HIV
5. Sarcoidosis
6. Lymphoma