Compressive Neuropathies Flashcards
Where will the symptoms and signs of compressive neuropathies affect?
The peripheral nerve’s sensory and motor territories
What is the most common upper limb compressive neuropathy?
Carpal tunnel
What forms the carpal tunnel of the wrist?
Carpal bones and flexor retinaculum
What structures pass through the carpal tunnel?
The medial nerve, and 9 flexor tendons
What are the flexor tendons which pass through the carpal tunnel covered with?
Synovium
Any swelling within the confines of the carpal tunnel may result in what?
Median nerve compression
Most cases of carpal tunnel are what?
Idiopathic
What conditions can cause carpal tunnel?
Rheumatoid arthritis, and any condition which results in fluid retention
Why does rheumatoid arthritis cause carpal tunnel?
Synovitis of the flexor tendons means there is less space in the tunnel
What conditions can increase fluid retention to cause carpal tunnel?
Pregnancy, diabetes, chronic renal failure, hypothyroidism
What traumatic injury is most likely to cause carpal tunnel?
Wrist fractures, especially a Colles fracture
If you get carpal tunnel when you are pregnant, do the symptoms go away?
Yes, usually after childbirth
Which sex is more likely to be affected by carpal tunnel? By how much?
Females, 8 times
How will patients with carpal tunnel present?
Paraesthesia in the median nerve innervated digits. There may be weakness of the thumb or clumsiness in the area of the hand supplied by the median nerve.
What are the median nerve innervated digits?
The thumb, and the radial 2 and a half fingers (half of ring finger nearest to middle finger)
When is the parasthesia of carpal tunnel often worse?
At night
What may be seen on examination of carpal tunnel?
Loss of sensation and/or muscle wasting of the thenar eminence
What is Tinel’s test?
Percussing over the median nerve to test for carpal tunnel
What is Phalen’s test?
Holding the wrist hyper flexed to decrease the space in the carpal tunnel to test for carpal tunnel syndrome
What investigation can be used to confirm a diagnosis of carpal tunnel? What will it show?
Nerve conduction studies- show slowing of conduction across the wrist
What are some non-surgical treatment options for carpal tunnel?
Wrist splints at night to prevent flexion, corticosteroid injections
What surgical treatment can be used for carpal tunnel?
Carpal tunnel decompression: division of the transverse carpal ligaments under local anaesthetic
What are the outcomes of surgery for carpal tunnel? What is the risk?
Highly successful surgery. Risk of damage to the median nerve or one of its smaller branches.
Cubital tunnel syndrome involves compression of which nerve?
Ulnar nerve
Where does the nerve get compressed in cubital tunnel?
At the elbow, behind the medial epicondyle
What is the main complaint of patients with cubital tunnel?
Paraesthesia in the ulnar 1 1/2 fingers
Is there any overlap of the fingers affected by cubital/carpal tunnel?
No
Weakness of the ulnar nerve innervated muscles may be present in cubital tunnel- what are these?
First dorsal interosseous and adductor pollicis
What movement does the first dorsal interosseous muscle allow?
Abduction of index finger
Weakness of which muscle is assessed with Froment’s test?
Adductor pollicis
What can compression in cubital tunnel be due to?
A tight band of fascia forming the roof of the tunnel OR tightness at the inter muscular septum that the nerve passes through
What inter muscular septum must the ulnar nerve pass through which can be a cause of cubital tunnel?
Between the two heads at the origin of flexor carpi ulnaris
What test can be used to confirm cubital tunnel syndrome?
Nerve conduction studies
How can cubital tunnel be treated?
Surgical release of any tight structures
