Peripheral nerve injuries/palsies (N) Flashcards
Define peripheral nerve injuries.
Result from systemic diseases (e.g. diabetes or autoimmune disease) or localised damage (e.g. trauma, compression, tumours) and manifest with neurological deficits distal to the level of the lesion
What are the types of causes of peripheral nerve injuries? (6)
- injury - accidents can compress, crush or cut nerves
- medical conditions - DM, GBS, carpal tunnel syndrome
- autoimmune diseases - SLE, RA, Sjogren’s syndrome
- infection - HIV
- tumour/malignancy
- toxic/metabolic causes - drugs, alcohol, B12, uraemia, amyloidosis
What is Guillain-Barre syndrome (cause of peripheral nerve injuries)?
Immune-mediated demyelination of peripheral nervous system often triggered weeks after an infection (Campylobacter jejuni)
What are the symptoms of Guillain-Barre syndrome? (4)
- back/leg pain initially
- progressive, symmetrical weakness of all limbs
- classically ascending weakness of limbs (legs –> arms)
- reflexes are absent
What would lumbar puncture show in Guillain-Barre syndrome?
Rise in protein with normal WCC
What would a nerve conduction study show in Guillain-Barre syndrome?
Decrease due to demyelination
What is carpal tunnel syndrome (cause of peripheral nerve injury)?
Compression of median nerve in carpal tunnel
What are some causes of carpal tunnel syndrome? (3)
- pregnancy
- rheumatoid arthritis
- oedema
What are the symptoms of carpal tunnel syndrome? (5)
- pins and needles in thumb, index and middle finger
- weakness of thumb abduction
- wasting of thenar eminence
- Tinel’s sign - tapping causes paraesthesia
- Phalen’s sign - flexion of wrist causes symptoms
What investigations do we do for carpal tunnel syndrome?
Nerve conduction studies or EMG
How do we treat carpal tunnel syndrome? (3)
- steroid injections
- wrist splints at night
- severe - surgical decompression
What are the types of nerve damage? (4)
- neuropraxia - compression injury causing temporary disruption of nerve conduction
- axonotmesis - axon damaged but perineurium and epineurium remain intact
- neurotmesis - complete nerve transection
- traumatic neuroma - benign, painful nodular thickening caused by nerve regeneration at site of different forms of nerve injury
What are the clinical features of motor nerve injuries? (3)
- muscle weakness
- painful cramps
- uncontrollable muscle twitching
What are the clinical features of sensory nerve injuries? (2)
- paraesthesia in hands and feet (numbness and tingling)
- trouble sensing pain or changes in temperature
What are the clinical features of autonomic nerve injuries? (4)
- excessive sweating
- changes in blood pressure
- inability to tolerate heat
- GI symptoms
What types of peripheral nerve palsies are there? (7)
- median nerve injuries
- ulnar nerve injuries
- radial nerve injuries
- Klumpske’s palsy
- Erb’s palsy
- common peroneal nerve injuries
- tibial nerve injuries
- (long thoracic, axillary, posterior interosseus, anterior interosseus, meralgia paraesthetica, obturator, sciatic, femoral, tarsal tunnel syndrome)
What are the clinical features of median nerve injuries? (3)
- loss of sensation in lateral palmar surface of 3.5 digits
- weakness in abductor pollicis brevis (thumb abduction)
- wasting of thenar eminence
What signs are seen in median nerve injuries? (2)
- Tinel’s sign - tapping causes paraesthesia
- Phalen’s sign - flexion of wrist causes symptoms
What condition is the median nerve commonly affected in?
Carpal tunnel syndrome
What levels of the spinal cord are affected in median nerve injuries?
C6-T1
What are the clinical features of ulnar nerve injuries? (4)
- loss of sensation over medial 1.5 digits
- weakness in abductor digiti minimi
- wasting of hypothenar eminence
- claw hand
What levels of the spinal cord are affected in ulnar nerve injuries?
C8-T1
What are the clinical features of radial nerve injuries? (2)
- paraesthesia of first dorsal interosseus muscle
- weakness of wrist extension –> wrist drop
What levels of the spinal cord are affected in radial nerve injuries?
C5-T1
What are the clinical features of Klumpke’s palsy? (3)
- loss of sensation in ulnar distribution (medial 1.5 digits)
- paralysis of intrinsic muscles of hand
- Horner’s syndrome sometimes present
What levels of the spinal cord are affected in Klumpke’s palsy?
C8-T1
What are the clinical features of Erb’s palsy? (3)
- loss of shoulder abduction and elbow flexion
- arm held internally rotated
- Waiter’s tip
What levels of the spinal cord are affected in Erb’s palsy?
C5-C6
What are the clinical features of common peroneal nerve injuries? (3)
- sensory loss over dorsum of foot
- weakness in dorsiflexion and eversion of foot –> foot drop
- hit in side of knee
What levels of the spinal cord are affected in common peroneal nerve injuries?
L4-S1
What is a sign of L5 radiculopathy?
Weakness of hip abduction and loss of inversion of foot
What are the clinical features of tibial nerve injuries? (2)
- sensory loss on sole of foot
- inability to invert foot or stand on tiptoe (plantarflexion)
What levels of the spinal cord are affected in tibial nerve injuries?
L4-S3
What are the main methods of investigating peripheral nerve injuries? (2)
- EMG (electromyography)
- nerve conduction studies
What imaging can we do for peripheral nerve injuries?
Plain X-ray or CT/MRI
What conservative treatment is there for peripheral nerve injuries? (6)
- expectant management (allowing spontaneous recovery with close monitoring)
- activity modification
- splinting
- electrical stimulation
- physiotherapy
- analgesia
What surgical treatment is there for peripheral nerve injuries?
Nerve repair or nerve transfer - if injury not healing properly on its own/conservative Rx, or open injury