Go over the types of nerve fibres and associated symptoms
Define what is meant by the term peripheral neuropathy
Is damage to or disease affecting nerves, which may impair sensation, movement, gland or organ function
Define what is meant by the term Pseudoathetosis
This is abnormal writhing movements, usually of the fingers, caused by a failure of joint position sense (proprioception) and indicates disruption of the proprioceptive pathway, from nerve to parietal cortex.
https://www.youtube.com/watch?v=g3JTZObWGFA
What is a ‘high stepping gait’ characteristic of ?
Bilateral Foot drop - due to the patient not being able to dorsiflex, causing the toes to scrape the ground while walking, requiring someone to lift the leg higher than normal
Define what a mononeuropathy is
These are lesions of individual peripheral or cranial nerves causes are usually local such as truama or entrapment e.g. from a tumour
Define what mononeuritis multiplex is
This is if 2 or more peripheral nerves are affected, this is more when causes tend to be systemic
What is a radiculopathy ?
Radiculopathy = irritation of or injury to a nerve root (as from being compressed) that typically causes pain, numbness, or weakness in the part of the body which is supplied with nerves from that root.
Most common cause = Herniated disc
What is a plexopathy ?
Plexopathy is a disorder affecting a network of nerves, blood vessels, or lymph vessels. The region of nerves it affects are at the brachial or lumbosacral plexus. Symptoms include pain, loss of motor control, and sensory deficits.
What are the typical patterns seen in median nerve injury ?
Damage at wrist
- e.g. carpal tunnel syndrome
- paralysis and wasting of thenar eminence muscles and opponens pollicis (ape hand deformity)
- sensory loss to palmar aspect of lateral (radial) 2 ½ fingers
Damage at elbow, as above plus:
- unable to pronate forearm
- weak wrist flexion
- ulnar deviation of wrist
What is the typical pattern seen in ulnar nerve damage
Damage at wrist
- ‘claw hand’ - hyperextension of the metacarpophalangeal joints and flexion at the distal and proximal interphalangeal joints of the 4th and 5th digits
- wasting and paralysis of intrinsic hand muscles (except lateral two lumbricals)
- wasting and paralysis of hypothenar muscles
- sensory loss to the medial 1 1/2 fingers (palmar and dorsal aspects)
What is the typical pattern seen indicative of radial nerve injury ?
Patterns of damage
- Wrist drop
- Sensory loss to small area between the dorsal aspect of the 1st and 2nd metacarpals
What is the typical pattern seen in common peroneal nerve injury?
Other features include:
- weakness of foot dorsiflexion
- weakness of foot eversion
- weakness of extensor hallucis longus
- sensory loss over the dorsum of the foot and the lower lateral part of the leg
- wasting of the anterior tibial and peroneal muscles
Often due to damage as it winds round the fibular head e.g. truama, sitting corss-legged etc
What is the typical pattern of tibial nerve injury ?
Cant plantarflex (cant stand on tip-toes)
What can nerve conduction studies help determine ?
If it is a demyelinating neuropathy
What is a polyneuropathy ?
This is a disorder of peripheral or cranial nerves, whose distribution is usually symmetrical and widespread, often with distal weakness and sensory loss (glove and stocking pattern)
What is the most common pattern of peripheral neuropathies ?
- Glove and stocking distribution - pics show mild, moderate and severe forms of glove and stocking distribution
- You usually get sensory symptoms and then motor symptoms
- Refer back to the table with the types of nerve fibres affected
How are polyneuropathies classified?
In a number of ways:
- Acute or chronic
- By function i.e. sensory, motor or mixed
- Or by pathology - axonal degeneration or demyelination
What are the sensory symptoms people with neuropathies may experience ?
- Numbness
- pins and needles
- feels funny,
- burning
- Pain
What are the motor symptoms people with neuropathies may experience
- Wasting and weakness most markedly in the distal muscles of hands and feet
- reduced or absent reflexes
- Difficulty breathing
- Clumsy hands or difficulty walking
What are the main types of demyelinating neuropathies ?
Acute (days to weeks):
- GBS (Guillaine Barre syndrome or AIDP)
Chronic (Months to years):
- CIDP (chronic inflammatory demyelinating polyradiculopathy).
- Hereditary sensory motor neuropathy (formerly known as Charcot-Marie-Tooth disease)
Describe the typical presentation of guillian barre syndrome
- Usually occurs following infection esp campylobacter GI infection.
- It causes symmetrical progressive weakness of all the limbs with the legs usually being affected first in an ascending mannor.
- Reflexes are absent or reduced.
- Sensory symptoms usually follow weakness and are mild but include paraesthesia and pain
- Resp muscle weakness
- CN involvement - diplopia, bilateral facial nerve palsy, oropharyngeal weakness
- Autonomic involvement - urinary retention, diarrhoea.
What do a lot of patients require who get guillian barre syndrome and what do some patients die from ?
- 25% require mechanical ventilation
- 10% die mainly from autonomic failure (cardiac arrythmia)
What investigations are done in someone with guillian barre syndrome?
LP and nerve conduction studies.
What is the treatment of guillian barre syndrome ?
- 1st line = IV immunoglobulin
- 2nd line = plasma exchange
