Peripheral Nerve Lesions Flashcards
What happens in terms of motor function in nerves affected by peripheral neuropathy?
Reduced power, tone or reflexes
What are the two main causes of peripheral nerve lesions?
Axonal loss or peripheral demyelination
What symptoms can arise as a result of an autonomic neuropathy?
Dizziness (postural hypotension), nausea and vomiting, impotence, problems with bladder and bowel control
What do small fibre neuropathies cause?
Pain and dyesthesia, reduced pinprick and temperature sensation (no motor features)
What is an example of a small fibre neuropathy? How does the damage causing these come about?
Congenital insensitivity to pain syndrome / axonal loss only (can’t be demyelination since they are not myelinated)
Describe what happens in mononeuritis multiplex?
Multiple single nerves are affected one by one
What is likely to be the cause of mononeuritis multiplex?
Usually the result of a systemic condition e.g. vasculitis
What is Charcot-Marie-Tooth disease?
A clinically and genetically distinct cause of inherited neuropathy
How does Charcot-Marie-Tooth disease present?
Symmetrical distal wasting and weakness, as well as foot deformities e.g. pes cavus, hammer toes
Describe the onset of Charcot-Marie-Tooth disease?
A more chronic presentation which comes on over months-years
What is the most common inflammatory, immune mediated polyneuropathy?
Guillain Barre syndrome
Describe the onset of Guillain Barre syndrome?
Must develop within 6 weeks, usually reaching a peak at 2 weeks
What is a condition similar to Guillain Barre syndrome but is less severe and relapsing?
Chronic inflammatory demyelinating polyneuropathy
How does Guillain Barre syndrome usually present?
Sensory symptoms which progress to motor, with flaccid weakness starting in the legs and progressing to the arms
What often precedes Guillain Barre syndrome?
A respiratory or GI infection
Aside from motor features of the extremities, what are some other features which can be seen in Guillain Barre syndrome?
Bulbar weakness, often causing dysphagia and dysarthria and can also get cranial nerve involvement. Respiratory muscle involvement can also occur.
What happens to reflexes in Guillain Barre syndrome?
Can be normal at the beginning but will eventually be lost
Is Guillain Barre syndrome painful?
Yes, back pain from nerve root inflammation is common
What is a condition which can cause mixed UMN and LMN signs? Explain this.
B12 deficiency - causes degeneration of spinal cord tracts and peripheral nerves
10% of people with Guillain Barre syndrome die from what?
Autonomic involvement causing arrhythmias
How should Guillain Barre syndrome be treated?
IV immunoglobulin infusion, potentially plasma exchange
How long does it take to recover from Guillain Barre syndrome?
Months-years
What will a CSF sample of inflammatory peripheral neuropathy show?
Mildly raised WCC, high protein
What is the main investigation used to help decipher between different types of neuropathy?
Nerve conduction studies
