Peripheral Neuropathy Flashcards
What is the PNS?
Everything out-with the the spinal cord and brain
What are the four different types of nerve fibre?
Large motor fibre - A alpha
Large sensory fibre - A alpha, beta, delta and C
Small sensory fibre - A alpha, beta, delta and C
Autonomic fibre - A delta and C
What are the symptoms of large motor fibre peripheral neuropathy?
Weakness, wasting and unsteadiness
Describe the power, sensation and reflexes of large motor fibre peripheral neuropathy
Power - reduced
Sensation - normal
Reflexes - absent
What are the symptoms of large sensory fibre peripheral neuropathy?
Numbness, parasthesia, unsteadiness
Describe the power, sensation and reflexes of large sensory fibre peripheral neuropathy
Normal power
Vibration then joint position sense reduced sensation
Reflexes are absent
What is the symptom of small fibre peripheral neuropathy?
Pain
Describe the power, sensation and reflexes of small fibre peripheral neuropathy
Power - normal
Sensation - Pin prick and temp reduced
Reflexes - present
What are the symptoms of autonomic peripheral neuropathy?
Dizziness, impotence, nausea and vomiting
Describe the power, sensation and reflexes of autonomic peripheral neuropathy
Normal power
Normal sensation
Normal reflexes
Define radiculopathy
Nerve root pathology
Define plexopathy
Nerve plexus pathology
Name three types of peripheral neuropathy
- mononeuritis multiplex
- mononeuropathy
- length dependant symmetrical
Describe the distribution of mononeuritis/mononeuropathy
Patchy discrete nerves often due to systemic disease
What is the most common plexopathy?
Long thoracic nerve causing scapular winging
What are the two pathological process that can occur in peripheral neuropathy?
Axonal Loss
Demyelination
What investigation can help determine between demyelination and axonal loss?
Nerve conduction studies or biopsy
What is seen on nerve conduction studies in a demyelination neuropathy?
Latency is delayed and amplitude preserved - temporal disperation - AP jitters
Give an example of acute demyelination neuropathy
Guillaine Barre Syndrome
How does guillaine barre syndrome present?
Progressive paraplegia over days up to 4 weeks, associated with sensory symptoms that proceed to weakness. Pain is very common.
Most common - proximal muscles of hip, reflexes are reduced and become slowly absent
How does guillaine barre arise?
Post infective - e.g campylobacter
What is the treatment for guillaine barre?
IV Ig infusion
Plasma exchange if unresponsive to two infusions
Name chronic demyelinating neuropathies
Hereditary neuropathy
Chronic inflammatory demyelinating polyradiculopathy
Who is affected by hereditary neuropathy?
Young people due to a variety of mutations
How does HMSN1 present?
Champagne bottle deformity due to wasting of tibial muscles, long standing arthropathy due to reduced peripheral nerve function - arches in feet and distal joint dysfunction
What can cause axonal neuropathies?
Idiopathic, vasculitis, paraneoplastic, infections, drugs/toxins, metabolic
What can cause autonomic neuropathies?
Chronic - diabetes, amyloidosis, hereditary
Acute - GBS, porphyria
How is peripheral neuropathy managed?
Vasculitic - IV methylprednisolone and cyclophosphamide
Demyelinating - IVIg, steroids, azathioprine/mycophenolate/cyclophosphamide
