Peripheral Neuropathy Flashcards
Name all areas that are considered part of the peripheral nervous system, starting with the nerve root and working out towards the muscle?
nerve root spinal nerve rami plexus peripheral nerve NMJ muscle fibres
Symptoms of peripheral neuropathy are related to the type of nerve fibres involved. TRUE/FALSE?
TRUE
Damage to what type of fibres causes motor symptoms?
A-alpha
What symptoms are present if A-alpha fibres (large motor) are damaged?
Weakness
Unsteadiness
Muscle wasting
What fibres are considered large sensory fibres?
A-alpha and A-beta
What symptoms are present if large sensory fibres are dmamaged?
numbness
parasthesia
unsteadiness
lack of proprioception
What do small A delta and C fibres control?
pain
temperature regulation
autonomic functions
What symptoms can be seen if a-delta and c fibres are damaged?
pain
dysethesia
autonomic symp: dizzy, N+V, impotence
What areas of the peripheral nervous system can be damaged to cause a neuropathy?
Nerve Root => radiculopathy
Plexus => Plexopathy
Peripheral Nerve
What are the different categories of peripheral nerve neuropathy?
=> Mononeuropathy (one named nerve)
=> Mononeuritis Multiplex (patchy distribution)
=> (length dependent) Peripheral Neuropathy (usually bilateral and driven by illness e.g. diabetes
How is a (length dependent) Peripheral Neuropathy usually distributed across the body?
weakness and or sensory loss in glove and stocking distribution
What should you always check if you notice muscle wasting in a patient and assume they have a mononeuropathy?
Check if muscle is wasted on opposite side of body
What is the most common cause of mononeuritis multiplex and why does it cause this?
Vasculitis (usually ANCA +ve)
Blood supply to the nerve gets lost in disease process
=> patients have acute loss of function
=> patchy distribution of loss
What plexopathy is common in newborn babies?
Erb’s Palsy
- damage of C5,6 during childbirth when baby’s neck is pushed to side during difficult delivery
What are the two main ways in which nerves can be damaged in a peripheral neuropathy?
Axonal Loss
Demyelination (NOT MS)
How can we distinguish whether a peripheral neuropathy has been caused by axonal loss or by demyelination?
Neurophysiology
- each gives very distinct signal
What demyelinating disorders of the PNS are ACUTE?
Guillain Barre syndrome (GBS)
Acute Inflammatory Demyelinating Polyneuropathy (AIDP)
WHat demyleinating disorders of the peripheral NS are chronic?
Chronic inflammatory demyelinating polyradiculopathy (CIDP)
Hereditary sensory motor neuropathy (formerly Charcot-Marie-Tooth disease)
How does Guillain-Barre syndrome usually present?
- Progressive paraplegia over days up to 4 weeks
- Associated sensory symptoms before weakness
- Pain very common
At what day during Guillain-Barre syndrome are symptoms usually at their peak?
Day 10-14
Examination can be normal in the initial phases of Guillain-Barre syndrome. TRUE/FALSE?
TRUE
What infection is thought to potentially precipitate guillain-barre syndrome?
Campylobacter
What causes the mortality associated with Guillain-barre syndrome?
Autonomic nerves become affected and cause life threatening symptoms e.g. cardiac arrhythmias
What treatment is used for guillain-barre syndrome?
immunoglobulin infusion and or Plasma exchange
Hereditary neuropathies are usually genetic. TRUE/FALSE?
TRUE
Lots of varieties of hereditary neuropathies, but one of the most common mutations = CMT1a
How are hereditary sensory motor neuropathies normally noticed clinically?
Longstanding loss of muscle (especially tibial)
pes planus
thin distal musculature
joints not well formed due to disease since childhood
What are the main causes of axonal neuropathies?
Idiopathic (age related) Vasculitic Paraneoplastic Infections Drugs/Toxins Metabolic
What conditions can cause a chronic autonomic neuropathy?
Diabetes
Amyloidosis
What conditions can cause an acute autonomic neuropathy?
Guillain-Barre (this is the cause of mortality in this condition)
Porphyrias
How are axonal peripheral neuropathies treated?
Treat cause (ie treat infection etc)
Symptomatic treatment – physiotherapy, neuropathic pain relief.
If inflammatory vasculitis - steroids and immunosuppression
How are demyelinating peripheral neuropathies treated?
IV Immunoglobulin
Steroids
Immunosuppression
