Peripheral Neuropathy Flashcards
name all areas that are considered part of the peripheral NS, starting with nerve root and working out towards 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 or 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 damaged?
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 symptoms = dizziness, nausea, vomiting, impotence
where does posterior primary ramus signal to?
back of neck and trunk
where does anterior primary ramus signal to?
limbs: anterior and lateral trunk
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)
how is a length dependent peripheral neuropathy usually distributed?
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 mononeuropathy?
check if muscle is wasted on opposite side of body
what is most common cause of mononeuritis multiplex and why does it cause this?
vasculitis (usually ANCA +ve)
blood supply to nerve gets lost in disease process - acute loss of function and patchy distribution
what plexopathy is common in newborn babies?
Erbs palsy - damage of C5,6 during childbirth when baby’s neck is pushed to side during delivery
what are the two main ways in which nerves can be damaged in a peripheral neuropathy?
axonal loss
demyelination (not MS)
how can you distinguish whether a peripheral neuropathy has been caused by axonal loss or demyelination?
neurophysiology - each gives very distinct signal
what demyelinating disorders of PNS are acute?
gulliane barre syndrome (GBS)
acute inflammatory demyelinating polyneuropathy (AIDP)
what demyelinating disorders of PNS are chronic?
chronic inflammatory demyelinating polyradiculopathy (CIDP)
hereditary sensory motor neuropathy (formerly charcot-marie-tooth disease)
how does GBS usually present?
progressive paraplegia over days up to 4 weeks
associated sensory symptoms before weakness
pain very common
at what day during GBS are symptoms usually at peak?
day 10-14
examination can be normal in initial phases of GBS - true or false?
true
what infection is thought to potentially precipitate GBS?
campylobacter
what causes the mortality associated with GBS?
autonomic nerves become affected and this causes life threatening symptoms eg cardiac arrhythmias
what is treatment for GBS?
immunoglobulin infusion and / or plasma exchange
hereditary neuropathies are usually genetic - true or false?
true
there are lots of varieties of hereditary neuropathies but what is 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) vasculitis paraneoplastic infections drugs/toxins metabolic
what conditions can cause acute autonomic neuropathy?
GBS
porphyrias
how are axonal peripheral neuropathies treated?
treat cause (ie if infection etc)
symptomatic treatment - physio, neuropathic pain relief
if inflammatory vasculitis - steroids and immunosuppression
how are demyelinating peripheral neuropathies treated?
IV immunoglobulin
steroids
immunosuppression
what are paraneoplastic causes of axonal neuropathies?
myeloma antibody mediated (eg breast cancer)
what are infectious causes of axonal neuropathies?
HIV
syphilis
lyme
hepatitis B/C
what are drug / toxin causes of axonal neuropathies?
alcohol
amiodarone
phenytoin
chemotherapy
what are metabolic causes of axonal neuropathies?
diabetes B12 / folate deficiencies hypothyroidism chronic uremia porphyria
