Peripheral Neuropathy

Question 1

name all areas that are considered part of the peripheral NS, starting with nerve root and working out towards muscle?

Answer 1

nerve root 
spinal nerve 
rami 
plexus 
peripheral nerve 
NMJ 
muscle fibres

Question 2

symptoms of peripheral neuropathy are related to the type of nerve fibres involved - true or false?

Answer 2

true

Question 3

damage to what type of fibres causes motor symptoms?

Answer 3

a-alpha

Question 4

what symptoms are present if a-alpha fibres (large motor) are damaged?

Answer 4

weakness
unsteadiness
muscle wasting

Question 5

what fibres are considered large sensory fibres?

Answer 5

a-alpha and a-beta

Question 6

what symptoms are present if large sensory fibres are damaged?

Answer 6

numbness
parasthesia
unsteadiness
lack of proprioception

Question 7

what do small A delta and C fibres control?

Answer 7

pain
temperature regulation
autonomic functions

Question 8

what symptoms can be seen if a-delta and C fibres are damaged?

Answer 8

pain
dysethesia

autonomic symptoms = dizziness, nausea, vomiting, impotence

Question 9

where does posterior primary ramus signal to?

Answer 9

back of neck and trunk

Question 10

where does anterior primary ramus signal to?

Answer 10

limbs: anterior and lateral trunk

Question 11

what areas of the peripheral nervous system can be damaged to cause a neuropathy?

Answer 11

nerve root = radiculopathy

plexus = plexopathy

peripheral nerve

Question 12

what are the different categories of peripheral nerve neuropathy?

Answer 12

mononeuropathy (one named nerve)

mononeuritis multiplex (patchy distribution)

length dependent peripheral neuropathy (usually bilateral and driven by illness)

Question 13

how is a length dependent peripheral neuropathy usually distributed?

Answer 13

weakness and or sensory loss in glove and stocking distribution

Question 14

what should you always check if you notice muscle wasting in a patient and assume they have mononeuropathy?

Answer 14

check if muscle is wasted on opposite side of body

Question 15

what is most common cause of mononeuritis multiplex and why does it cause this?

Answer 15

vasculitis (usually ANCA +ve)

blood supply to nerve gets lost in disease process - acute loss of function and patchy distribution

Question 16

what plexopathy is common in newborn babies?

Answer 16

Erbs palsy - damage of C5,6 during childbirth when baby’s neck is pushed to side during delivery

Question 17

what are the two main ways in which nerves can be damaged in a peripheral neuropathy?

Answer 17

axonal loss

demyelination (not MS)

Question 18

how can you distinguish whether a peripheral neuropathy has been caused by axonal loss or demyelination?

Answer 18

neurophysiology - each gives very distinct signal

Question 19

what demyelinating disorders of PNS are acute?

Answer 19

gulliane barre syndrome (GBS)

acute inflammatory demyelinating polyneuropathy (AIDP)

Question 20

what demyelinating disorders of PNS are chronic?

Answer 20

chronic inflammatory demyelinating polyradiculopathy (CIDP)

hereditary sensory motor neuropathy (formerly charcot-marie-tooth disease)

Question 21

how does GBS usually present?

Answer 21

progressive paraplegia over days up to 4 weeks
associated sensory symptoms before weakness
pain very common

Question 22

at what day during GBS are symptoms usually at peak?

Answer 22

day 10-14

Question 23

examination can be normal in initial phases of GBS - true or false?

Answer 23

true

Question 24

what infection is thought to potentially precipitate GBS?

Answer 24

campylobacter

Question 25

what causes the mortality associated with GBS?

Answer 25

autonomic nerves become affected and this causes life threatening symptoms eg cardiac arrhythmias

Question 26

what is treatment for GBS?

Answer 26

immunoglobulin infusion and / or plasma exchange

Question 27

hereditary neuropathies are usually genetic - true or false?

Answer 27

true

Question 28

there are lots of varieties of hereditary neuropathies but what is one of the most common mutations?

Answer 28

CMT1a

Question 29

how are hereditary sensory motor neuropathies normally noticed clinically?

Answer 29

longstanding loss of muscle (especially tibial)
pes planus
thin distal musculature
joints not well formed due to disease since childhood

Question 30

what are the main causes of axonal neuropathies?

Answer 30

idiopathic (age related)
vasculitis 
paraneoplastic 
infections
drugs/toxins 
metabolic

Question 31

what conditions can cause acute autonomic neuropathy?

Answer 31

GBS

porphyrias

Question 32

how are axonal peripheral neuropathies treated?

Answer 32

treat cause (ie if infection etc)

symptomatic treatment - physio, neuropathic pain relief

if inflammatory vasculitis - steroids and immunosuppression

Question 33

how are demyelinating peripheral neuropathies treated?

Answer 33

IV immunoglobulin
steroids
immunosuppression

Question 34

what are paraneoplastic causes of axonal neuropathies?

Answer 34

myeloma 
antibody mediated (eg breast cancer)

Question 35

what are infectious causes of axonal neuropathies?

Answer 35

HIV
syphilis
lyme
hepatitis B/C

Question 36

what are drug / toxin causes of axonal neuropathies?

Answer 36

alcohol
amiodarone
phenytoin
chemotherapy

Question 37

what are metabolic causes of axonal neuropathies?

Answer 37

diabetes 
B12 / folate deficiencies 
hypothyroidism
chronic uremia 
porphyria