peripheral neuropathy Flashcards
what is a neuropathy?
disorder of the nerve
what is a mononeuropathy?
problem with one nerve
what is polyneuropathy?
problem with many nerves
what is mono neuropathy multiplex?
problems with lots of individual nerves. (different from polyneuropathy as nerves are disseminated and damage is not related)
what is a common example of a mononeuropathy?
carpal tunnel syndrome
what are the defining features of a polyneuropathy/peripheral neuropathy
symmetrical and length dependant
can be:
sensory
motor
sensory and motor
what pain feature is often common with polyneuropathy/peripheral neuropathy?
allodynia
oversensitivity to sensory stimuli
pain due to sensory stimulus that would not ordinarily cause pain
what are the common features of mononeuropathy multiplex?
asymmetrical
random patchy process
vasculitis
inflammatory process
immune process
how can peripheral neuropathies be classified?
according to:
nerves affected
hereditary or acquired
axonal or demyelinating
inflammatory, non-inflammatory
acute or chronic
what are the four commonest causes of peripheral neuropathies
diabetes
idiopathic
leprosy
hiv (in other countries)
what are some uncommon causes of peripheral neuropathy?
Deficiency states e.g. B12 /Folate
Alcohol/Toxins/Drugs
Hereditary Neuropathies
Paraneoplastic Syndromes
Metabolic abnormalities
what investigations can be performed for peripheral neuropathies?
history and examination
+/- neuropathy screen
+/- vasculitis screen
+/- EMG/NCS
+/- CSF study
+/- nerve biopsy
what blood tests should be conducted in a neuropathy?
FBC
ESR
UECR, RBS, TFT, CRP
serum electrophoresis
B12 folate
Anti Gliadin
(TPHA, HIV)
tumour markers?
what blood tests should be conducted for vasculitis?
FBC, ESR
UECr, CRP
ANA, ENA, ANCA
how can you treat a neuropathy
idiopathic- supportive
neuropathic analgesia (gabepentin, amitrptyline)
treat, remove underling cause eg DM/gluten
what are the featues of hereditary neuropathy?
tend to be symmetrical
length dependent • i.e. polyneuropathy / peripheral neuropathy
name three common causes of hereditary neuropathy
charcot marie tooth disease (CMT)
hereditary motor sensory neuropathy (HMSN)
axonal/demyelinating or mixed
what are the clinical signs of CMT
slow over many years
length dependant
motor or sensory
sometimes very little symptoms but signs present
pes cavus
what is pes cavus
clawing of the foot
high arch & relatively stiff
what are the four main categories of CMT?
CMT1 (demyelinating)
CMT2 (Axonal)
X LINKED
intermediate CMT
CMT1 AND 2 are either:
autosomal dominant or autosomal recessive
what gene is commonly responsible for AD cmt1a
PMP22
what is PMP22
peripheral myelin protein gene on chromosome 22
mutations of PMP22 can cause?
CMT1a
deletions in PMP22 can cause?
HLPP/ HNPP
hereditary neuropathy with liability to pressure palsies
what does PMP do?
makes the protein which forms part of the schwann cells /myelin sheath
can can deletion lead to demyelination
overproduction of PMP22 due to duplication leads to interuption in PMP processing and interupts other Schwann cell functions •
without PMP22, myelin is unstable and degenerates - demyelination
what is CMT1b
much less common varient of CMT
MPZ mutation
can be classical CMT or more severe and early onset
what are the three types of CMT2
CLASSICAL
CMT2 +sensory (especially if pain)
CMT+ upper limb onset
