Peripheral Neuropathies Flashcards
What is a good approach to PNS problems?
Which nerves are damaged? Where are they damaged? How are they damaged (myelin or axonal)? Why are they damaged? Can we stop it?
What are symptoms of large alpha/beta fibre motor problems?
Weakness, unsteadiness, wasting of muscles
Will power be reduced in pathologies of large alpha/beta motor fibres of the PNS?
Yes
Will sensation be intact in pathologies of large alpha/beta motor fibres of the PNS?
Yes
Will reflexes be normal in pathologies of large alpha/beta motor fibres of the PNS?
No - absent
What will the symptoms be in pathologies of large alpha/beta sensory fibres of the PNS?
Numbness, paraesthesia, unsteadiness
Will power be preserved in pathologies of large alpha/beta sensory fibres of the PNS?
Yes, normal power
Will reflexes be normal in pathologies of large alpha/beta sensory fibres of the PNS?
Yes
Will sensation be preserved in pathologies of large alpha/beta sensory fibres of the PNS?
No; vibration and proprioception reduced
Will reflexes be normal in pathologies of large alpha/beta sensory fibres of the PNS?
No - absent
What symptoms will occur with pathologies of the small delta and C fibres of the PNS?
Pain, dysethesia
Will power be preserved with pathologies of the small delta and C fibres of the PNS?
Yes, normal
Will sensation be preserved with pathologies of the small delta and C fibres of the PNS?
No; pin-prick and temperature perception reduced
Will reflexes be normal with pathologies of the small delta and C fibres of the PNS?
Yes
What symptoms will occur with pathologies of delta and C fibres the ANS?
Dizziness (postural hypotension)
Impotence
N+V (gastroparesis)
Will power be preserved with pathologies of delta and C fibres the ANS?
Yes
Will sensation be preserved with pathologies of delta and C fibres the ANS?
Yes
Will reflexes be normal with pathologies of delta and C fibres the ANS?
Yes
What is a high stepping gait?
Foot drop due to weakness of ankle dorsiflexion
What are DDx of a high stepping gait?
Common fibular nerve palsy
L5 palsy
Motor neuropathies; bilateral due to alcohol or diabetes
Where is the nerve damaged in a radiculopathy?
Nerve root; commonly due to a prolapsed disc
What is a mononeuropathy?
Single nerve problem for example a wrist drop due to radial nerve palsy or carpal/ cubital syndrome
What is mononeuritis multiplex?
Vasculitis affecting the blood supply to nerves
What is a length dependent peripheral neuropathy?
Neuropathy due to underlying systemic condition such as diabetes or alcoholism
What distribution of sensory loss will length dependent peripheral neuropathy show?
Glove and stocking
Symmetrical
Are plexopathies painful?
YES
What is the difference between guillan barre syndrome and MS?
Guillain barre = demyelinating disorder of PNS
MS = demyelinating disorder of CNS
What are the acute and chornic demyelinating neuropathies of the PNS?
Acute (days to week): GBS
Chronic (months to years): CIDP, charcot-marie-tooth disease
What are the symptoms of GBS?
Progressive paraplegia over days up to 4 weeks
Assoc sensory symptoms proceed weakness
PAIN very common
When are the peak symptoms of GBS?
10-14 days into onset of illness
What commonly precedes GBS?
Campylobacter
Resp infections
What % of people with GBS will require ventilation?
25%
What will cause the majority of deaths in GBS?
Autonomic failure; cardiac arrhythmias
It will strip the ANS of its myelin
What is the treatment for GBS?
IVIg and/or plasma exchange
Minimal role for steroids
What is charcot marie tooth disease?
Pure motor, sensory, sensorimotor, small fibre and autonomic variants
Demyelinating and axonal variation
Genetic
What is typically seen in CMT?
Wasting of tibial muscles
Deforming arthropathy of hands
Pes cavus
What are the different types of axonal neuropathies?
Vasculitis Paraneoplastic Infections Drugs/ toxins Metabolic
What causes vasculitis axonal neuropathies?
ANCA +ve
RA
Sjogren’s
What causes paraneoplastic axonal neuropathies?
Myeloma Antibody mediated (breast cancer, small cell lung cancer)
What causes infectious axonal neuropathies/
HIV
Syphilis
Lyme disease
Hep B/C (cryoglobulin mediated)
What drugs/toxins cause axonal neuropathies?
ALCOHOL
Amiodarone
Phenytoin
Chemo; cisplatin/ vincristine
What metabolic disorders cause axonal neuropathies?
Diabetes
B12/ folate deficiency
Chronic uraemia
Porphyria - acute intermittent porphyria
What causes chronic autonomic neuropathies?
Diabetes; gastroparesis
Amyloidosis
Hereditary
What will cause acute autonomic neuropathies?
GBC
Porphyria
What is the treatment for axonal neuropathies in general?
Treat cause
Symptomatic; physio, orthotics, neuropathic pain relief
What is the treatment for vasculitis related axonal neuropathies?
Pulsed IV methylprednisolone + cyclophosphamide
What is the treatment for demyelinating neuropathies?
IVIg Steroids Azathioprine Mycophenolate Cyclophosphamide
