Neuropathy Flashcards
what is neuropathy
disease of the peripheral nerves
what is the classification of neuropathy
mononeuropathy - individual nerve
polyneuropathy - many nerves, typically the longest nerves are damaged first (‘glove and stocking’ distribution)
mononeuritis - multiplex-multiple mononeuropathies
what are the affected modalities in neuropathy
sensory - large fibre (crude touch, vibration, proprioception) and small fibre (pain, temp)
motor
autonomic/visceral - digestion, heart rate and BP regulation, sweat, bowel/bladder and sexual functions
may affect one, some or all
what are the two categories of damage in neuropathy
demyelinating and axonal
determining this requires nerve conduction studies
the category is relevant to finding the cause and treatment
what are the clinical features of neuropathy
sensory disturbance
pain (typically burning stabbing or tingling)
weakness accompanied by wasting, loss of reflex
secondary features such as wounds, ulcers or fractures (including chronic poorly healed fractures)
describe mononeuropathy
symptoms reflect dysfunction, in a single peripheral nerve
sensory loss and paraesthesis, and/or motor weakness in select muscle groups
often compressive - nerves are vulnerable at specific site, fractures can also produce these
common mono-neuropathic nerves and compression site
median nerve - carpal tunnel
ulnar nerve - Guyon’s canal (wrist), cubital tunnel (elbow)
radial - axilla, spiral groove of humerus
lateral cutaneous - inguinal ligament
common peroneal - fibular neck
describe carpal tunnel syndrome
most common
pain and paraesthesia, typically at night, patients ‘wake and shake’
loss of function in important hand movements
associations with pregnancy, hypothyroidism, rheumatoid arthritis, diabetes
treatment is surgery or splints
what is polyneuropathy
many nerve fibres affected simultaneously
length dependent - longest nerves affected first, begins in toes>feet>shins, then glove stocking pattern, up to knees, involving hands
what are the causes of polyneuropathy
diabetes (microvascular nerve damage)
alcohol
medications (amiodarone)
b12 deficiency
immune (acute - Guillan-barre syndrome, chronic - CIPD)
hereditary (Charcot-marie tooth disease)
what is Guillan-barre syndrome
acute inflammatory disorder
autoimmune polyneuropathy
often an infectious trigger in prior weeks (c.jejuni)
what is the pathophysiology of GB syndrome
antibodies are generated against infection, then attack similar antigens in peripheral nerves (molecular mimicry)
‘ascending weakness pattern’ (length dependent)
treatment of GB syndrome
neurological emergency (patients require hospitalisation, weakness may affect diaphragm and ventilation may be needed)
supportive measures and IVIg or plasma exchange
what is diabetic neuropathy
chronic slowly progressive condition
associated with longstanding hyperglycaemia
often arises along with retinal and renal disease
what is the pathophysiology of diabetic neuropathy
microvascular damage to nerves, particularly small fibre nerves
poses risk to foot health as patients don’t receive painful stimuli
in association with poor vascular health patients are more prone to wounds with poorer healing
