Flashcards in Management of Chronic Pain Deck (18):
what is pain?
an unpleasant sensory and emotional experience, associated with actual tissue damage or described in terms of such damage
what fibres transmit painful stimulus from skin to spinal cord?
what is released in spinal cord?
substance P and glutamate released to lamina I and V
what in the brain in associated with sensory pain perception?
lamina V projects stimulus to thalamus which signals to somatosensory cortex
what in the brain is associated with affective pain perception (attention to pain)?
lamina I projects stimulus to parabrachial which signals to amygdala hypothalamus
peripheral tissue injury changes the nervous system in what two ways?
peripheral sensitisation - a reduction in the threshold of peripheral afferent nociceptors
central sensitisation - increased excitability of spinal neurones, rewiring in spinal cord and changes in the brain
what are 6 characteristics of chronic regional pain syndrome?
hair and nail changes
what is nociceptive pain?
pain from injury relayed through a normal NS
what is neuropathic pain?
pain generated within nervous system
what does neuropathic pain feel like?
burning, shooting, tingling, sensitivity
what is seen on examination in neuropathic pain?
- allodynia (pain from stimulus that not normally painful eg cotton wool)
- hyperalgesia (more pain than expected from painful stimulus eg pin prick)
what are common causes of neuropathic pain?
post herpetic neuralgia
many unknown origin
how can neuropathic pain be biologically managed?
tricyclic antidepressants - amitriptyline
anticonvulsants - gabapentin
also opioids, NMDA antagonists, sodium channel blockers, capsaicin and GABA agonists
what drugs are more often used in children?
tricyclics - amitriptyline
gabapentin or pregabalin
what can cause chronic pain in cancer survivor?
post surgical pain
chemo induced peripheral neuropathy
chronic graft vs host disease
radiation induced pain
hormonal therapy and arthralgias
other than medication, what else could be used in chronic pain?
intrathecal drug delivery systems
spinal cord stimulation
what gene could contribute to chronic pain?
SCN9A if absent - no pain
SCN9A if abnormal - increased pain