physiology of pain 2 Flashcards
How long does clinical pain last
Pain could be acute or chronic
acute= pain< 3 months
chronic= pain> 3months
Outline the mechanism of acute pain
Due to excitation of nociceptors, maybe direct via binding due to atp, protons or seretonin.
may also be due to peripheral sensitisation where the pain response is exaggerated (hyperalgesia)
how do we treat acute pain
sites of action are: PNS, CNS or both
local anaesthetics: lidocaine, lignocaine which act in the periphery.
they prevent nociceptors firing by blocking sodium channels.
Outline NSAID’s
examples are aspirin, ibuprofen
they act in the periphery and they reduce inflammation by inhibiting prostaglandin synthesis and reduce peripheral sensitisation.
COX inhibited, Prostaglandin synthesis reduced and prevents a decrease in sodium channel threshold.
How does topical capsaicin treatment work
They are TRPV1 channel agonists, persistent opening of TRPV1 and there is calcium overload and nociceptors stop working due to mitochondrial dysfunction.
How do opioids work
they act centrally and peripherally, mechanism of action: agonists of the endogenous opioid system which acts on the brainstem, spinal cord and peripheral.
Outline gate control theory
Pain evoked by nociceptors can be reduced by the simultaneous activation of low threshold mechanoreceptors (A-beta fibres)
simply put, rubbing or blowing on the painful area can reduce the pain.
Outliune neuropathic pain
Due to a lesion affecting the NS, maybe a compression, traction, sever, tumour etc
What are some treatments for neuropathic pain
Drugs: anticonvulsants, tricyclic antidepressants and topical capsaicin or lidocaine.
acupuncture, physical therapies, psychological therapies (CBT) and surgery (spinal cord stimulator)
