Case 2 - Pain Management Flashcards
(52 cards)
what are the 4 components of pain
- transduction
- transmission
- perception
- modulation
what are nociceptors
sensory receptors that are activated by noxious stimuli that damage or threaten the body integrity.
nociceptors belong to the slowing conducting afferent a delta and C fibres. they are classified according to their response to mechanical, thermal or chemical stimuli.
what is transduction
tissue damage results in the release of inflammatory mediators which bind to nociceptors conveying a thermal, mechanical or chemical insult into an electrical signal
what is transmission
occurs at the level of a second order neurones and there are various tracts that go from the spinal cord to different parts of the brain
what is perception
information has reached the brain and is being interested through the unique cognitive network
what is modulation
descending pathways have quietened down and some of those are sending their electrical impulses and now is integrating the information and modulation from the level of the brain to thespian cord happens at various levels and though different structures in the brain
what are the principles of acute pain management
- enhanced recovery
- management of expectations
- multimodal analgesia
- opioid sparing
what is the WHO ladder not appropriate for
management of acute pain
when was the WHO ladder created
1986
diagram of the WHO ladder
how do NSAIDs reduce tissue inflammation and nociception
by inhibiting prostaglandins
where do NSAIDs mainly act
peripherally
where are selective COX inhibitors more potent
at the COX2 enzyme
what are the side effects of NSAIDs
gastrointestinal irritation and risk to gastrointestinal bleeding
NSAIDs must be used with caution in what patients
older patients with impaired renal function and heart failure
diagram showing prostaglandin production
what do local anaesthetics not work with
abbesses
names of agonist/antagonist opioids
nalbuphrine and pentazocine
what do opioids do
they reduce pain signal transmission by activating pre-synaptic opioid receptors. this leads to reduced intracellular cAMP concentration, decreased calcium ion influx and thus inhibits the release of excitatory neurotransmitters
what are 2 examples of excitatory neurotransmitters
glutamate and substance P
what do opioids do at the post synaptic level
opioid-receptor binding evokes a hyperpolarisation of the neuronal membrane which decreases the probability of the generation of an action potential
what do opioids also function as
inhibitory transmitters of the descending inhibitory pathway
what other supraspiinal structures do they affect
the thalamus, and the limbic system altering the emotional assessment of pain i.e nociceptive sensations are still perceived but is no longer felt as being unpleasant or threatening
what does morphine do
by an action on mu receptors, inhibits the release of several different neurotransmitters including acetylcholine, glutamate and substance P