Management of chronic pain Flashcards
Pain definition?
An unpleasant sensory and emotional experience, associated with actual tissue damage, or described in terms of such damage.
difference between acute and chronic pain?
Acute: Usually obvious tissue damage Protective function inc nervous system activity Pain resolves on healing
Chronic pain beyond expected period of healing Pain no longer serves a useful purpose changes in pan signalling and detection Degrades health & function
Assessment of pain
-should include what?
-rate your pain out of 10?
does the patent look like they are in pain
behavioural observation
(grimacing, rigid body posture, limping, frowning or crying)
physiologic response
(inc BP, pulse?)
Why can pain be considered both a sensation and an emotion?
APs from lamina I go both to the thalamus & somatosensory cortex and also to the Amygdala hypothalamus
What are the 2 types of pain?
Nociceptive
(appropriate response to painful stimuli via intact Ns)
Neuropathic
(inappropriate response cause by dysfunctional NS)
Neuropathic pain
- features? (4)
- examination? (2)
- common causes? (5)
- burning, showing, tingling, sensitivity
- sensory changes: Allodynia & Hyperalgesia
-shingles- post herpetic neuralgia surgery Trauma DM amputation
pharmacological approaches?
- WHO ladder?
- Adjuvants? (3)
-non-opioid analgesics (e.g. NSAIDs, paracetamol) Opioid analgesics (e.g. tramadol, codeine, morphine, oxycodone)
-Antidepressants (amitriptyline, duloxetine)
Anticonvulsants (gabapentin, pregabalin)
Topical analgesics
(capsaicin, lidocaine)
NSAIDs
- type of pain?
- MOA?
- SE?
- nociceptive
- inhibits cyclooxyrgenase so prostaglandin synthesis decreases
-GI irritation/bleeding
renal toxicity
Drug interactions
CV se (Cox-2)
Paracetamol
- effect?
- MOA?
- SE?
- analgesic & antipyretic effect
- inhibition of central prostaglandin synthesis
- liver damage
Opioid analgesics
- effect?
- MOA? (4)
- SE?
-nociceptive, partially effective in neuropathic
-activate endogenous analgesic systems
and stimulate receptors in limbic system to eliminate subjective feeling pain
effect descengin pathways that modulate pain perception
reduce ascending pain signal transmission
- nausea vomiting Constipation Dizziness or vertigo Somnolence sry skin/pruritus
TCAs
- effect?
- MOA?
- Se?
-neuropathic pain
complex regional pain syndrome
Tension headache
-Inhibition of neuronal reuptake of noradrenaline and serotonin
-constipation dry mouth somnolence abnormalities of HR insomnia inc appetite
SSRIs & SNRIs
- effect?
- MOA?
- SE?
-neuropathic pain, SNRIs better
-selectively inhibit reuptake of serotonin, noradrenaline or both
intensify descending inhibition
-nausea & vomiting constipation somnolence dry mouth inc sweating loss of appetite
Anticonvulsants
- effect
- MOA (carbamazepine, gabapentin, pregabalin)
- SE?
-neuropathic
-Gabapentin:
binds to presynaptic voltage-dependent calcium channels1
Pregabalin:
interacts with special N-type calcium channels1
Carbamazepine:
blocks Na+1 and Ca2+ channels
-sedation, dizziness, ataxia, peripheral oedema, nausea, weight gain
Topical analgesics
- examples?
- act where?
- SE?
-Rubefacients
capsaicin
diclofenac, lidocaine
- A delta fibres and C fibres
- rash, pruritus
remember about complimentary therapies
physical therapy: massage etc
relaxation, breathing techniques
CBT
