essential pain management Flashcards
what is pain
an unpleasant sensory and emotional experience associated with or resembling that associated with acute or potential tissue damage or described in terms of such damage
benefits of treating pain: physical
improved sleep
better appetite
fewer medical complications
better mobility
benefits of treating pain: psychological
reduced suffering
less depression, anxiety
benefits of treating pain: for society
lower health costs e.g. shorter hospital stay
able to contribute to community
classification of pain: acute pain
recent onset, probable limited duration
classification of pain: chronic pain
> 3 months
often no identifiable cause
classification of pain: cancer pain
progressive
may be mixture of acute and chronic
classification of pain: nociceptive pain
obvious tissue injury or illness
aka physiological or inflammatory pain
protective function
classification of pain: neuropathic pain
nervous system damage or abnormality
does not have protective function - pain ongoing after original injury (if there has been one)
pain physiology: periphery
tissue injury that results in release of chemicals - prostaglandins, substance p
stimulation of nociceptors
signals travel in A-delta or C fibres to spinal cord (dorsal root ganglion)
pain physiology: spinal cord
dorsal horn is first relay station
second nerve travels up opposite site of spinal cord into thalamus
pain physiology: brain
thalamus is second relay station
connections to many parts of brain - cortex, limbic system, brainstem
pain perception occurs in cortex
pain physiology: modulation
descending pathway from brain to dorsal horn
usually decreases pain signal - neurotransmitters
neuropathic pain pathological mechanisms
increased receptor numbers - enhance pain signal and keeps it going
abnormal sensitisation of nerves - peripheral, central
chemical changes in dorsal horn
loss of normal inhibitory modulation
simple analgesics
paracetamol (acetaminophen)
NSAIDs - ibuprofen, diclofenac
opioids
weak: codeine, tramadol
strong: morphine, oxycofone, fentanyl
potential for addiction
treatments: periphery
non-drug: rest, ice, elevation
NSAIDs - reduce amount of prostaglandins
local anaesthetics - reduce nociceptive afferent triggering
treatments: spinal cord
non-drug: acupuncture, massage, TENS
local anaesthetics: epidural, nerve blockade
opioids
ketamine (modulates pain signal in descending pathways)
treatments; brain
non-drug: psychological
drug: paracetamol opioids amitriptyline clonidine
paracetamol: advantages
cheap, safe
can be given orally, rectally or IV
good for mild pain (itself) or mod-severe (used w other drugs)
paracetamol: disadvantages
liver damage in overdose
max dose related to patient weight
NSAIDs advantages
cheap, gen safe
good for nociceptive pain
NSAIDs disadvantages
GI and renal (reduced renal blood flow) side effects plus bronchospasm in some patients with asthma
codeine advantages
cheap
sage
good for mild-moderate acute nociceptive pain
codeine disadvantages
constipation
not good for neuropathic pain
tramadol advantages
less respiratory depression
can be used with opioids and simple analgesics
less constipating
tramadol disadvantages
nausea + vomiting
controlled drug
morphine advantages
cheap, generally safe
can be given orally, IV, IM, SC, PR, intrathecally
effective if given regulaly
morphine disadvantages
constipation
resp depression in high dose
controlled drug
addiction/avoidance due to fear of addiction
amitriptyline advantages
cheap, safe in low dose
good for neuropathic pain
also treats depression, poor sleep
amitriptyline disadvantages
anti-cholinergic side effects (e.g. glaucoma, urinary retention)
long term use may be linked with cognitive decline and dementia
pain assessment
verbal rating score numerical rating score visual analogue scale smiling faces abbey pain scale (for confused patients) functional assessments
WHO pain ladder: step one
non-opioids - NSAIDs or paracetamol
WHO pain ladder: step 2
mild opioids (e.g. codeine) with or without non-opioids
WHO pain ladder: step 3
strong opioids (e.g. morphine) with or without non-opioids
WHO pain ladder: mild pain
bottom rung of ladder
WHO pain ladder: moderate pain
bottom and middle rungs
WHO pain ladder: severe pain
bottom and top rungs
WHO pain ladder: as pain resolves
move from top to middle rung
continue bottom rung
lastly,, stop NSAIDs first then paracetamol
RAT approach to pain management
recognise pain
assess pain - severity, type, other factors
treat - non-drug, drugs
drugs for neuropathic pain
amitryptiline
gabapentin
duloxetine
