pain clinical Flashcards
what is pain
unpleasant sensory and emotional experience associated with actual or potential tissue damage
how is pain classified
duration - acute or chronic
mechanism- nociceptive, neuropathic or neoplastic
what is acute pain
sudden onset
resolved by treating cause
<6m
OTC/WHO ladder for treatment
what is chronic pain
gradual onset
usually the result of a condition that is heard to diagnose/treat
>6m duration
musculoskeletal pain
what is nociceptive pain
pain preventing or in response to tissue damage
what is neuropathic pain
malfunction of the nervous system or nerve damage
what is oncoplastic pain
altered nociception in the absence of tissue or nerve damage
what are the 3 rules of the WHO pain ladder
by the clock - as often as possible
by the mouth - unless not possible
by the ladder
what are the steps on the WHO pain ladder
- non-opioid (paracetamol, NSAIDs, COX)
- mild opioid (codeine, dihydrocodeine, tramadol)
- strong opioid (morphine, oxycodone, fentanyl)
what adjuvant therapies can be used for pain
neuropathy - AEDs (gaba, pregab and carba)
- TCAs/SSRIs
palliative bone pain - dexamethasone
non-pharmacolog - physio, exercise, physological treatment, acupuncture
what are opioids used for
acute pain and palliative care
opioid metabolism
CYP2D6 - varies between patients
opioid side s/e
N&V - may settle
constipation - co prescribed w/ laxatives
drowsiness/sedation
resp depression
renal function
addiction
what are the signs of opioid overdose
pinpoint pupils
hypoxia
resp depression
NEWS2
- RR <8
- O2 <85% on air
- tachycardia
- sedation
what are the non-pharmacological interventions for lower back pain and sciatica
- exercise and manual therapies
- psychological activities
- return to work programs
pharmacological treatment for lower back pain
- NSAIDS (GI/renal/age - PPI and stop date)
- weak opioids if NSAID C/I or not tolerated
- paracetmol alone not recommended
pharmacological treatment of sciatica
- no gabapentinoids, AEDs, benzos - stop if on
- limited evidence for NSAIDs
- no opioids
- epidural injections or surgery
how is osteoarthritis treated
- exercise/weight loss
- manual therapies
- oral/topical NSAID
- paracetamol/weak opioids considered
- intraarticular steroids
- joint replacement
how is neuropathic pain treated
- if initial C/I or not tolerated
amitriptyline/duloxetine/gaba/pregab - tramadol only for acute rescue therapy
- capsaicin can be used for local if oral not tolerated
what is palliative care
aim is to improve QoL at end of life
what pain relief is used in palliative care
24 hr simple analgesia or weak opioid
- PRN injection but if >3 then syringe driver
naloxone for toxicity
what is used to treat breathlessness in palliative care
opioid or midazolam
what is PCA
patient controlled analgesia - usually 1mg/ml morphine but if renal function reduced give fentanyl
monitoring for PCA
BP
pulse
RR
sedation
pain score
- hourly for 8
- every 2 for 8-24
- every 48 hours after
PCA s/e
N&V - cyclizine
pruritis - chlorphenamine
RR <8 - O2, monitor and stop - consider naloxone
excess sedation - stop, monitor, non-opioid analgesia
what is an epidural
delivery of analgesics with or without adjuvants o epidural space
where are epidurals given
epidural space
epidural space physiology
dorsal route ganglion - cell bodies from afferent and efferent nerves, communication between peripheral and central nervous systems
- Spinal meninges - dura mater is outer layer (arachnoid mater and then pia mater) - tough and strong to protect the spine
○ Subarachnoid space - space between the subarachnoid mater and the pia mater - filled with CSF, accessed for lumbar punctures
○ Epidural space between dura mater and bone - fatty matter and space for epidural to be injected
what are the components of epidural
opioid analgesic
- inhibits pain transmission at spinal cord
- reversible, no migration
anaesthetic
- diffuses across myelin sheath into nerve
- inhibits sodium channel preventing depolarisation
ephedrine for hypotension
naloxone
cyclizine for sickness
what are the advantages of epidural
- better relief for smaller doses
- reduced DVT incidence
- less sedation
- covers post-op
- improved pulmonary function
- reduced cardiac and sepsis issues
what are the disadvantages of epidural
- Accidental injection into spinal cord - total spine block
- Risk of permanent damage
- Accidental IV administration
- Dural puncture headache
- Epidural bleed
- Drug migration can lead to respiratory paralysis
- Infection risk
- Requires informed consent
s/e of epidural
- resp arrest (C3-C5)
- resp depression
- hypotension/hypothermia
- reduced cardiac output
- reflex tachycardia
- overdose/IV - myocardial depression
- reduced hepatic/real perfusion
- dural headache
- tinnitus
- pruritis
- N&V
- sedation
what rescue therapies are used for epidurals
- IV bupivacaine - reverse cardiac arrest or toxicity
- opioid toxicity - naloxone
- hypotension - ephedrine
- dural puncture headache - CSF leakage causes drop in pressure
C/I for epidurals
- Refusal
- Infection at site
- Clotting abnormalities
- Severe respiratory impairment
- Uncorrected hypovolaemia
- Raised intracranial pressure
- Neurological disease
- Injury or deformity changing anatomy
- Tattoos - site of injection would be up to clinician (could cause ink leakage/bleeding)
what is a tension headache
most common form, thought to be due to neck/scalp muscle spasm - can be due to stress
symptoms of a tension headache
mild to moderate pain
non-throbbing and vice like
unilateral
may worsen throughout the day
what is a cluster headache
sudden onset lasting 10m to 3hr
what are the symptoms of a cluster headache
- Excruciating- severe pain on one side of the head
- Nasal or eye symptoms
- Accompanied by red eye, lacrimation, nasal congestion, rhinorrhoea, facial sweating, miosis, droopy eye lids and eye lid oedema
what are the differential diagnosis for cluster headaches
meningitis - non blanching rash, light sensitivity
bleeding - trauma, confusion
cranial arteritis - pre-existing joint issues
what are medication overuse headaches
Pain is oppressive - worse in morning caused by painkiller overuse
how are medication use headaches treated
stop therapy
pain gets worse before it gets better
gp for prophylaxis
what medications put patients at risk of medication overuse headaches
using analgesics or triptans for more than 15 days/month
how should painkillers be used for headaches
<15 days a month
3-4 doses / 2 days
no consecutive use
avoid codeine
what are the symptoms of migraines
prodrome - pre-headache
- aura
headache
- lateralised and pulsing
- N&V
- dislike for bright light and loud noises
what are the theories for pathophysiology of migraines
- vascular theory - disproven
- brain hypothesis - increased extracellular potassium causing decreased flow and neuronal inhibition
- inflammation - activation of trigeminal nerve
5HT implicated in pathogenesis - metabolites present in urine
what are the three types of migraine
classical
common
abdominal
what are the symptoms of a classical migraine
aura
slurred speech
visual phenomena
what are the symptoms of common migraines
no aura
what are the symptoms of abdominal auras
usually in children
headaches
GI symptoms
withdrawing from play
not liking loud noises
cyclic
what are some trigger factors of migraines
certain foods
hormonal changes
environmental issues
change in standard routine
how are migraines diagnosed
repeated attacks lasting 4-74 hours with at least TWO
- unilateral pain
- throbbing pain
- aggravated by movement
- moderate or severe intensity
and ONE
- nausea and vomiting
- phono/photophobia
which migraine patients need to be referred to GP
> 24 hrs
no nausea but vomiting in the morning
unsteadiness
under 12s
suspected ADRs
how are migraines managed
elimination of triggers
acute intervention for breakthrough
if >4/month offer prophylaxis
what is the acute treatment of migraines
- dispersible or effervescent ibuprofen 400, aspirin 900 or paracetamol 1g
- OTC prochlorperazine or triptans
what are the triptans
5HT1B and 1D agonists
C/I in IHD, HT, 65 +
s/e dizziness, tiredness, tight chest and throat
1 tab - 2nd dose if goes away ad comes back
which medications can be used for migraine prophylaxis
beta blockers
pizotifen
methysergide
TCAs
topiramate
valproate
beat blockers s/e
fatigue
bronchoconstriction
cold extremities
what is methysergide and its s/e
5HT antagonist
N&V
rare fibrotic conditions
what is pizotifen and its s/e
5HT agonist
weight gain
sedation
what issue needs to be accounted for when using valproate and topiramate for migraines
teratogenic
what are the trigger factors for migraines and how to reduce them
anxiety - coping strategies
change of habits - reversal to normal
foods - exclude
bright lights and noise - avoid
strenuous exercise - avoid
when is migraine prophylaxis indicated
- functional impairment
- > 2 headaches a week
- patient compliance
