Pain clinical Flashcards
(42 cards)
How can you measure pain?
Pain scales:
- Visual scale (VAS)- pointing
- Numerical rating scale (NRS)- Rate from 0-10
- Use facial expressions charts (good in younger patients)
Examinations:
colour changes
swelling
asymmetry
tenderness
range of movement
weakness
Compare acute and chronic pain.
Acute:
- sudden
- Treated by resolving cause
- Usually due to trauma/injury/surgery
- Lasts <6months
- OTC or WHO pain ladder
Chronic:
- Gradual
- Usually result of condition difficulty to treat
- >6months
- Hard to find lasting releif
- Often movement and physio helps (in acute, usually just rest)
- Can have social and psychological factors
- 7 x more likely to leave job
What are the different types of pain?
- Nociceptive pain
- Neuropathic pain
- Nociplastic pain
What is nociceptive pain?
This is the ability to detect a painful stimulus via nociceptors e.g. reflex when touching something hot
- prevents tissue damage and occurs in response to tissue damage
What is neuropathic pain?
Malfunction in the nervous system or damage to nerves e.g. diabetic neuropathy
- usually described as a burning electrical shock sensation/shooting pain
What is nociplastic pain?
Altered nociceptionin body in the absence of nerve or tissue damage.
- Causes widespread intense pain e.g. fibromyalgia
- Management is exercise, physiological non-pharmacological management e.g. physio, accupuncture
Describe the stages of the WHO pain ladder
- Non-opiod
e.g.
Paracetamol ( check weight, liver function)
NSAIDs- consider renal function,GI- co-prescibe gastric protection e.g. PPI
Topical preparations e.g. NSAID gel, lidocaine, capsaicin - If pain persists or increases:
Mild opioid- as an alternative or addition to the above
e.g.
Codeine
Dihydrocodeine
Tramadol
- have limited potency at mu opioid receptors - if pain persists or increases
Strong opioids for moderate/severe pain
e.g.
Morphine
Diamorphine
Oxycodone
- These have strong potency at the mu receptor
NOTE- these should REPLACE mild opioids and not added to them
And Adjuvants throughout:
- Anti-epileptics- mainly for neuropathic pain e.g. Gabapentin, Pregablin, Carbamazepine (Carbamazepine I used in trigeminal myalgia)
- Anti-depressants- mainly for neuropathic pain e.g. Amitriptyline, SSRIs, Trycyclics
- Dexamethasone- bone pain in palliative care or oncology
- Non-pharmaceutical (ideal): physio, exercise, psychological therapies, acupuncture
What are examples of adjuvants that may be used alongside the WHO pain ladder?
- Anti-epileptics- mainly for neuropathic pain e.g. Gabapentin, Pregablin, Carbamazepine (Carbamazepine I used in trigeminal myalgia)
- Anti-depressants- mainly for neuropathic pain e.g. Amitriptyline, SSRIs, Trycyclics
- Dexamethasone- bone pain in palliative care or oncology
- Non-pharmaceutical (ideal): physio, exercise, psychological therapies, acupuncture
What drugs have limited efficacy in long term pain?
Opioids- if don’t achieve useful pain relief in 2-4 weeks, unlikely to gain long term benefit.
What types of pain are opioids not indicated for?
Widespread
back pain
headaches
What is the risk concerning metabolism of weak opioids?
Weak opioids have a low affinity for mu-receptors and they are partially metabolised in the liver via CYP 2D6 ( a cyp450) to morphine (codeine-> morphine).
- There is an inter patient variability on this metabolism dependent on gene expression- metabolism is impacted by expression of this CYP enzyme.
- Some patients are ‘Super metabolised’ meaning they are good metabolisers. Note if breastfeeding, super-metabolisers are more likely to pass through to baby as mum is metabolising more codeine to morphine
- = unpredictable variation in efficacy and toxicity
Also risks:
- In impaired renal function- opioids are highly renal excreted
- Monitor dependence/addiction
What are possible side effects of opioids?
- N+V
- Constipation- often co-prescribe laxatives- a stimulant and osmotic (e.g. Senna and Laxido)- NOT Bulk laxatives
- drowsiness
- sedation
- respiratory depression
What laxatives are often co-prescribed with opioids?
Constipation- often co-prescribe laxatives- a stimulant and osmotic (e.g. Senna and Laxido)- NOT Bulk laxatives
What are the signs of opioid overdose/toxicity?
- Stimulation of the PNS:
pinpoint pupils- less/no response to light shined to the eye - Hypoxia- lox O2- blue lips, pale skin
- Respiratory depression- activation of mu-opioid receptors un brainstem (pre-Bötzinger complex) that help coordinate the respiratory rhythm, opioids binding = decreases ability to coordinate rhythm:
Resp rate < 8bpm
O2 saturation <85%
tachycardia
High sedation score
BP can be high or low
unconsciousness, raspy breath, snoring, shallow or slow breathing
How do you manage lower back pain?
1.6 million adults in the uk have back pain for >3 months
Non-pharmacological:
- Exercise programmes and manual therapies e.g. massages
- Psychological therapies e.g. CBT
- return to work programmes
Pharmacological;
- NSAIDs- caution in at-risk groups e.g. GI issues, renal, age. add PPI
- Weak opioid if NSAID Cid/ineffective
- Not paracetamol alone0 efficacy is ineffective
How do you reverse opioid-induced respiratory depression/ opioid toxicity?
Opioid-induced respiratory depression is potentially fatal but may be reversed by the opioid receptor antagonist naloxone
What is and how do you manage sciatica?
Sciatica is shooting pain down the leg.
- Is leg pain secondary to lumbosacral nerve root pathology- due to compression or irritation of the sciatic nerve in the Lower spine.
Non-pharmacological: (main)
- Exercise programmes and manual therapies e.g. massages
- Psychological therapies e.g. CBT
- return to work programmes
Pharmacological:
- No gabapentinoids, anti-epileptics benzodiazepines (If already prescribed, discuss withdrawal)
- NSAIDs- have limited benefit
- No opioids for chronic sciatica
- epidural injections- corticosteroids and local anaesthetic
- spinal decompression surgery
- paracetamol is unlikely to help
What are the management options for osteoarthritis?
Osteoarthritis is the breakdown of cartilage in joints- pain, tenderness, swelling, grating
Treatments
- Exercise- physio
- Weight loss- decreases the pressure on the joints
- Manual therapies
- Topical NSAID
- May consider paracetamol or weak opioids
- intra-articular corticosteroid injections
- joint replacements
What drugs may be used for neuropathic pain?
4 drugs used:
- Amitriptyline
- Duloxetine
- Gabapentin
- Pregablin
Try 1, if not effective, try another
- Consider tramadol only if acute rescue therapy is needed
Also,
- Capsaicin cream for localised pain (made from chilli peppers- may cause burning or stinging on application- this is normal)
- Carbamazepine- used in trigeminal neuralgia
Do you follow the WHO ladder in palliative care?
Adapted WHO ladders- often skip to strong opioids
Requires individualised and holistic care
Discuss pain relief in palliative care.
Aim is to increase the quality of life for patients and their families.
- Give 24 hour pain relief- with simple analgesia or string opioid
- No max opioid dose
- Begin with anticipatory PRN injection: The choice depends on the patients renal function
Morphine SC 2.5-5mg 2-4 hourly (eGFR >60)
Oxycodone SC 1.25-2.5mg 2-4 hourly (30-60)
Alfentanil SC 125-250 mcd 2-4 hourly (<30)
If the patient needs ~ 3 of these injections in a 24 hour period, they should be switched to a syringe driver.
- if worried about toxicity e.g. following a dose increase, give Naloxone.
Syringe driver:
- 24 hr continuous sc infusion
- need a diluent for volume e.g. NaCl, water for injection
- can also use to deliver other drugs e.g. Buscopan, drugs for nausea/agitation
What factors are considered when choosing an analgesic for post-op pain?
Patient factors:
- Co-morbidities
- Renal/liver clearance abilities
- Age- sedation, falls, dizziness risk
- Frailty
- Allergies
Patient discussion:
- Risks and benefits
- Duration anf fischarge pains
- consider any pain-relief they’re on pre-op
When can NSAIDs not be used for post-op pain?
if patient has has a hip or pelvis sugeries- they affect the bone recovery
When are oral opioids used or not used in post-op pain?
- Used in moderate-severe pain e.g. in large or more complex procedure e.g. gastro or orthopaedic operation
- Don’t use if have PCA or opiate epidural infusion- only 1 route at a time. However, patients on Buprenorphine to fentanyl patches prior to admission are often continued alongside PO
- they aid recover- allow patients to mobilise, return of cough reflex- getting patients moving asap increases prognosis
