19.5 Palliative Symptom Control, Psychological Aspects of Pain and Multidisciplinary Pain Management
Key Takeaways
The biopsychosocial model explains chronic pain as an interaction of tissue factors, thoughts, emotions and social context; catastrophising and fear-avoidance beliefs predict disability more strongly than imaging findings.
Multidisciplinary pain management programmes combine cognitive behavioural or acceptance-based therapy, graded activity and pacing, education and medication review, and aim to improve function rather than eliminate pain.
Long-term opioids give little benefit in chronic non-cancer pain, and the risk of harm rises substantially above about 120 mg oral morphine equivalent per day without additional benefit (Faculty of Pain Medicine guidance).
For conversion in palliative care, oral morphine is roughly twice as potent by the subcutaneous route (divide the oral dose by about 2), and oral oxycodone is about 1.5-2 times as potent as oral morphine.
Noisy respiratory secretions at the end of life can be reduced with antimuscarinics such as glycopyrronium or hyoscine butylbromide, and terminal agitation is commonly treated with subcutaneous midazolam after reversible causes are considered.
19.5 Palliative Symptom Control, Psychological Aspects of Pain and Multidisciplinary Pain Management
The Biopsychosocial Model of Pain
Pain is defined by the International Association for the Study of Pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage" (2020 revision). Chronic pain (lasting more than 3 months) is best understood through the biopsychosocial model:
| Domain | Examples |
|---|---|
| Biological | Tissue injury, nerve damage, central sensitisation, sleep disturbance |
| Psychological | Catastrophising, fear-avoidance, low mood, anxiety, low self-efficacy, past trauma |
| Social | Work and financial stress, family responses, litigation, cultural beliefs |
Central sensitisation and changes in descending modulation mean that pain can persist after tissue healing. The degree of tissue damage often correlates poorly with pain and disability.
Psychological Factors
- Catastrophising: exaggerated negative thinking about pain (rumination, magnification, helplessness) predicts higher pain, more opioid use and worse outcomes, including after surgery.
- Fear-avoidance: fear of pain or reinjury leads to avoidance of activity, deconditioning and disability, which reinforce pain.
- Depression and anxiety are common and bidirectionally linked with chronic pain.
- "Yellow flags" in back pain are psychosocial factors that predict long-term disability (for example belief that pain is harmful, low mood, passive coping, social withdrawal).
- Placebo and nocebo effects: expectations change pain. Negative wording ("this will hurt a lot") increases pain through nocebo mechanisms, so careful communication during procedures matters.
Chronic Postsurgical Pain
About 10% of patients develop persistent pain after surgery, with higher rates after amputation, thoracotomy, mastectomy and hernia repair. Risk factors include severe acute postoperative pain, preoperative pain, psychological vulnerability (anxiety, catastrophising) and nerve injury. Good acute pain control and nerve-sparing surgical techniques may reduce the risk.
Multidisciplinary Pain Management
Pain management programmes (PMPs) involve psychologists, physiotherapists, nurses, occupational therapists and physicians. Components include:
- Cognitive behavioural therapy (CBT): identifying and changing unhelpful thoughts and behaviours.
- Acceptance and commitment therapy (ACT): accepting pain while pursuing valued activities.
- Graded activity and pacing: gradual increases in activity rather than cycles of overactivity and rest.
- Education: explaining pain neuroscience, reducing fear.
- Medication review: rationalising and often reducing opioids and other drugs.
- Return to work and social goals.
The aim is better function and quality of life, not necessarily lower pain scores. Interventional procedures (radiofrequency denervation, spinal cord stimulation) are most effective when combined with rehabilitation in selected patients.
Long-Term Opioid Therapy in Non-Cancer Pain
- Evidence for long-term benefit is weak; tolerance, hyperalgesia, endocrine suppression (hypogonadism), immunosuppression, falls, dependence and overdose are significant harms.
- UK Faculty of Pain Medicine guidance (Opioids Aware) states that the risk of harm increases substantially above about 120 mg oral morphine equivalent per day with no increase in benefit.
- Agree goals and a trial period, review regularly, and taper opioids that do not deliver meaningful functional benefit.
- Opioid-induced hyperalgesia (increasing pain with increasing doses) may improve with dose reduction.
- For surgery in opioid-tolerant patients: continue the baseline opioid, use multimodal analgesia (ketamine, regional techniques), expect higher requirements, and plan the postoperative taper.
- Buprenorphine patients can usually continue their usual dose perioperatively, with additional full agonists as needed.
Palliative and End-of-Life Symptom Control
Pain
Cancer pain follows the WHO analgesic ladder principles: by the mouth, by the clock, by the ladder, and for the individual, with adjuvants (corticosteroids for liver capsule or nerve compression pain, gabapentinoids for neuropathic pain, bisphosphonates and radiotherapy for bone pain).
| Conversion (approximate) | Ratio |
|---|---|
| Oral morphine to subcutaneous morphine | Divide by about 2 |
| Oral morphine to oral oxycodone | Divide by about 1.5-2 |
| Oral oxycodone to subcutaneous oxycodone | Divide by about 1.5-2 |
| Oral morphine 24-hour dose to transdermal fentanyl | About 60-90 mg/day oral morphine corresponds to fentanyl 25 (product tables vary) |
- Breakthrough doses are usually about one-sixth of the 24-hour regular dose.
- When switching between opioids, reduce the calculated dose by about 25-50% because of incomplete cross-tolerance.
- In renal impairment, avoid accumulation of morphine metabolites; oxycodone in reduced doses, fentanyl or alfentanil are alternatives.
- Methadone conversion is non-linear and should be specialist-led.
Subcutaneous Infusions (Syringe Drivers)
Continuous subcutaneous infusions over 24 hours are used when oral intake is not possible. Common drugs include opioids, midazolam, levomepromazine, haloperidol, glycopyrronium and hyoscine butylbromide; compatibility of mixtures must be checked.
Other Symptoms
| Symptom | Common management |
|---|---|
| Breathlessness | Treat reversible causes; fan and positioning; low-dose opioids reduce the sensation of breathlessness; benzodiazepines for associated anxiety |
| Nausea and vomiting | Choose by cause: haloperidol (chemical or metabolic), metoclopramide (gastric stasis, avoid in bowel obstruction with colic), cyclizine (raised intracranial pressure or vestibular), levomepromazine (broad spectrum) |
| Malignant bowel obstruction | Hyoscine butylbromide or octreotide to reduce secretions; dexamethasone; venting gastrostomy |
| Noisy respiratory secretions | Repositioning; antimuscarinics (glycopyrronium, hyoscine butylbromide) |
| Terminal agitation | Exclude urinary retention, pain, hypoxia, drugs; midazolam; levomepromazine or haloperidol |
Ethical Principles
- The doctrine of double effect: giving drugs to relieve suffering is ethical even if death may be hastened as a foreseen but unintended effect, provided the intention is symptom relief and the doses are proportionate.
- Advance care planning and documented decisions about resuscitation and escalation should be discussed with patients and families.
- Withdrawing life-sustaining treatment in intensive care should be accompanied by proactive symptom control.
A patient with chronic low back pain has normal neurology but high catastrophising scores, avoids walking for fear of damage, and has been off work for 9 months. Which approach is most likely to improve function?
Escalating oral morphine until pain scores fall below 3 out of 10
Strict bed rest until the pain resolves
Repeat MRI scans to reassure the patient that nothing serious has been missed in the spine
A multidisciplinary programme with CBT, graded activity and education
A patient in palliative care takes modified-release oral morphine 60 mg twice daily and can no longer swallow. What is a reasonable equivalent 24-hour subcutaneous morphine dose?
About 240 mg, because the subcutaneous route is less effective
About 60 mg, because the subcutaneous route is about twice as potent
About 120 mg, because the routes are equivalent
About 10 mg, because subcutaneous morphine is ten times as potent as oral morphine
A dying patient has noisy respiratory secretions that distress the family. Which drug is appropriate?
Glycopyrronium or hyoscine butylbromide subcutaneously
Furosemide 80 mg intravenously
Neostigmine to improve cough strength
Naloxone to reverse opioid-induced bronchial secretions
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