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Chronic pain — principles
Chronic pain lasts beyond the time of healing; nociceptive and neuropathic pain are told apart, because in neuropathic pain opioids help little and the first line is amitriptyline, duloxetine, gabapentin or pregabalin.
Why it matters in the exam
The exam asks about the first line in neuropathic pain and the exception — carbamazepine for trigeminal neuralgia; about complex regional pain syndrome (CRPS) and its two types; cancer pain and "breakthrough" doses; phantom pain; and the risk factors for chronic pain after surgery. It also asks about the limited place of opioids in chronic non-cancer pain.
Neuropathic pain comes from damage to the nervous system and is described as burning, shooting or stabbing, sometimes with allodynia — pain from a touch that is normally not painful. CRPS is diagnosed by the Budapest criteria: disproportionate pain with changes in sensation, vasomotor function, sweating and colour, movement and skin; in type 1 there is no defined nerve injury, and in type 2 there is. The main treatment is physiotherapy and function, alongside drugs.
Chronic pain after surgery is especially common after amputation, thoracotomy, mastectomy and hernia repair; the risk factors are severe pain before and after surgery, anxiety and catastrophising, and surgery that damages nerves. In cancer pain a stepwise analgesic ladder is used, a breakthrough dose of about one sixth of the daily opioid dose, and a neurolytic coeliac plexus block in pancreatic cancer. In non-cancer pain long-term opioids give limited benefit and a risk of dependence. Phantom pain after amputation is common and is distinguished from pain in the stump itself; here too the approach combines neuropathic pain drugs, rehabilitation and support.
Key points
- Neuropathic pain: amitriptyline, duloxetine, gabapentin, pregabalin.
- Trigeminal neuralgia: carbamazepine.
- CRPS: Budapest criteria; treatment with physiotherapy.
- Cancer pain: breakthrough dose about one sixth of the daily dose; coeliac block for pancreas.
- Chronic pain after surgery: amputation, thoracotomy, mastectomy, hernia.
Summary table
| Condition | First line | Exam point |
|---|---|---|
| General neuropathic pain | Amitriptyline, duloxetine, gabapentin or pregabalin | Opioids are not first line |
| Trigeminal neuralgia | Carbamazepine | The exception in neuropathic pain |
| Localised neuropathic pain | Lidocaine or capsaicin patch | For example after shingles |
| CRPS | Physiotherapy and function, alongside drugs | Type 1 without nerve injury, type 2 with injury |
| Cancer pain | Stepwise ladder; breakthrough dose about one sixth of the daily dose | Coeliac block in pancreatic cancer |
A free exam question
גירוי של כאב בסוסים נמדד על ידי .טכיקרדיה אם במקביל לגירוי הכואב מופעל לחץ על האף של הסוס, הדבר גורם ?לירידה בטכיקרדיה. לאיזה תופעה הדוגמא מתאימה (the question as examined, in Hebrew)
- א. Stress induced analgesia
- ב. Placebo induced analgesia
- ג. Conditional pain modulation
- ד. Peripheral opioid analgesia
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Sources
- NICE guideline CG173: Neuropathic pain in adults — pharmacological management, 2013, updated 2020 — First-line treatment
- IASP / Budapest criteria for complex regional pain syndrome, 2010 — Diagnostic criteria
- Miller's Anesthesia, 9th edition (2020) — Chronic Pain Management
Sources are given for further reading; the text is written afresh and not copied from them.
Reviewed by the Examqo AI Professor · 2026-11-02. The text may contain errors; when in doubt, check the source.