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Complex regional pain syndrome (CRPS)

Complex regional pain syndrome (CRPS) is severe, persistent pain in a limb after an injury or surgery, out of proportion to the original event, with changes in colour, temperature, swelling or movement. Early diagnosis and active rehabilitation give the greatest chance of improvement, supported by medication and procedures where needed.

After a fracture, a sprain or an operation, pain is expected to settle as tissue heals. In CRPS it does the opposite: pain persists and intensifies out of all proportion to the original injury, and the limb itself changes — colour, temperature, swelling, sweating, skin and nail changes, and increasing difficulty moving it. Touch can become intensely painful. It most often affects a hand or foot, and it is frequently bewildering and frightening for the person it happens to, not least because it is often diagnosed late.

How is it diagnosed? Clinically, against internationally accepted criteria that require a characteristic combination of symptoms and examination findings, after other explanations — infection, nerve compression, vascular problems — have been considered. There is no blood test or scan that confirms CRPS; investigations serve mainly to exclude alternatives. This is one reason assessment by a clinician familiar with the condition matters, in both directions: CRPS is missed in some people and over-diagnosed in others.

What causes it? The mechanisms involve an exaggerated and persistent response of the nervous system, immune system and blood vessels to an injury — the alarm system fails to stand down. Why it happens to some people and not others is not fully understood. It is not imagined, it is not caused by the person, and it does not mean the original injury was mismanaged.

Does it get better? Many people improve substantially, particularly with early, active treatment — and some recover fully. A proportion have persistent symptoms, and honest care means saying so. The practical message from the evidence is that outcomes are better the earlier active treatment starts, which is why early referral is encouraged rather than waiting to see whether it resolves.

What does treatment involve? The core is active rehabilitation of the limb: graded use, desensitisation, and retraining the nervous system's map of the limb through structured approaches with physiotherapy and occupational therapy. Everything else exists to make that work possible. Medication is used to bring pain to a level where the limb can be used. Procedures — including sympathetic nerve blocks — can reduce pain in selected people and are used as enablers of rehabilitation. For severe cases not responding to other measures, supervised inpatient infusion therapy is considered after full assessment, and neuromodulation is an option for a carefully selected minority.

The rehabilitation partnership. Dr Martin's dual training in pain medicine and rehabilitation medicine is directly relevant here: the procedural and rehabilitation plans are made together, with defined goals for the limb, and reviewed against progress. Psychological support is offered where the condition's impact warrants it — a standard part of good CRPS care, not a comment on the pain's reality.

If you suspect CRPS. Ask your GP or surgeon about referral sooner rather than later. Please indicate the concern on the referral — suspected CRPS is triaged with its urgency in mind.

Sources: International Association for the Study of Pain; Healthdirect Australia.