What causes CRPS and what is its prognosis?

What causes CRPS? In almost all cases CRPS is triggered by a trauma to a distal limb.

There may be two types of this condition (a) or (b) as described below, which initially look the same.

(a) About 80% of patients have a good prognosis. Their condition will get better. Appropriate exercising helps to i) reduce CRPS severity, ii) shorten the duration of this type of CRPS, iii) minimise residual problems, and iv) when applied very early after a trauma may prevent this type of CRPS from occurring.

This type of CRPS may be contributed to by inflammation in the affected limb. Appropriate exercising probably works by calming this overactive immune system. Most of these patients will have less pain by 6 months after their CRPS trigger-trauma. For those patients whose pain is not better by 18 months following injury the pain will likely further persist, see below.

(b) In about 20% of patients the pain will persist. This means that their pain does not get much better, whatever we/ they do. These patients will need appropriate exercise advice so that they can regain and maintain their function despite ongoing pain.

Recent evidence suggests that in these patients an autoimmune reaction may cause the condition.

For clarity CRPS “Type 1” or “Type 2” in the literature refers to CRPS without damage to major nerve (Type 1) or with damage to such a nerve (Type 2, this is rare). Recent research has shown that this classification does not contribute much to scientific understanding or clinical practice, and management of these two “Types” is quite similar. This is different from those two types (a) and (b) discussed above.