In keeping with other efforts to raise awareness about CRPS, here’s a great little article from Moseley et al (2013) that represents that rare case of a scientific paper that is easily accessible and provides immediately useful clinical information.
Intense Pain Soon After Wrist Fracture Strongly Predicts Who Will Develop Complex Regional Pain Syndrome: Prospective Cohort Study
“An important finding was that it was possible to obtain predictions that were nearly as accurate as those obtained using the 4-predictor model using just 1 predictor: average pain severity over the last 2 days, assessed in the first week after wrist fracture. This suggests that it may be possible, in clinical practice, to identify most people who will subsequently develop CRPS simply by asking, in the first week after fracture, about the severity of pain experienced over the preceding 2 days. This simple assessment can be carried out in seconds and can be conducted by telephone if needed.
In this population, people with pain intensity equal to or less than 4 are unlikely to develop CRPS, but people with pain scores equal to or greater than 5 are at high risk of developing CRPS.
A pain score equal to or greater than 5 in the first week after fracture should be considered to be a ‘‘red flag’’ for CRPS.”
The complete four-predictor model consisted of the following features:
1. Pain- rated by the subject on a VAS of 0 (no pain at all) to 10 (worst possible pain)
2. Swelling- the circumference of the thumb and first three digits measured by the researchers and expressed as a proportion of the measurements of the unaffected hand.
3. Dysynchiria- the presence of sensation in the affected hand when pinprick and allodynia testing were undertaken on the unaffected hand being viewed in a mirror, with the affected hand hidden. That is, sensation provoked by the illusion of the affected hand being touched.
4. Left/Right Discrimination deficit- tested using in house software (similar to Recognise)
The authors caution readers “not to infer causal relationships between the 4 predictors (pain, reaction time, dysynchiria, and swelling) and the development of CRPS” and that the guidelines must be considered provisional until further validation in other samples.
Predicting the next, obvious, question the authors note that “the best available evidence from high quality randomized trials and systematic reviews suggests that it may be possible to reduce the incidence of CRPS with high-dose vitamin C”.
Using the findings of this well designed and robust (near consecutive sample of 1,549 patients) study, clinical scientists at the coal face, seeing people with high pain ratings soon after wrist fracture, might consider the findings of left/right discrimination deficits and dysynchiria in this population and reason that a left/right discrimination assessment, with a trial of carefully graded left/right discrimination training might be appropriate, followed by explicit motor imagery and sensibly introduced mirror therapy – I would.
PS – Full, open access article at the link above!