Complex regional pain syndrome (CRPS) is also known as reflex sympathetic dystrophy, Sudek’s atrophy, shoulder-hand syndrome or fracture disease. It consists of disproportionate, debilitating pain in a limb (usually but not always following trauma), associated with neuropathic changes. It usually starts within a month of the trigger injury, if there is one, and in some cases can spread to adjacent areas/other limbs. The cause is unknown. The Budapest criteria for diagnosis are:
- Continuing pain disproportionate to any inciting event
- At least one sign in at least two of the categories
- At least one symptom in at least three of the categories
- No other diagnosis can better explain, blah, blah
Categories: sensory, vasomotor, sudomotor, motor/trophic.
- Sensory symptoms: Allodynia (pain from non-painful stimulus such as light touch, pressure, or movement), hyperalgesia
- Vasomotor signs/symptoms: Temperature asymmetry >1 deg C, skin colour asymmetry or changes
- Sudomotor signs/symptoms: Oedema, sweating/asymmetry
- Motor/trophic signs/symptoms: Decreased range of motion, motor dysfunction (weakness, tremor, dystonia), changes to hair/nails/skin
Patients can also describe the limb as ‘feeling strange’ not part of their body, or bigger/smaller than the other side.
Prompt treatment of CRPS is advisable and all suspected cases should be referred to a pain clinic. Prognosis is mixed – while 85% of cases have improved or resolved within 18 months (and the associated signs tend to improve even if the pain persists), 50% of all patients remain unable to work because of residual problems. Psychosocial factors can affect speed of recovery, but do not affect the chance of developing CRPS in the first place.
Evidence base for treatment is poor. Possible treatments while awaiting pain clinic appt include:
- Explanation (Appendix 5 of the RCGP CRPS guidelines apparently has a good patient leaflet, but I can’t link to it right now as their site’s down)
- Advice on pacing, goal-setting, and relaxation
- Simple painkillers, with neuropathic treatments if painkillers not working in 2 – 4 weeks
- Desensitisation techniques (see below)
- Encourage gentle movement of the limb and active lifestyle
- Specialist physiotherapy if available (warn patient that this may increase pain short-term but is associated with improved recovery)
- CBT and management of any associated anxiety/depression.
- Educate patients about pain flares – these are common and do not mean that the condition is getting worse. They resolve within days or weeks and activity should be continued during them (it may be necessary to decrease the intensity of physical therapy, but not the frequency).
Desensitisation: this is a method of re-educating the sensory system. Use items with different textures, both rough and smooth (silk, velvet, toweling, scouring pads, Velcro, soft brushes, etc.) and spend a few minutes touching each texture to an unaffected part of the body and concentrating on how it feels. Then touch it to the affected part while concentrating on the memory of how it felt while touching the normal part. Use different movements (stroking, tapping, circular movements). Do this for a couple of minutes at a time as often as possible throughout the day, and also look for opportunities to do it during normal day-to-day activities (with the washcloth while washing, with the bedsheet when in bed, etc.)
(Pulse Learning module – Hot Topics in Pain Control)