Diagnostic Guidelines for Complex Regional Pain Syndrome

The complex regional pain syndrome, a special form of neuropathic pain, develops after a minor trauma of the distal limbs. Besides the presentation of pain disproportional to the inciting event, further plus and minus symptoms in the form of sensory, vasomotor, sudomotor-oedematous and motor-trophic changes can be found. Interindividually and intraindividually, occurrence of these symptoms differs widely and single symptoms can be lacking completely. A gold standard in diagnosing CRPS has not been found yet, diagnostics are based on the patients medical history and correlating clinical signs. The International Association for the Study of Pain (IASP) compiled and later on revised operational diagnostic criteria resulting in a satisfactory sensitivity and specificity for both research and clinical needs. Additionally, diagnostic tools can support the clinical suspicion - reasonable tests are conventional X-ray examination comparing sides, magnetic resonance imaging and a 3-phase bone scintigraphy. Moreover, electrophysiological examinations can prove a nerve lesion and differentiate between CRPS type I and II. A temperature difference can be detected via infrared thermography. Furthermore, quantitative sensory testing can verify the magnitude of the sensory disturbance and can be beneficial to objectify therapeutic effects. Use of these diagnostic tools, even after achievement of normal findings, cannot exclude a CRPS and the decision for therapeutic initiation should not be influenced thereby.