Study of Proteins Associated With Complex Regional Pain Syndrome

Overview

This study will try to learn more about complex regional pain syndrome, or CRPS (previously known as reflex sympathetic dystrophy, spreading neuralgia, and sympathalgia), by examining the release of small proteins in the blood of patients with this condition. Patients with CRPS usually have three types of symptoms: * Sensory abnormalities increased sensitivity to pain or a painful reaction to a harmless stimulus * Perfusion abnormalities alterations in blood flow, temperature abnormality, swelling, decrease or increased nail growth, and hair and skin changes * Motor abnormalities weakness, guarding (Holding the limb in such a fashion that it minimizes accidental or intentional contact from possible sources of pain), and atrophy (wasting) The cause of CRPS is unknown, and there are no definitive diagnostic tests for the condition. Because early treatment improves the prognosis of CRPS, a test that enables early diagnosis would be important for optimal medical management. The findings of this study may contribute to the development of such a test and possibly new drug treatments. Normal healthy volunteers and patients of any age with complex regional pain syndrome who are in otherwise good general health may be eligible for this study. Participants will have a medical history, physical examination and collection of a blood sample. They will fill out several questionnaires, providing information on their health, personality, mood, pain levels, and symptoms. Participation in the study requires one outpatient clinic visit.

The etiology of Complex Regional Pain Syndrome (CRPS) is unknown but a patient typically presents with a triad of clinical findings: sensory abnormalities, perfusion abnormalities and alterations in motor function. Since some of these findings are seen in the other disease states, the diagnosis is often not clear. A response to a sympathetic ganglion block (stellate or lumbar) is also suggestive of the disorder. However, there is no definitive diagnostic test for CRPS. Experience has shown that early aggressive treatment improves the prognosis. Therefore, tests that facilitate the early diagnosis would have important clinical implications. Advances in laboratory techniques allow analysis of clinical samples to identify protein or patterns of protein changes associated with a disease state. Patients suffering with CRPS who are currently seen in a pain clinic will be asked to participate in this study. The subjects will complete a brief symptom survey, be examined by a co-investigator to document sensory, temperature and trophic changes, and have a blood sample collected for protein and gene expression (RNA) analysis. Blood samples from age-matched controls will be collected from non-CRPS patients. Fifty patient samples collected from each group will be analyzed and used to teach the diagnostic software and an additional 20 samples (10 controls, 10 CRPS patients) will be used to validate diagnostic accuracy.