Temperature difference between the affected and unaffected limbs in complex regional pain syndrome.

ABSTRACT

Background: Complex regional pain syndrome (CRPS) is classified into two subtypes based on clinical presentation warm or cold.Methods: We examined the distribution of warm and cold subtypes in CRPS patients before they received lumbar sympathetic block. We retrospectively analyzed 81 prelumbar sympathetic block Forward Looking InfraRed images obtained from 30 patients to study temperature asymmetry between affected and unaffected limbs.Results: In 23 of the 30 patients (77%), the temperature difference between the affected and affected limbs was within the normal range (<0.6°C difference). Of the remaining seven cases, six (20%) were diagnosed with cold-CRPS and one (3%) with warm-CRPS. During subsequent interventions, 74% of the patients maintained a temperature difference within the normal range (<0.6°C difference).Conclusion: Retrospective analysis of Forward Looking InfraRed thermal camera images in CRPS patients showed that 77% of patients did not exhibit significant temperature asymmetry (<0.6°C difference) between affected and unaffected limbs.

What is the article about? The article discusses a condition called complex regional pain syndrome (CRPS), a type of chronic pain that affects arms or legs. CRPS can potentially make the affected limb colder or warmer compared with the other limb. This study investigated temperature differences between the affected and nonaffected limbs in CRPS patients to be treated with a procedure called lumbar sympathetic nerve blocks. Researchers used an infrared thermal camera to take pictures of the patients' feet to measure these temperature differences.What were the results? The study found that 77% of the patients, who were about to have their initial nerve block treatments, did not show a significant (greater than 0.6°C) temperature difference between their affected and nonaffected limbs.What do the results mean? The study suggests that most CRPS patients demonstrated only a small temperature difference between their affected and nonaffected limbs. This result is different from earlier studies, which suggested that warm CRPS occurs in about 70% and cold CRPS in about 30% of cases at the time of diagnosis.