Department of Anesthesiology, subdivision Pain Treatment Center, Erasmus MC Rotterdam, The Netherlands.

Increased endothelin-1 and diminished nitric oxide levels in blister fluid of patients with intermediate cold type complex regional pain syndrome type-1.

Background: In complex regional pain syndrome type 1, pro-inflammatory mediators and vascular changes play an important role in the sustained development and outcome of the disease. The aim of this stuldy was to determine the involvement of vasoactive substances endothelin (ET-1) and nitric oxide (NO) during early chronic crps-1.

Method: Included were 29 patients with crps 1 who were diagnosed during the acute stage of their disease and observed during follow-up visits. Disease activity and impairment were determined and artificial suction blisters were made on the crps-1 and the contralateral extremities for measurements of IL-6 , TNF-alpha, ET-1 and nitric oxide.

Results: The levels of IL-6, TNF-alpha and ET-1 in blister fluid in the crps extremity versus the contralateral extremity were significantly increased and correlated with each other, whereas nitric oxide levels were decreased.

Conclusion: The nitric oxide and ET-1 ratio appears to be disturbed in the intermediate stage of crps resulting in vasoconstriction and consequently in a diminished tissue blood distribution. another on the way, jen