THERMAL GRILL ILLUSION AND COMPLEX REGIONAL PAIN SYNDROME TYPE-I (REFLEX SYMPATHETIC DYSTROPHY)

Background and Objectives. In normal humans, placing a hand on a therm al grill containing warm elements separated by cool ones produces a bu rning sensation. In this case report, responses to a thermal grill in a patient with neuropathic pain were examined. Methods. The responses of a 31-year-old woman with complex regional pain syndrome type I (ref lex sympathetic dystrophy) to a thermal grill were evaluated before an d after stellate ganglion block. Results. The patient experienced a bu rning sensation when the unaffected hand was placed on the grill and c ould distinguish which element was warm and which was cool. An intoler able burning sensation caused the patient to quickly (within 4 seconds ) withdraw the affected hand when it was placed on the grill. Touching cool elements with the affected hand produced an intense burning sens ation (cold allodynia), whereas touching warm elements produced a plea sant warm sensation. Stellate ganglion block with phenol, local anesth etic, and steroid resulted in long-lasting absence of cold allodynia. Conclusion. The thermal grill may be a useful a tool to help understan d the pathophysiology of complex regional pain syndrome type I.