Cocaine-induced reflex sympathetic dystrophy

Reflex sympathetic dystrophy (RSD) usually follows traumatic injuries or ne urologic disorders. The authors report a rare case of RSD that followed int raarterial administration of cocaine in a patient with a history of intrave nous drug abuse. The cocaine was self-administered inadvertently into the f emoral artery rather than the femoral vein. Despite the intense pain, swell ing, and dermatologic changes that followed, the diagnosis of RSD was not c onsidered until scintigraphic studies suggested it. A combination of normal radiographs, a normal leukocyte study, and an abnormal bone scan in the re gion of tenderness and swelling excluded other possibilities and suggested RSD. In our patient, RSD was likely caused by an ischemic autonomic injury from the vasoconstrictor action of cocaine. Clinical follow-up and relief u sing phentolamine, an alpha -adrenergic blocker and vasodilator, made the d iagnosis of RSD most likely.