Prevalence of adverse reactions to radiopaque contrast reported by patients presenting for interventional pain procedure.

Introduction: Adverse reactions to radiopaque contrast media (RCM) are well documented with a wide range of incidences reported. The objective of this study was to determine how many patients in a sample of 200 who presents for interventional pain treatments report a history of adverse reactions to RCM.

Methods: Data from 200 outpatients were collected using a self-administered questionnaire. The questionnaire was designed to obtain information about prior exposure to RCM and any adverse events plus other general information about allergic reactions including known risk factors for allergic reactions. Demographic data and information about past medical history were obtained from each patient.

Results: Of the 200 patients surveyed, 16 reported having had an allergic reaction to RCM. The events met criteria for immediate hypersensitivity reaction. Chemotoxic reactions cannot be ruled out. Of factors associated with risk of allergic reaction, none were clearly more prevalent in subjects reporting an allergic reaction vs. subjects who did not. Atopic patients generally considered susceptible to contrast allergy reported no hypersensitivity reaction. The number of medications and foods the subjects reported caused them to have allergic reactions was extensive.

Conclusion: Patients with a history suggestive of an immediate hypersensitivity reaction to RCM may report for interventional pain procedures normally performed with RCM. Patients who have experienced an immediate hypersensitivity reaction to RCM have increased risk for another reaction if injected again with contrast agent. Therefore, facilities should be prepared to implement measures to prevent recurrent reactions.