1. 2012;15;E665-E675Radiocontrast Media Allergic Reactions and Interventional Pain Practice - A Review
   Literature Review
   Ami Mehra, MD, Jordan L. Newmark, MD, and Aneesh Kumar Singla, MD, MPH.

BACKGROUND: Millions of interventional pain procedures are performed each year in the United States. Interventional pain physicians commonly administer radiocontrast media (RCM) under fluoroscopy for these procedures. However, RCM can cause various types of hypersensitivity or allergic type reactions, in an acute or delayed fashion. Furthermore, some patients report a prior history of hypersensitivity reactions to RCM when presenting to the interventional pain clinic. Both scenarios present challenges to the interventional pain physician.

OBJECTIVE: To describe the various types of hypersensitivity reactions to RCM, as well as strategies to prevent and manage these reactions, within the context of interventional pain practice.

METHOD: A review of the literature from 1975 through 2011 regarding allergic type reactions to RCM, as well as iodine, and shellfish allergy, was undertaken in an effort to review and develop recommendations on managing these patients presenting to the interventional pain clinic.  Keywords used in the literature search were: radiocontrast media, contrast allergy, contrast reaction, iodine allergy, shellfish allergy, and fluoroscopy.  The included articles were concerned with the basic or clinical science of contrast allergy, including the physiology, epidemiology, diagnosis, and management of such reactions.  Meta-analysis, review articles, and case reports addressing contrast media reactions were also included.  Articles which discussed contrast media reactions in a peripheral fashion were excluded.

RESULTS: In reviewing the literature, it is apparent that the mechanisms and pathophysiology of RCM hypersensitivity reactions are still being characterized, which should soon lead to improved screenings, as well as prevention and treatment strategies. Many common themes are described throughout the literature regarding patient risk factors, testing, prevention,diagnosis, and treatment of RCM allergic-type reactions.

LIMITATIONS: The current review did not perform a meta-analysis of the available data, as most of the available articles were trials that were randomly controlled. Therefore, the conclusions of the present article are general, and qualitative in nature.

CONCLUSION: Although the mechanisms of various RCM allergic-type reactions are not entirely understood, the interventional pain physician should have a basic understanding of patient risk factors, prevention, diagnosis, and treatment of these reactions. The current review allowed for prevention and treatment strategies for managing patients with RCM hypersensitivity reactions.