Intravenous pyelogram, or IVP, is a test done to evaluate the kidneys and urinary tract. Iodinated ionic contrast media, also known as ICM or simply contrast media is injected into a vein to better outline the structures, followed by X-rays of the areas. While contrast dye improves the ability to diagnose kidney and urinary tract problems, it can also cause serious allergic reactions and anaphylaxis.
Older literature reports allergic reactions in between 5 to 8 percent of people undergoing tests with ICM, the Food and Drug Administration reports. Newer agents report serious allergic reactions in between 1.2 and 1.5 percent, with life-threatening reactions occurring in 0.1 to 0.5 percent, the FDA adds.
Despite popular belief, allergy to shellfish doesn’t increase the risk of allergic reaction to contrast dye. A history of allergy in general, however, does increase the risk of developing a hypersensitivity reaction to IVP dye. One large study of 112,000 people showed that overall, allergy reactions occurred in people with a history of allergies 10.2 percent of the time, while non-allergic people had allergic reactions 5.6 percent of the time, an article published in May 2003 by medical student Adam Schlifke and Joel Geiderman, M.D. in the “Canadian Journal of Emergency Medicine” reported.
People with allergies to shellfish and seafood had reactions nearly 15 percent of the time, but so did people allergic to milk, eggs and chocolate. A history of hay fever, asthma or penicillin also increased the risk. People who take beta-blockers medications may also be prone to hypersensitivity reactions to IVP dye.
Symptoms of allergy to IVP dye include hives, itching, facial swelling, especially around the eyes, lips and mouth, nausea, vomiting, difficulty breathing, wheezing, airway closure, low blood pressure, shock, coma and death, in rare cases. Around 500 people die each year in the United States from ICM reactions, Schlifke and Geiderman report. Reactions nearly always start within two hours after dye administration.
Treatment of allergic reaction to IVP dye includes airway maintenance with oxygen administration and medications to reduce bronchospasm, epinephrine and antihistamines. Intravenous fluids help maintain blood pressure along with drugs to raise blood pressure such as dopamine, the FDA explains.
People with allergic histories and people taking beta-blockers have an increased risk of serious allergic reaction to IVP dye. Giving a small test dose may trigger a fatal reaction and is not recommended. People with a high-risk history may benefit from corticosteroid administration, which reduces inflammation, before receiving IVP dye. Most importantly, medical practitioners who perform IVPs must have life-saving equipment at hand and must know how to use it quickly in an emergency, Schlifke and Geiderman warn.
- University of California San Francisco: Iodine Allergy and Contrast Administration
- Australian Prescriber: 'Iodine Allergy' Lable Misleading
- Food and Drug Administration:Mechanistic and Clinical Characteristics of Hypersensitivity Reactions
- "Canadian Journal of Emergency Medicine": Medical Mythology; Adam Schlifke, Joel Geiderman, M.D.; May 2003