Comprehensive Nursing Pharmacology Q 268


The nurse is aware that the patients who are allergic to intravenous contrast media are usually also allergic to which of the following products?
  
     A. Eggs.
     B. Shellfish.
     C. Soy.
     D. Acidic fruits.
    
    

Correct Answer: B. Shellfish
Some types of contrast media contain iodine as an ingredient. Shellfish also contain significant amounts of iodine. Therefore, a patient who is allergic to iodine will exhibit an allergic response to both iodine-containing contrast media and shellfish. Fish and shellfish contain iodine, and allergic reactions to seafood are quite common, with a prevalence ranging anywhere between 2% and 6% of the population. As a result, patients with suspected shellfish allergies are often told by providers that they are allergic to iodine. In 1 study, nearly 92% of patients presenting to a pediatrics clinic with a suspected seafood or shellfish allergy cited iodine as the culprit.
Option A: As contrast?enhanced CT scans utilize a variety of iodine?based agents, patients are often told to avoid CT scans with iodinated contrast agents or receive corticosteroid/antihistamine premedications prior to undergoing CT scans to mitigate potentially life?threatening allergic reactions.
Option C: A survey of radiologists and interventional cardiologists revealed that 65.3% and 88.9%, respectively, asked about seafood or shellfish allergies prior to administering contrast-enhanced CT scans, and 34.7% and 50.0%, respectively, stated that they would withhold contrast media or recommend premedication with corticosteroid/antihistamines for patients with seafood or shellfish allergy.
Option D: Although fish and shellfish contain iodine, so to do a wide variety of commonly consumed foods (eg, yogurt, milk, bread). In addition, our bodies contain and require sufficient quantities of iodine for basic functions, making immune reactions to such an essential ingredient of life unlikely. Instead, fish and shellfish contain proteins (parvalbumin and tropomyosins, respectively), which act as the major allergens, not iodine.