Anaphylactic Shock Following Administration of Iodinated Computed Tomography (CT) Contrast Media: A Case Series

Anaphylactic shock is a severe and life-threatening allergic reaction that can result from contrast agents used in imaging procedures. Iodinated contrast media (ICM) are indispensable in diagnostic computed tomography (CT), yet they carry a small but serious risk of anaphylactic reactions. Even with low-osmolar, nonionic agents such as iohexol, severe hypersensitivity can occur unpredictably, including in patients with no prior history of allergic reactions. We report a retrospective case series of three patients who experienced anaphylactic shock following administration of ICM during CT imaging at Hamad Medical Corporation, Doha, Qatar. Cases were identified through clinical incident reporting and radiology department records. Anaphylaxis was diagnosed according to clinical criteria, requiring an acute onset of symptoms involving compromise of two or more organ systems such as cardiovascular, respiratory, or cutaneous, following intravenous (IV) contrast media exposure. Patient data were extracted from electronic medical records, including clinical notes, nursing observations, laboratory investigations, and imaging reports. Informed consent was obtained from patients, and the report was compiled in accordance with institutional ethical guidelines. Cases 1 and 3 involved female patients with breast cancer receiving iohexol for oncological staging. Case 2 included a male patient with multiple comorbidities who received iodixanol for cardiac evaluation. In all three cases, anaphylaxis developed shortly after IV contrast administration and was successfully managed with epinephrine, corticosteroids, antihistamines, and IV fluid administration. All patients achieved full recovery without long-term complications. These cases underscore the unpredictable nature of contrast-induced anaphylaxis and the critical importance of preprocedural risk assessment, emergency preparedness, and rapid administration of treatment. Even patients without identifiable risk factors may develop life-threatening reactions, emphasizing that all contrast-administering settings must maintain robust emergency protocols.