Anaphylactic reaction to orthoiodohippurate.

Area of Science:

• Nuclear Medicine
• Radiopharmaceutical Safety
• Diagnostic Imaging

Background:

• Radiopharmaceuticals like iodinated hippuran are used in renography for kidney function assessment.
• Patients with a history of severe reactions to iodinated contrast media require careful evaluation before subsequent procedures.
• Anaphylaxis is a severe, potentially life-threatening allergic reaction.

Observation:

• A 32-year-old woman developed an anaphylactic reaction after administration of 125I- and 131I-o-iodohippurate during a renography procedure.
• The patient had a documented history of anaphylactic shock following a previous intravenous pyelography, which also utilized iodinated contrast agents.
• The renography was indicated due to the patient presenting with hematuria.

Findings:

• The administration of iodinated radiopharmaceuticals (125I- and 131I-o-iodohippurate) can trigger anaphylactic reactions, even in patients with prior contrast media hypersensitivity.
• A history of anaphylaxis to intravenous pyelography is a significant risk factor for adverse reactions to other iodinated agents used in nuclear medicine.
• This case underscores the potential for severe hypersensitivity reactions to radiopharmaceuticals.

Implications:

• Healthcare providers must meticulously review patient histories for prior allergic reactions to contrast media and radiopharmaceuticals.
• Implementing robust screening protocols is crucial to identify patients at high risk for anaphylaxis before administering radiopharmaceuticals.
• Centralized reporting of all adverse events associated with radiopharmaceuticals is essential for pharmacovigilance and improving patient safety in nuclear medicine.