Thyroid, renal, and hepatic function tests following cholecystography with high-dose contrast agents

Area of Science:

• Endocrinology
• Radiology
• Clinical Chemistry

Background:

• Oral cholecystography utilizes iodinated contrast agents for gallbladder imaging.
• Iopanoic acid (Telepaque) and sodium ipodate (Biloptin) are commonly used agents.
• Potential systemic effects of these agents on biochemical parameters require investigation.

Purpose of the Study:

• To evaluate the impact of high-dose oral cholecystography agents on serum biochemical markers.
• To assess changes in thyroid hormone levels and other biochemical parameters following administration of iopanoic acid or sodium ipodate.
• To determine the duration of these biochemical alterations.

Main Methods:

• Serum biochemical tests were monitored in patients undergoing oral cholecystography.
• Two contrast agents, iopanoic acid and sodium ipodate, were administered at high doses (6 g).
• Blood samples were analyzed over a three-week period post-administration.

Main Results:

• No significant changes in renal or hepatic function were observed, apart from a mild bilirubin increase.
• Thyroid-stimulating hormone, thyroxine, and free thyroxine index increased significantly, while triiodothyronine decreased.
• Reverse triiodothyronine showed a sharp increase, suggesting interference with iodothyronine deiodination.

Conclusions:

• Oral cholecystography agents can transiently affect thyroid function tests, potentially leading to supranormal thyroxine levels.
• These changes are likely due to interference with extrathyroidal deiodination of iodothyronines.
• Thyroid function tests require careful interpretation in patients within three weeks of receiving iopanoic acid or sodium ipodate.