[Iodine-induced hyperthyroidism in urology caused by using roentgen contrast media. Risks and prevention]

The presence of functionally autonomous portions of the thyroid is a precondition for the occurrence of iodine-induced hyperthyroidism after the administration of i.v. contrast media, in the form either of latent immunogenic hyperthyroidism (Basedow's disease) or of localized or diffuse autonomy. The normal thyroid can compensate an iodine excess in multiple ways. In the malfunctioning thyroid, however, autoregulation mechanisms may fail, resulting in complicated forms of hyperthyroidism. In Germany autonomy-correlated hyperthyroidism occurs much more often than in other countries in which sufficient alimentary iodine is present. Especially in elderly patients with long-standing nodular goitres, there is an elevated risk of iodine-induced hyperthyroidism arising from thyroidal autonomy. These cases may differ from those seen in younger patients. An existing hyperthyroidism may worsen dramatically after administration of contrast media. To prevent an iodine-induced thyrotoxic crisis, contrast media should only be given to patients with latent of manifest hyperthyroidism when vital indications are present, and then only after thyrostatics have been administered. To evaluate the morphology of the renal collecting system and ureter in these cases a retrograde rather than an intravenous pyelography should be performed. When this is combined with determination of serum creatinine and creatinine clearance, functional and morphological evaluation, respectively, of the upper urinary tract are possible.