Iodinated contrast prior to evaluation for thyrotoxicosis

Radioactive iodine is useful in the diagnosis and treatment of patients with newly diagnosed thyrotoxicosis. However, in many patients these tests are not possible to obtain due to recent administration of iodinated contrast for other types of diagnostic studies, most frequently computed tomography (CT) scans.

To determine the frequency of iodinated contrast use in hospital inpatients newly diagnosed with thyrotoxicosis and the utility of these studies.

Retrospective chart review.

Academic medical center.

None.

Inpatients with newly diagnosed thyrotoxicosis who were seen in consultation by the endocrinology service.

The records of inpatient endocrinology consultations (n = 1171) performed by our service over a 4-year period were reviewed. Records of patients with newly diagnosed thyrotoxicosis were identified and reviewed to determine if iodinated contrast had been recently administered, the types of studies it was used for, and the results of those studies.

Forty-five patients (45%) had been given iodinated contrast within 2 weeks prior to endocrinology evaluation, 43 for CT scanning, and 2 for angiography. Of the patients who underwent CT scanning, 7 (16%) had a finding that potentially changed their inpatient management. Only 1 of these patients required emergent treatment of a condition diagnosed by CT scan before further diagnostic studies could have been performed.

A substantial number of inpatients with thyrotoxicosis receive iodinated contrast prior to endocrinologic evaluation. Acute findings from these studies that change patient management are uncommon. Awareness of this issue may facilitate care of hospitalized patients with thyrotoxicosis.