Early identification of primary hypothyroidism in neonates exposed to intralymphatic iodinated contrast: A case series

Abstract

Context: In neonates, iatrogenic hypothyroidism can result from topical or IV iodine exposure. Data on intralymphatic iodine exposure, risk factors for disease severity, and timing of hypothyroidism are limited. Case Descriptions: We report 4 cases of premature neonates with previously normal thyroid function tests (TFTs) who developed hypothyroidism after intralymphatic iodinated contrast. Patients 1 and 2, premature infants with complex medical histories, had chylous effusions and highvolume chest tube output requiring imaging with lymphangiograms on day of life (DOL) 97 and DOL 43, respectively. They developed severe, primary hypothyroidism with TSH of 335.7 mIU/mL (reference range, 1.7 to 9.1) on DOL 111 and TSH of 470.2 mIU/mL (reference range, 1.7 to 9.1) on DOL 68. Patient 3 had prenatally diagnosed fetal hydrops manifesting with chylous effusions and high-volume chest tube output. The infant underwent lymphangiography on DOL 90 and was noted to have an elevated TSH of 13.35 mIU/mL (reference range, 1.7 to 9.1) 4 days later with spot urine iodine of 1742 μg/L (normal,