Time course to hypothyroidism after fixed-dose radioablation therapy of Graves' disease in children.
OBJECTIVE
To characterize the development of hypothyroidism in pediatric patients who receive a fixed dose of radioactive iodine (RAI).


METHODS
Medical records of children treated with fixed-dose RAI for Graves'disease between 1993 and 2001 were reviewed. Multiple variables including sex, age, thyroid hormone levels, thyroid-stimulating immunoglobulin titer, antithyroid medication use, and 24-hour radioiodine uptake were investigated as possible predictive factors for the development of hypothyroidism after treatment. All patients received RAI at a dose of between 13.8 and 15.6 mCi (average, 14.7 mCi; SD, 0.5).


RESULTS
Permanent hypothyroidism developed in all 40 patients, although a second dose of RAI was required in one case. The average time to hypothyroidism was 77 days (SD, 32), with a range of 28 to 194 days; 75% of the patients were diagnosed with hypothyroidism between 40 and 90 days. RAI treatment was ineffective in an additional patient, who required subtotal thyroidectomy.


CONCLUSIONS
We conclude that a fixed dose of RAI is effective therapy in nearly all pediatric patients with Graves'disease. Factors predicting the time course to hypothyroidism were not identified.
Nebesio
Todd D
TD
Section of Pediatric Endocrinology/Diabetology, Department of Pediatrics, James Whitcomb Riley Hospital for Children, Indianapolis, Indiana 46202, USA.
Siddiqui
Aslam R
AR
Pescovitz
Ora H
OH
Eugster
Erica A
EA
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006111:Graves Disease / Q000532:radiotherapy*; D006801:Humans; D007037:Hypothyroidism / Q000453:epidemiology* / Q000209:etiology; D007196:Indiana / Q000453:epidemiology; D007457:Iodine Radioisotopes / Q000008:administration & dosage*; D008297:Male; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D013997:Time Factors
D007457:Iodine Radioisotopes