Serum C-reactive protein concentrations increase after radioiodine therapy in patients with hyperthyroidism
(July 2007)
The background of the study. Radioactive iodine (I-131) therapy for hyperthyroidism results in acute thyroid inflammation, with increases in serum antithyroid antibody concentrations. In this study, serum free thyroxine (T4), thyrotropin (TSH), thyroglobulin, antithyroid antibodies, and markers of inflammation were measured before and after I-131 therapy in patients with hyperthyroidism.
How the study was done. The study subjects were 26 patients with hyperthyroidism (average age, 48 years); 19 had hyperthyroidism caused by Graves’ disease and seven a toxic nodular goiter. They were treated with 8 to 15 mCi (296 to 555 MBq) of I-131.
White-cell counts, red-cell sedimentation rate (ESR), C-reactive protein, free T4, thyroglobulin (a product of the thyroid), and antimicrosomal antibodies (also known as antithyroid peroxidase antibodies) were measured before and repeatedly for three months after I-131 therapy.
The results of the study. Serum free T4 concentrations decreased and TSH concentrations increased after I-131 therapy in all patients. The average serum thyroglobulin concentration increased four weeks after therapy and then decreased. The white-cell counts and ESR values did not change, but serum C-reactive protein concentrations increased slightly from 3.7 mg/L at base line to a peak value of 5.7 mg/L 1 week after I-131 therapy. Serum antimicrosomal antibody concentrations increased from 159 U/ml to 636 U/ml three months after therapy.
The conclusions of the study. Serum C-reactive protein and thyroglobulin concentrations increase transiently after I-131 therapy in patients with hyperthyroidism, indicative of I-131-induced thyroid inflammation.
The original article. Sari O, Tunc R, Kisakol G, Dostbil Z, Serdengecti M. Acute-phase response after radioiodine treatment on hyperthyroidism. Endocrinologist 2007;17:89-91.
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