Endocrine Abstracts

Introduction: First treatment in Graves’ disease consists in the administration of antithyroid drugs. The most common side effect is a rash, which affects about 5% patients and clears up if the drug is stopped. The other drug may then be used. The intolerance to both drugs is very rare, but in this situation early radioactive iodine or surgery may be the answer.

Case report: Woman of 61 years old who developed primary hyperthiroidism, with levels of thyrotropin (TSH) 0.01 μUI/ml (laboratory reference values 0.4–4.2) and free T4 (fT4) 2.19 ng/dl (laboratory reference values 0.93–1.7). Thiamazol 15 mg daily was iniciated. After twenty days, she developed an itchy rash with erythema, which dissapeared when the drug was discontinued. Then we iniciated propylthiouracil 150 mg daily. Three weeks later, she referred similar symptons, and we stopped medication. Consequently, fT4 elevated again. We decided the best treatment was total thyroidectomy, because Radioiodine therapy has a late onset of action and this procedure in our hospital is delayed for several months. In this context, she underwent renal arteriography with iodinated contrast material. To avoid thyrotoxicosis, we iniciated Lugol’s iodine solution Forte 5%, 8 drops every 6 hours, five days before the study. A stent was placed in renal artery, and clopidogrel was indicated for two months. So anesthesiologist recommended delaying surgery until clopidogrel was discontinued and thyroid function was normalized. The only therapeutic option we found was to maintain Lugol until surgery, and monitorize hormone levels every two-three weeks. We reduced empirically Lugol dosage to 5 drops every 6 hours, and fifteen days later the thyroid function was normalized (TSH 0.5 μUI/ml, fT4 1.53 ng/dl). Five weeks after the start of Lugol, she developed mild hypothyroidism (TSH 11.39 μUI/ml, fT4 0.89 ng/dl). Again empirically, we maintained same dose of Lugol and added low-dose of levothyroxine. Eight weeks after start of Lugol, TSH was 5.43 μUI/ml and fT4 1.33 ng/dl. She undergone total thyroidectomy ten weeks after starting Lugol. The only complication was transitory hypoparathyroidism. Actually her thyroid function is adequately replaced with 100 μg of sodium levothyroxine.

Conclussion: Iodine solutions were used in the 1930s as the sole therapy for mild hyperthyroidism before the introduction of tionamides. Today, they still play a minor role in the treatment. We recovered this therapy and demonstrated that this ‘obsolete’ drug could have a rol in selected cases.