Lugol's Iodine as a Key Treatment in Transient Gestational Thyrotoxicosis: A Case Report

Transient gestational thyrotoxicosis (TGT) occurs when human chorionic gonadotropin (hCG) directly stimulates the maternal thyroid gland during the first trimester of pregnancy. We report a case of complicated TGT in a young woman who required treatment with Lugol's solution.

A 29-year-old pregnant woman, at 10 weeks gestation and with no significant medical history, was referred to the endocrinology department for evaluation of hyperthyroidism. She had been experiencing persistent vomiting, anorexia, fatigue, palpitations, abdominal pain, and unintentional weight loss for 2 weeks. On examination, her heart rate was at 120 bpm, and she exhibited resting tremors, but there were no signs of exophthalmos or goiter. Laboratory results revealed a free T4 level 2.2 times above the upper limit of the normal range, with a thyroid-stimulating hormone (TSH) level of 0.01 mUI/L. Tests for thyroid receptor antibodies, thyroid peroxidase antibodies, and anti-thyroglobulin antibodies were negative. A cervical ultrasound with Doppler showed a normal-sized thyroid gland without hypervascularity or nodules, confirming the diagnosis of TGT.Additionally, liver enzyme abnormalities were observed, with ASAT elevated 4.84 times and ALAT 3.42 times the normal limit. Also, acute pancreatitis was diagnosed, as evidenced by a lipase level three times above the upper limit of normal. Given the contraindications for antithyroid drugs (ATDs) and glucocorticoids, treatment was initiated with Lugol's iodine 5% (five drops three times daily) and propranolol (60 mg/day) for 2 weeks. Symptoms of thyrotoxicosis resolved, free T4 returned to normal levels, and liver enzymes normalized.

This case highlights the interesting role of Lugol's iodine as a short-term and effective therapeutic option in selected cases of TGT.