Endocrine Abstracts

Introduction: The contrast agents iopanoic acid and ipodate are potent inhibitors of thyroid function, reducing type I deodinase T₃ generation, inhibiting thyroid liberation of T₄ and T₃, and T₃ receptor binding, with off-label use in hyperthyroid emergencies. However, since the interruption of iopanoic acid production this year, neither agent is currently available in Spain.

Case report: A 34-year-old male was admitted to our hospital’s ICU in acute pulmonary edema. He had noted weight loss, palpitations, nervousness, fatigue and hyperhidrosis during the previous months. Dyspnea at rest. Physical examination: Temperature(T) was 39°C, heart rate (HR) 133/min, irregular; bilateral exophthalmos; pronounced eyelid retraction, positive Graefe and Moebius signs; firm grade III goiter; intense thyroid bruit; precordial thrill; systolic IV/VI mitral murmur; bilateral wet rales; peripheral edema reaching knees; intense fine tremor of tongue and hands. TSH: 0.00 (0.34–5.6 mUI/l), fT₃: 19.99 (2.5–3.99 pg/ml), fT₄ 54.56 (5.8–16.4 pg/ml). EKG: atrial fibrillation. Chest X-ray: cardiomegaly, pulmonary edema. Echocardiography: biventricular dilation; moderate mitral and tricuspid regurgitation; moderate pulmonary hypertension. Patient received 80 mg metimazol, i.v. hydrocortisone, furosemide, 1 mg i.v. propanolol without improvement. Endocrinology was consulted and advised use of the last pills of iopanoic acid: 1 g q12 h, 2 mg i.v. Dexamethasone q6 h. Eight hours later: HR was 97; T 37.3°; fT₃ 8.95. At 14 h: HR 93; T 36; fT₃ 6.34, no dyspnea. 24 h: HR 89, reduced bruit and thrill. Total thyroidectomy was performed on day 10. Six weeks later the patient was asymptomatic, in sinus rhythm, on levothyroxine and propanolol alone.

We conclude that iopanoic acid should be reintroduced into the thyroid pharmaceutical arsenal.