Endocrine Abstracts

Introduction: The common causes of thyrotoxicosis are Graves’ disease, toxic multinodular goitre and toxic adenoma which account for >90% of cases of this condition. Iodine-induced thyrotoxicosis (Jod-Basedow syndrome) is infrequently considered as a cause of thyrotoxicosis. This case describes a lesser known cause of iodinated contrast-induced thyrotoxicosis.

Case Report: A 47 year old man with known alcoholic liver disease and recurrent pancreatitis had two hospital admissions within a space of a few weeks under 2 different teams-surgery and medicine with four contrast CT scans performed during this time. He was diagnosed and treated for alcoholic hepatitis. He developed new onset tremor after few weeks of his admission. His thyroid function test (TFT) showed thyrotoxicosis with TSH<0.01 mU/l, T4 33.7 nmol/l, T3 4.5 nmol/l. There was 12 day delay in his parent team referring him to Endocrinology due to various factors. His only symptom was of tremor. He had been abstinent from alcohol for >4weeks since his admission. He did not have any previous or family history of thyroid disease. He was on amiodarone which was stopped 3 months prior due to prolonged QTc. He did not have a palpable goitre and had mild tremor of the outstretched hands on examination. Upon repeat, his thyroid function test showed improvement with suppressed TSH, T4 25.6 nmol/l and T3 4.2 nmol/l. He was diagnosed to have iodinated contrast induced thyrotoxicosis and a monitoring approach was instituted. His TFTs normalised within 10 weeks and remained so for 3 months later. His TRAb was mildly positive.

Conclusion: Iodine-based contrast agents are widely used in angiographic and other radiological procedures providing patients with supraphysiological load of organic iodide. There needs to be increased awareness of the risk of thyrotoxicosis in susceptible patients undergoing radiological investigations by non-endocrinologists and awareness by endocrinologists of this cause of thyrotoxicosis.