Endocrine Abstracts

Introduction: Iodine deficiency in Western countries is considered a historic disease. In 1924 up to 30% of school aged children in the UK had a goitre. The UK however remains one of the most iodine deplete countries in the world. Those following restricted diets are also at particular risk of iodine deficiency.

Case Report: A nine year old female on a significantly restricted diet due to multiple food allergies presented with a goitre. Ultrasound scan confirmed a diffusely enlarged heterogenous thyroid gland. The patient was clinically and biochemically euthyroid, TSH 2.16 mIU/l (0.5–3.6), FT4 14.2 pmol/l (10–16.9). Urinary iodine levels confirmed a goitre secondary to iodine deficiency (urinary iodine 0.09 micromol/l) (0.39–1.97)). Treatment of the iodine deficiency proved challenging, with difficulties finding an appropriate preparation and ensuring compliance with the regime. Preparatory sea kelp, containing 150 micrograms iodine was used. Support from dieticians and the allergy team was also required. One year later, she presented with tremor, heat intolerance and poor concentration. Clinical assessment was in keeping with a hyperthyroid state, confirmed on biochemical testing: TSH <0.01 mIU/l (0.5–3.6), FT4 42.8 pmol/l (10–16.9), T3 >30.7 pmol/l (4.4–6.8). TSH receptor antibodies, thyroid peroxidase antibodies and anti-thyroglobulin antibodies were negative. The Jod-Basedow Effect was diagnosed secondary to repletion of iodine stores. She was initially managed with carbimazole and propranolol. As her thyroid function normalises, her medications are now being weaned and stopped.

Conclusions: This case highlights the importance of a dietary history and consideration of iodine deficiency in any patient presenting with a goitre. The Jod-Basedow Effect may be seen as a rare complication of treatment with iodine, and should be considered if iodine-deficient patients on treatment present with thyrotoxicosis. Prognosis is excellent with complete resolution in antibody-negative patients