Endocrine Abstracts

Introduction: Hashitoxicosis is the rare case of autoimmune thyroid disease. While transforming from Graves’ disease to spontaneous hypothyroid is well known, development of hyperthyroidism following hypothyroidism is a rare phenomenon which can pose a challenge in management. We report here a case of Hashitoxicosis managed with "Block and Replace Therapy" to maintain her euthyroid while waiting for definitive therapy.

Case Report: A 30-year-old lady with background history of hypothyroidism and migraines was referred to endocrine service with persistent symptomatic hypothyroidism; lethargy, menorrhagia and dry eyes despite treated with Levothyroxine. Her weight was 66.4 kg. Clinically, there was a large soft goiter, large right palpebral fissure without suggestive features of minor thyroid eye disease. Biochemically consistence with hypothyroidism; TSH 10.21 mU/l (0.35-5.50) and T4 10.9 pmo/l (10.0-20.0). Her family history included autoimmune hyperthyroidism, hypothyroidism, vitiligo and vitamin B12 deficiency. She became clinically thyrotoxicosis after 3 months with fine tremors and palpitation with heart rate of 200 bpm and biochemically with TSH 0.01, T4 47.6 and T3 10.5. The levothyroxine dose was reduced. Thereafter, her TSH went up to 26.12, T4 9.4 and TPO Antibodies >1300. Her thyroid function test was closely monitored due to labile state. The patient declined the definitive management (Radioactive iodine and thyroidectomy) initially as she was looking after two young children and cosmetics reasons. Therefore, ’ Block and Replace therapy’ was commenced in consideration of labile thyroid status and stopped once the euthyroid state was maintained (TSH 1.43, T4 12.4) over 16 months. Afterwards, the TSH went up to 29.7 and T4 12.4. She was started on Levothyroxine and referred to surgeons for thyroidectomy after discussion in endocrine MDT.

Conclusion: It was a challenging management of fluctuating thyroid status which also highlighted that the clinicians should be aware of potential transformation from blocking to stimulating antibodies.