Endocrine Abstracts

It can be challenging to differentiate between gestational thyrotoxicosis and intrinsic hyperthyroidism; the former being the commonest cause of thyrotoxicosis in pregnancy and usually requiring supportive care only. A 34 year-old lady, gravida 4 and para 2 was admitted at 11weeks of gestational age with an initial diagnosis of hyperemesis gravidarum. She was referred to the endocrinology due to severe symptoms and tachycardia, palpitations, excessive sweats, >5%weight loss with deranged thyroid function tests. She had hyperemesis gravidarum with gestational thyrotoxicosis in previous two pregnancies with resolution of symptoms after first trimester. Examination showed fine tremors, a diffuse, non-tender goitre without bruit and no evidence of eye disease, acropachy or pretibial myexedema. Biochemistry revealed significantly elevated beta-HCG level of 62700 IU, free thyroxine (FT4) 26.9 (12-22 pmol/l), free triiodothyronine (FT3) 8.86 (2.0-7.0 pmol/l) thyroid stimulating hormone (TSH) <0.02 mIU/L (0.4-4.5 mIU/l), and negative thyroid peroxidase (TPO) and thyrotropin receptor antibodies (TRAB). A diagnosis of gestational thyrotoxicosis was made and she was managed conservatively leading to its spontaneous resolution in second trimester.

Discussion: Gestational thyrotoxicosis occurs from the stimulatory action of HCG on the TSH receptor, as they share structural homology resulting in an increased production of T4 and T3 and a low TSH levels. Differentiation of Graves’ disease from GTT can be supported by the presence of clinical evidence of autoimmunity, a typical goiter, and presence of TRAb. Our patient presented with severe symptoms including weight loss posing challanges in diagnosis and management. In the context of hyperemesis, previous gestational thyrotoxicosis, and the absence of TRAB, a diagnosis of severe gestational thyrotoxicosis was made and treated with close monotand treated with close monoting and supportive care.

Conclusion: Severe gestaional thyrotoxicosis can pose a clinical challenge, adopting a careful approach based on clinical and biochemical features enables accuarte diagnosis and appropriate treatment.