Endocrine Abstracts

Introduction: Graves’ disease is an autoimmune disorder which may lead to thyroid overactivity and eye disease. Oestrogen and progesterone are thought to be immunomodulatory and have been postulated to play an important role in the difference in prevalence of autoimmune disorders between men and women. Autoimmune disorders, including autoimmune thyroid disease, are often quiescent during pregnancy with an increased prevalence postpartum. The increase in immune mediated thyroid disease postpartum has been associated with alterations in oestradiol and progesterone levels.

Case: A 27-year-old lady with a 2-month history of fatigue, tremor, sweating, pruritus, and weight loss. She had been taking the oral combined contraceptive pill (Yasmin) for 3 years, which she stopped just prior to the onset of her symptoms. Examination revealed a diffuse, smooth goitre although no evidence of thyroid eye disease. Thyroid function tests revealed a suppressed TSH at 0.01 mIU/l, free T₄ 41.9 pmol/l, and free T₃ >46.1 pmol/l. TSH receptor antibodies were elevated at 2.2 U/l confirming a diagnosis of Graves’ disease. She was treated with anti-thyroid medication and B-blockade with full resolution of her symptoms.

Conclusion: There are no previously reported cases of autoimmune thyroid disease occurring following cessation of the combined oral contraceptive pill. Graves’ disease often affects young women, who are most likely to be treated with oral contraceptive agents. In a cross sectional study looking at risk factors for autoimmune thyroid disease, Strieder et al. have reported that oestrogen use was associated with a lower rate of hyperthyroidism (RR 0·169) and furthermore oestrogen use was negatively correlated with the presence of TPO antibodies. Thus it seems feasible that the withdrawal of oral contraceptive use may have precipitated the onset of autoimmune thyroid disease in this young woman.