Endocrine Abstracts

Silent and post-partum thyroiditis are autoimmune conditions, which result in a triphasic thyroid hormone disturbance. They are distinguished by the later condition’s relation to pregnancy. Their association in the same patient resulting in recurrent episodes of silent thyroiditis suggests a common aetiology.

We report a 32-year-old female with post-partum and recurrent silent thyroiditis continuing over a decade. She presented post-partum with thyroid overactivity, followed by hypo- and euthyroidism. Over the next 10 years, she had seven episodes of hyperthyroidism; thyroid function tests in the interim periods showed euthyroidism or compensated hypothyroidism. During one toxic episode, a raised thyroglobulin level (189.1 μg/l) was found and a thyroid pertechnetate scan showed no uptake. She never exhibited clinical evidence of Grave’s disease (no goitre, infiltrative orbitopathy or dermopathy) nor of subacute thyroiditis (no viral prodrome and no neck tenderness). The occurrence of recurrent hyperthyroid episodes alongside raised thyroglobulin levels, the absence of neck tenderness and scintigraphic findings indicate she had a combination of post-partum and recurring episodes of silent thyroiditis.

Painless silent and post-partum thyroiditis are normally self-limiting and non-recurring conditions. They show a triphasic thyroid hormone response of thyroid overactivity, followed by hypothyroidism and recovery to a euthyroid state. A minority of patients remain permanently hypothyroid. Our patient showed this classic hormone profile alongside raised thyroglobulin levels (excluding thyrotoxicosis factitia) and low uptake on thyroid scintiography (excluding Graves disease). Silent thyroiditis is uncommon but may be underdiagnosed and there is limited information on recurrence rates, variably described in between 5 and 65% of patients. The association of both recurrent silent and post-partum thyroiditis in our patient suggests these are likely to be a single disorder with a common aetiology. Radioiodine ablation of the thyroid is planned to prevent relapse.