Endocrine Abstracts

A 21-year-old woman presented in 2015 with palpitations, weight and hair loss, mood swings and diarrhoea. She was diagnosed with thyrotoxicosis (Table). On examination, thyroid was normal and no evidence of opthalmopathy. Treatment with Propranolol and Carbimazole was commenced.  Ultrasound neck revealed moderate diffuse enlargement of the thyroid with uniformly abnormal echotexture, consistent with thyroiditis.  A month later, she developed profound hypothyroidism, therefore Carbimazole was stopped and Levothyroxine started with subsequent normalisation of thyroid function tests. Later on, Levothyroxine was paused.

She has not required treatment and remained asymptomatic until April 2017, when she suffered a relapsed thyrotoxicosis. Technetium (Tc) scan showed normal homogenous uptake. Thyroid receptor antibodies (TRAbs) were undetectable.  She was commenced on Propranolol and within weeks made a full recovery with no additional treatment.

In September, 2019, she had another relapse of severe thyrotoxicosis. Treatment with Propranolol and Prednisolone was started for a diagnosis of recurrent subacute thyroiditis (SAT). She has developed hypothyroidism, which required Levothyroxine treatment and remained stable on 125 mcg OD.

In December 2019, the patient fell pregnant. She was euthyroid throughout pregnancy on 75/100mcg Levothyroxine. Twelve weeks’ post-partum, in November 2020, she again, presented with thyrotoxicosis. Her Tc scan showed low uptake consistent with postpartum thyroiditis. In 2019/ 2020, her TRAbs were undetectable. Her Levothyroxine was paused. By December, 2020, she became hypothyroid and since then is on Levothyroxine 100mcg and remains well and stable.

Results

Treatment:   Given 4 relapses of severe thyrotoxicosis as a presentation of SAT (1 episode occurred while the patient was on Levothyroxine) and patients’ request, she was referred for thyroidectomy. 

Conclusion:  This case represents an unusual form of thyroiditis where the patient fluctuates between severe hyperthyroidism and hypothyroidism; last episode occurred post-partum. SAT is a rare disease with a recurrence frequency of   20–30%. The reason for SAT relapse is unknown, but an association with HLA-B*18:01 and -B*35 was reported. In such high-risk patients, the steroid treatment regimen should be intensified with a slower dose reduction.