Endocrine Abstracts

We present the case of a 50-year-old lady who initially presented to the endocrine department at Royal Bolton Hospital in 2011 with symptoms of tiredness and lethargy following hysterectomy and bilateral salpingo-oophorectomy in 2003. Hormone replacement therapy was not commenced in view of a strong family history of breast cancer. There is a family history of both autoimmune hypothyroidism and hyperthyroidism. Thyroid function tests were normal, with a positive thyroid peroxidase antibody. She felt her symptoms were due to her thyroid status and was requesting thyroid armour. Following lengthy discussions, no replacement was commenced, but she was referred on for a second opinion.

She represented in 2014 with symptoms of thyrotoxicosis. On further questioning, it revealed that she was commenced on levothyroxine following a single blood test that suggests hypothyroidism. However, she did not tolerate this and resorted to buying thyroid armour herself. She became clinically and biochemically thyrotoxic and was advised to stop thyroid armour.

Her symptoms persisted following discontinuation of thyroid armour. Biochemistry done showed; TSH <0.003 mU/l (0.1–4.0), free T₄ 25.9 pmol/l (8–20), total T₃ 5.6 nmol/l (1.1–2.8), TSH receptor, and TPO antibodies were positive. Thyroid ultrasound showed diffuse thyroid inflammation and increased vascularity. This is in keeping with autoimmune thyroid disease. She was commenced on carbimazole.

As there was no record of previous TSH receptor antibody, we don’t know if she has both stimulating and blocking TSH receptor antibody to account for her symptoms. What we speculate is the possibility of porcine antibodies from thyroid armour which contributed to her autoimmune thyrotoxicosis. There are many articles in relation to thyroid armour in treating hypothyroidism and subclinical hypothyroidism, but none to suggest a causative factor in developing autoimmune hyperthyroidism. The American Thyroid Association encourages future research in long-term outcome trials looking into thyroid extracts.