Introduction: Central hypothyroidism is frequently seen after pituitary surgery, radiation therapy or head injury. We present a case of silent thyroiditis in a patient with secondary hypothyroidism. Case Description A 24 year old woman complained of tiredness during her periodic review in the endocrine clinic. Her endocrine history included surgery for craniopharyngioma at the age of 3 years and subsequent hypopituitarism with growth hormone, ACTH deficiency, diabetes insipidus, and hypogonadotropic hypogonadism. At the age of 20 she developed partial secondary hypothyroidism; TSH=6 mU/L (0.54.7) and FT4=7.6 pmol/L (924). Her hormonal replacement included hydrocortisone 25 mg/day, Desmospray 900 mcg/day, growth hormone 0.6 mg/day and Levothyroxine 150 mcg/day. She had no family history of thyroid disease. On examination the patient did not have a goitre, neck tenderness or features of Graves disease. Her thyroid function tests (TFTs) confirmed hyperthyroidism; TSH <0.05 mU/L, FT4=55 pmol/L and FT3=18 pmol/L (2.53.3). Her Levothyroxine was discontinued and her TFTs two months later showed TSH <0.05 mU/L, FT4=28 pmol/L and FT3 5.8 pmol/L. TPO Ab was 769 u/ml (075). She was not started on anti thyroid medication and over one year of follow up her TFTs returned to baseline TSH 0.85 mU/L, FT4 9.7 pmol/L and FT3 3.5 pmol/L. Her Levothyroxine was restarted.
Discussion: Patients with central hypothyroidism can still present with thyroiditis or primary hyperthyroidism. Silent thyroiditis is an uncommon condition and its occurrence in combination with secondary hypothyroidism is rare. We could only find one similar case report. Ideally, a thyroid uptake scan would have been very helpful but unfortunately the patient did not attend a few of the next clinic appointments.
Conclusions: Thyroiditis and primary hyperthyroidism could occur in patients with central hypothyroidism and it is important to consider the diagnosis in these patients.
Declaration of interest: There is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported.
Funding: No specific grant from any funding agency in the public, commercial or not-for-profit sector.