Glyn et al. describe the case of a 57-year-old woman who became unwell after a total thyroidectomy for management of Graves’ disease. She subsequently underwent numerous investigations and treatments over 20 years for a constellation of symptoms including myopathy, arthropathy, pericardial effusion, bilateral ptosis with impaired renal function, thyrotrophin (TSH) 2mIU/l, creatine kinase >1000IU/l and cholesterol 12.5mmol/l.

An astute clinical biochemist reviewed this patient’s history and blood results, added on free thyroid hormones and identified profound central hypothyroidism: free thyroxine (fT4) <0.4pmol/l (normal range (NR) 12–22pmol/l), free triiodothyronine <0.3pmol/l (NR 3.1–6.8pmol/l) and TSH 2mIU/l. Thyroxine was started (25μg/day) and slowly titrated over a year. Her symptoms improved and other biochemical indices normalised.

This case highlights the importance of reviewing fT4 as well as TSH, but raises the issue of whether this is possible for all thyroid function tests requested nationwide. It demonstrates the importance of introducing thyroid hormones slowly with thyroxine and not reaching for the intravenous liothyronine. It also demonstrates the importance of reviewing all available information and having a curious mind. If the clinical biochemist concerned had not thought about what was happening, this patient may never have had a diagnosis, and the outcome would have been far less successful.

Read the full article in Endocrinology, Diabetes & Metabolism Case Reports 12 EDM-17-0112