SFEBES2009 Poster Presentations Thyroid (45 abstracts)
Pinderfields General Hospital, Wakefield, West Yorkshire, UK.
An 83-year-old gentleman was referred to the endocrine clinic with incidentally found abnormal thyroid function tests (TFT): TSH <0.02 (0.24.0 mU/l), free T4 20.4 (919 pmol/l), and free T3 7.6 (2.55.7 pmol/l). His TFT done 6 months previously were normal with TSH 1.21 mU/l and FT4 11.8 pmol/l. His past medical history included BPH, peripheral vascular disease and chronic kidney disease (CKD), and medications were tamsulosin, finasteride, aspirin, and lansoprazole. He denied having symptoms of hyperthyroidism, or family history of thyroid dysfunction. He was clinically euthyroid with no goitre or dysthyroid eye disease, but had bilateral gynaecomastia, normal body hair and testicular volumes. Direct enquiry revealed on-going breast enlargement for 23 months; there was no recent change in his drug history. Subsequent tests confirmed hyperthyroidism with TSH <0.02 mU/l, FT4 20.4 pmol/l and FT3 6.9 pmol/l. Other tests included negative thyroid-peroxidase antibodies, normal liver function tests, stable CKD stage 3, normal HCG, LH 13.4 (210 IU/l), FSH 12.6 (212 IU/l), testosterone 10.2 (830 nmol/l), ostradiol 98 (0150 pmol/l) and SHBG 116 (1471 nmol/l). A diagnosis of gynaecomastia due to hyperthyroidism was made and carbimazole-therapy initiated. He rapidly developed tiredness, albeit with normal FBC and unchanged TFT, and was changed to propylthiouracil 150 mg/day. After 10 weeks, his biochemical abnormalities and gynaecomastia improved. Thyroid ultrasound revealed an 8×6 mm nodule. Radioactive-iodine is planned as the definitive treatment for hyperthyroidism.
Gynaecomastia as the sole manifestation of hyperthyroidism is very rare, although is a well-documented clinical feature, reported in 244% of male patients with thyrotoxicosis. Altered oestrogen-to-androgen ratio, increased SHBG, enhanced peripheral aromatase activity, all contribute to hyperthyroidism-related- gynaecomastia, but exact mechanism is unknown. Gynaecomastia is common in men over 70 years (up to 55% at autopsy); could be due to aging-related endocrine/metabolic changes, drugs, medical conditions, etc. Aging, finasteride, lansoprazole, CKD, hyperthyroidism multiple causes of gynaecomastia in our patient but improvement was noted on achieving euthyroidism. It is important to recognise hyperthyroidism as a reversible cause of gynaecomastia in the increasing elderly population.