Endocrine Abstracts

A 62-year-old male was referred by his GP querying acromegaly. His past medical history included sleep apnoea, hypertension, dislipidaemia and gout. Serum IGF1 was elevated at 827 ug/l (normal range 100–300 ug/l). Prolonged oral glucose tolerance did not show suppression of GH with a nadir of 9.0 mu/l. A pituitary MRI demonstrated a 5x6mm microadenoma. There were no visual field defects. The patient was pre-treated with somatostatin analogues and proceeded to transphenoidal hypophysectomy which was performed without complications.

Post-operatively he developed fatigue and sweats and hypogonadotrophic hypogonadism was confirmed biochemically (LH 2.2 iu/l, FSH 4.0 iu/l, Testosterone 7.9 nmol/l). The patient was prescribed Testogel 5 g/50 mg once a day. The remainder of his pituitary function was assessed and was within normal limits.

The patient’s replacement was sub-optimal on 5 g/50 mg daily (LH 1.5 iu/l, FSH 3.6 iu/l, testosterone 3.6 nmol/) and so the dose was increases to 10 g/100 mg daily. This improved symptoms and normalised serum testosterone (LH 0.4 iu/l, FSH 1.4 iu/l, testosterone 18.8 nmol/).

The addition of newer methods in prescribing testosterone has been associated with an increase in the frequency of prescribed topical testosterone replacement regimes. In acromegaly, increased skin thickness is almost pathognomonic of the condition and may cause reduced absorption of topical testosterone.

Our patient’s skin thickness was increased on plain heel X-ray (at 34 mm in thickness, normal range <33 mm). This abstract demonstrates that modern treatment of hypogonadism with topical agents in patients with acromegaly may need revising with regard to the potential for larger doses being required for decreased absorption through thickened dermal layers.