Endocrine Abstracts

Case Report:
A 69 year old man was referred for assessment of hypoglycaemic events. Type 2 diabetes was diagnosed 4 years previously and treatment with metformin 2000mg per day had provided adequate control (HbA1c 7.5%). In the 4 months prior to referral, the patient had lost 8kg in weight and had had more than 10 episodes of sweating, tremor and disorientation. Eventually capillary blood glucose measurements were undertaken which suggested hypoglycaemia which was confirmed during a clinic visit. HbA1c was low at 5.1%, renal function normal and no other drugs were being taken.
Further testing confirmed the presence of anterior pituitary failure with deficiency of ACTH, TSH, Prolactin, GH and LH/FSH. Hormone replacement with cortisol, thyroxine and testosterone provoked improved well being and abolished the spontaneous hypoglycaemia.
A non-functioning, pituitary adenoma was subsequently removed at operation.
The patient remains well on metformin, hormone replacement with a recent HbA1c of 7.1%.
Hypopituitarism may provoke hypoglycaemia in diabetes, but hypoglycaemia is rare in patients treated with metformin alone with normal renal and liver function. The occurence of hypoglycaemia in otherwise healthy patients on metformin should prompt the clinician to evaluate the possibility of pituitary failure.