A 57-year-old woman presented with a 4-week history of lethargy, weight loss, polyuria, and polydipsia. Her only past medical history of note was hypertension for which she was taking lisinopril. On admission her initial investigations showed: glucose 22.6 mmol/l, capillary blood ketones Hi and a metabolic acidosis (H+57.5 nmol/l and HCO3− 13.7 mmol/l). She was commenced on the DKA protocol and her acidosis resolved without complication. She was maintained on a variable rate insulin infusion until she was eating and drinking. Her daily intravenous insulin requirement was in excess of 150 units/day. Her HbA1c was 110 mmol/mol and anti-GAD antibodies were strongly positive (>2000 units/ml). She was reviewed by the inpatient diabetes team, started regular s.c. insulin and was noted to have clinical features of acromegaly, course facial features, doughy hands and prognathism. Anterior pituitary function showed a baseline cortisol <40 nmol/l rising to 404 nmol/l after ACTH stimulation, protactin 47 nU/l, fT4 10 pmol/l, TSH 0.24 mU/ l, and inappropriately low gonadotrophins and oestradiol. Oral glucose tolerance test showed no suppression of GH (2-h value of 2.6 ng/ml). IGF1 was elevated at 603 μg/l. An MRI pituitary confirmed a macroadenoma (17×18×20 mm) abutting the optic chiasm and extending into the right cavernous sinus. Formal visual field assessment was normal. She started replacement hydrocortisone, somatostatin analogues and she is awaiting neurosurgical review.
Acromegaly is often associated with T2DM. Although our patient has T1DM, the suspicion of concurrent insulin resistance arose from a high fasting intravenous insulin requirement. Biochemical interpretation of GH and IGF1 levels can be difficult in poorly controlled diabetes. However, our patient had clinical features consistent with acromegaly and a pituitary mass making the diagnosis unequivocal. This case highlights the need for speciality assessment in all patients presenting with DKA.