DIABETIC KETOACIDOSIS AS FIRST PRESENTATION OF A GROWTH HORMONE AND PROLACTIN CO-SECRETING PITUITARY MACROADENOMA

Abstract

INTRODUCTION
Diabetic ketoacidosis (DKA) is an uncommon initial presentation in acromegaly. Acromegaly is a state of elevated levels of both growth hormone (GH) and insulinlike growth factor-1 (IGF-1), known to cause insulin resistance subsequently leading to hyperglycaemia. The association between hyperprolactinemia and insulin resistance has also been described widely in literature. This is the first case ever reported as growth hormone and prolactin co-secreting pituitary macroadenoma initially presenting as DKA.

CASE
We report the case of a 46-year-old Malay gentleman with obesity and smoking history who presented with fever, vomiting, lethargy and altered behaviour for 3 consecutive days. Biochemically fulfilled criteria of severe DKA was resolved with vigorous intravenous fluid administration and high dose intravenous insulin infusion. He was subsequently shifted to high dose subcutaneous insulin to achieve optimum glucose control. Further exploration revealed that he had experienced mild increased size of hands and feet. Physical examination showed mildly coarsened, enlarged facial features. Initial computed tomography of the brain showed widened sella turcica. Magnetic resonance imaging of the brain confirmed the presence of a pituitary macroadenoma with local mass effect. Blood screening revealed an elevated IGF-1 (681 ng/mL) and an extremely high level of prolactin (>10,000 mIU/L). Growth hormone suppression test taken in an outpatient setting when the patient was euglycemic revealed unsuppressed GH. Ophthalmological examination revealed bilateral visual field defect. She was started on cabergoline treatment and was later referred to the neurosurgical team for further surgical management.

CONCLUSION
This case highlights the importance of considering acromegaly as an alternative cause of DKA at initial presentation, other than the more common causes of type 1 or 2 diabetes. Early identification of the primary cause for DKA will ensure appropriate further investigation and management, whether medical or surgical, which will positively affect the patient’s prognosis and outcome.