Abstract
A 43-year-old man was diagnosed with acromegaly due to pituitary GH-secreting macroadenoma, and underwent craniotomy surgery. After surgery, he was given octreotide long-acting release (LAR) to treat the residual tumor. Eighteen months later, he presented polydipsia and polyuria due to diabetic ketoacidosis (DKA) and central diabetes insipidus (CDI). His casual plasma glucose level was 570 mg/dL, his HbA1c was 14.9%, and his urine was strongly positive for ketone bodies. We discuss a causal relationship among DKA, CDI, and treatment with LAR in this case with residual GH-secreting tumor from the perspective of insulin secretion and resistance.