Endocrine Abstracts

Introduction: Lanreotide is a somatostatin analogue used in the treatment of acromegaly and pituitary adenomas expressing growth hormone (GH). We report a case of decompensated diabetes following the introduction of Lanreotide in a patient treated for a pituitary macroadenoma expressing GH.

Case report: A 64-year-old patient with a non-secreting pituitary macroadenoma, revealed by headaches and blindness of the left eye. The patient underwent surgery, and the immunohistochemical study demonstrated 80% positive labelling of the anti-GH antibody. The postoperative evaluation revealed that the macroadenoma persisted, with visual damage to the right eye. The decision was taken to treat the patient with Lanreotide on a medical basis. The patient’s preoperative work-up had revealed diabetes, and he was put on metformin. After three months of treatment with Lanreotide, the patient was admitted with an acid-ketotic decompensation without any precipitating factor. The patient was put on insulin therapy and Lanreotide was maintained in view of the endocranial improvement, with regular monitoring of glycaemic control during follow-up.

Discussion: The abnormalities in carbohydrate metabolism induced by somatostatin analogues are due to the inhibition of insulin and glucagon secretion by pancreatic β and α cells. This occurs via binding to somatostatinergic receptor subtypes, which in turn leads to the inhibition of incretin secretion. It should be noted that hyperglycaemia and diabetes are more frequent during treatment with Pasereotide, occurring early during the first three months of treatment. The effect of Lanreotide is minor and cases of induced diabetes are rare. It is therefore recommended that patients taking somatostatin analogues are monitored closely in terms of their carbohydrate parameters (self-monitoring of blood glucose levels, HbA1c at six weeks and then every three months), with treatment adapted according to blood glucose control.