Recurrent Hypoglycemia in Diabetic Patient With Hypopituitarism: The Houssay Phenomenon

The association of treatment of diabetes mellitus and hypoglycemia is well described in the literature. However, the association of recurrent hypoglycemia in diabetic patients with hypopituitarism has been rarely described. This phenomenon, called Houssay phenomenon, usually occurs in individuals with a long diabetes evolution. It is caused by the failure of counter-regulatory hormones produced by the anterior pituitary gland to correct hypoglycemia. We describe this phenomenon in an elderly female known with type 2 diabetes mellitus taking insulin and oral diabetes medications. Workup showed partially empty sella on pituitary imaging. Hormonal assessment showed very low morning cortisol, low adrenocorticotropin hormone (ACTH) and zero response to synacthen. Loss of these counter-regulatory hormones leads to hypoglycemia (Houssay phenomenon). Hypopituitarism has several causes, including pituitary adenoma and traumatic brain injury as common causes among the others. In our reported case, we correlate our patient’s condition to Houssay phenomenon, for the implication of refractory hypoglycemic episodes and cortisol deficiency, all of which are the consequences of hypopituitarism. Clinicians should be aware of the link between diabetes and hypopituitarism to avoid deleterious consequences of hypoglycemia.