Lesson of the month 2: Houssay phenomenon - hypopitutarism leading to remission of diabetes.

Because of a pituitary insult and the subsequent loss of counter-regulatory hormones, individuals can experience increased sensitivity to insulin, hypoglycaemia or even complete amelioration of diabetes; this is known as the Houssay phenomenon. Severe dehydration following diarrhoea can lead to pituitary infarction causing hypopituitarism. We describe this situation in a patient with insulin-treated type-2 diabetes presenting with recurrent hypoglycaemia and cessation of insulin requirement along with weight loss, hypotension and hyponatraemia. Pituitary imaging revealed a partial empty sella and a synacthen stimulation test revealed an initial positive response but later loss of response, proving recent-onset pituitary dysfunction. Physicians should keep this possibility in mind while treating hypoglycaemia in stable diabetic individuals. Judicious supplementation of deficient hormones is of utmost importance.