Clinical Case Study
Severe and recurrent hypoglycemia in a patient with type 1 diabetes: importance of screening for integrity of counter-regulatory hormonal secretion
Diabetic Hypoglycemia June 2012, Volume 5, Issue 1: page 9-11
A 39-year-old woman with type 1 diabetes since 1995 had been treated with continuous subcutaneous insulin infusion since a pregnancy in 1997. She had developed lymphocytic hypophysitis postpartum, which had been thought to have resolved spontaneously. She had no complications of diabetes but had developed impaired awareness of hypoglycaemia (IHA) and frequently experienced episodes of severe hypoglycemia requiring assistance. Clinical recommendations to adjust insulin doses were followed meticulously by the patient.
At initial review, pituitary function superficially appeared to be normal, with normal plasma concentrations of gonadotrophins, thyroid-stimulating hormone and cortisol, and a normal response to a 250 μg synacthen test. However, plasma insulin-like growth factor-1 was low (26 ng/ml). Pituitary magnetic resonance imaging was normal. An insulin-induced hypoglycemia test showed a total absence of responses of growth hormone (GH), adrenocorticotropic hormone (ACTH) and cortisol. A GH-releasing hormone test confirmed the presence of GH deficiency and a 1 μg synacthen test revealed adrenal insufficiency. Replacement therapy with GH and hydrocortisone was therefore recommended.
Although the present case illustrates the role of subclinical hypopituitarism in provoking recurrent hypoglycemia, cortisol and GH insufficiencies may co-exist in people with diabetes who have IHA, and may need to be actively sought through testing of pituitary function.
Keywords: hypoglycemia, diabetes, impaired hypoglycemia awareness, counter-regulatory hormonal insufficiencies, adrenal insufficiency