Test Your Knowledge Answer #395

This patient has developed clinical and biochemical evidence to support a diagnosis of adrenal insufficiency (Addison's disease), which occurs with increased frequency in patients who have type 1 diabetes (autoimmune polyglandular endocrinopathy syndrome). Adrenal insufficiency often results in an increase in insulin sensitivity because of the decrease in circulating glucocorticoids, which are “anti-insulin” hormones. This effect may result in an increase in the frequency of hypoglycemia.

 

The most common causes of hypoglycemia in type 1 diabetes are mismatches between insulin and food ingestion or between insulin and physical activity. This patient has no history of an increase in exercise or a change in meal plan. Achievement of tight glycemic control is also associated with an increased frequency of hypoglycemia, which again is related to a mismatch between insulin pharmacokinetics, food intake, and exercise. Renal insufficiency is another cause of increased hypoglycemia in patients with this disease—the metabolism of insulin is decreased, leading to longer biological effects of the hormone. No data support renal insufficiency in this patient, however, and the clinical presentation resembles that of Addison's disease. Finally, the clinical picture does not fit a diagnosis of thyrotoxicosis, which is not associated with an increased frequency of hypoglycemia.