What is the pathophysiology behind the dawn phenomenon and how is it managed?

• A. Early morning hepatic glucose production driven by circadian hormones; managed by adjusting evening insulin or bedtime snack.
• B. Nocturnal hypoglycemia triggers morning hyperglycemia
• C. Increased intestinal glucose absorption overnight
• D. Increased morning insulin sensitivity

Answer: (A)

Dawn phenomenon happens when the liver increases glucose production in the early morning due to circadian release of hormones like growth hormone and cortisol, which also momentarily reduce insulin effectiveness. This combination leads to a rise in fasting glucose before you wake up. The best way to manage it is by ensuring adequate insulin action during the predawn hours—most often by adjusting the evening basal insulin dose or its timing (so the body has enough insulin to suppress hepatic glucose output during those hours). A bedtime snack can be a consideration in some plans to shape overnight glucose, but the key fix is normally how the overnight insulin is scheduled and dosed. It’s helpful to contrast this with the somogyi effect, where morning hyperglycemia results from overnight hypoglycemia triggering rebound glucose production, which has a different management approach.