What is the Somogyi effect and how does it differ from the dawn phenomenon?

The Somogyi effect is rebound hyperglycemia that occurs when a nocturnal hypoglycemic episode triggers counter-regulatory hormones like glucagon, cortisol, and epinephrine, causing blood glucose to spike by morning. Treatment involves reducing the evening insulin dose or adding a bedtime snack. The dawn phenomenon is early-morning hyperglycemia caused by the normal physiological release of growth hormone and cortisol between 4 and 8 AM, without preceding hypoglycemia. Treatment involves adjusting the timing or dose of evening insulin.