Somogyi Effect

Ok, so what is the Somogyi effect? Jayne Leonard wrote an article about the Somogyi effect that was reviewed by Alana Biggers, MD, MPH that gives us more information about the causes and prevention of the Somogyi effect, also known as the rebound effect, that occurs in people with diabetes.

Low blood glucose or hypoglycemia in the late evening causes a rebound effect in the body that leads to hyperglycemia or high blood glucose in the early morning. This Somogyi effect is widely reported but still controversial because of a lack of scientific evidence. People with type 1 diabetes report this more than those with type 2 diabetes.

Somogyi effect is named after Michael Somogyi who is a Hungarian-born researcher who first described it as the body’s defense response to prolonged periods of low blood sugar. Having a dose of insulin before bed that is too high can be a cause of this effect. Insulin reduces the amount of glucose in the blood by too much and causes hypoglycemia. Then the hypoglycemia makes the body stressed and triggers to release of the stress hormones epinephrine, cortisol and growth hormone. Then the endocrine hormone glucagon is also released. Glucagon triggers the liver to convert glycogen into glucose that can send the blood glucose levels into a rebound high. Stress hormones keep the blood glucose levels raised by making the cells less responsive to insulin, thus creating the condition as insulin resistance.

This condition is widely known among doctors and those with diabetes, but little scientific evidence is available for the theory. One study found hyperglycemia is likely to be caused by not enough insulin before bed, upon waking in the morning. Those who appeared to have rebound hyperglycemia had no higher levels of growth hormone, cortisol or glucagon than others. Another study in 2007 of 88 people with type 1 diabetes using continuous glucose monitoring found that those who experienced hyperglycemia after waking had not experienced hypoglycemia at nighttime and the Somogyi effect was not present. Yet others cite the Somogyi effect as a common cause of morning time hyperglycemia in people with type 1 diabetes.

The dawn phenomenon, or dawn effect, and the Somogyi effect are similar but the reasons for the hyperglycemia differ. The results of the dawn effect are from a rise in early-morning blood sugar levels that are triggered by declining levels of insulin and an increase in growth hormones. You can distinguish the difference between the Somogyi effect and the dawn phenomenon by testing blood sugar levels at 3 a.m. and again in the morning. Low blood sugar at 3 a.m. indicates the Somogyi effect and high or normal blood sugar at the time suggests the dawn phenomenon. The dawn phenomenon is considered more common than the Somogyi effect, but there is some research that indicates the Somogyi effect is the biggest cause of fasting hyperglycemia in people with type 1 diabetes.

Some symptoms of the Somogyi effect include low blood glucose levels at 2 a.m. or 3 a.m., night sweats, rapid heart rate, waking with a headache, blurred vision, confusion, dizziness, dry mouth, fatigue, increased appetite, and thirst. This effect is seen in those with diabetes who use insulin therapy to manage their condition. Taking too much insulin and not eating enough before bed cause it. Both can cause blood glucose levels to fall too low.

Frequent glucose monitoring with a glucose monitoring system will be helpful and can help to confirm the diagnosis over time and help the management of hypoglycemic unawareness. Some treatment options are adjusting the timing of insulin administration, lowering the dose of insulin taken before bed, changing the type of insulin used, eating a snack with evening insulin dosage and taking into account lifestyle factors, such as stress and exercise. A CGM system can alert people to hypoglycemia or hyperglycemia through the use of alarms.

Outlook is excellent if the Somogyi effect is properly identified and managed. Those experiencing these effects should discuss the issue with their doctor before making any changes to their insulin regimen. Just remember that diet, exercise and other lifestyle factors also affect the outlook for those with diabetes and the Somogyi effect.

Dr Fredda Branyon