Archive for the ‘The Dawn Phenomenon’ Category
Nancy Lydia Kimmel R.N., Ph.D., C.H.M.M.
Diabetes is an illness that the patient must live with the rest of their lives. The key to living with diabetes successfully is managing tight glycemic control, or controlling blood sugar levels. Blood sugar levels can vary from time to time depending on several factors such as stress levels, amount of food consumed, type of food consumed, amount of insulin used or insufficient insulin coverage and the time of day.
The human being responds to Circadian Rhythms. These are regular changes in mental and physical characteristics that occur in the course of a day. This term may be more familiar as the, “biological clock”. A good example is that of someone working midnights for the first time. They find it very difficult to sleep during the day and stay awake all through the night. It is as if their body has a mind of its own. In fact, there is some truth to that statement. Bears hibernate because of their biological clock.
Circadian Rhythms combined with the above mentioned factors can produce wide fluctuations in the blood glucose levels of diabetics while they sleep. A diabetic’s blood glucose level may be at 135 mg/dL prior to bedtime and at two A.M. may drop to 40 mg/dL, causing a severe state of hypoglycemia. The body responds to such a drop by producing glucose from alternate sources, since there is no source of ingested food. The only sources of glucose come from the liver via gluconeogenesis, lipolysis (break down of lipids) and glycogenolysis.
The body’s hormones stimulate this cascading response to dangerously low blood sugar. The results of such a response, is that of high blood sugar. This rebound hyperglycemia can in turn causes ketosis. Ketosis occurs because the body is fooled into thinking that there is not enough glucose, since the cells are starved, and the glucose is floating in the blood stream instead of being utilized within the cells. The body then begins to break down proteins which in turn cause the release of ketones. The release of ketones causes the pH of the system to drop. If the pH of the body drops below 7.35, a state of Diabetic Ketoacidosis occurs, which can cause a diabetic coma.
This rebound hyperglycemia known to occur in response to hypoglycemia in the early hours of the morning between two and four A.M., is called, the Somogyi Effect. A good way of detecting the Somogyi Effect is to have the diabetic test their blood sugar during those hours. If their blood sugar is low, then they can correct it by eating a snack, before going back to sleep.
The Somogyi Effect can occur at anytime during the day, but is most often equated with the early hours of the morning. Symptoms include headache, nightmares and night sweats. The treatment of this phenomenon usually involves lowering insulin dosage prior to sleep.
Another disorder similar to the Somogyi Effect is known as the Dawn Phenomenon. Although most diabetics are affected by this disorder, it seems to occur more often in pubescent adolescents. Adolescents’ blood sugar is affected adversely by their body releasing counter regulatory hormones. These counter regulatory hormones produce precipitously high blood sugar levels. It is thought that the growth hormone has some impact in relation to the production of counter regulatory hormones. Usually upon waking, the diabetic’s blood sugar is excessively high. Correction of the Dawn Phenomenon requires an increase in insulin coverage prior to bedtime.
It is easy to see how both of these disorders can be mistakenly diagnosed for the other. That is why it is important for the diabetic to test their own sugar on several early morning intervals and present the results to their doctor. Correct determination of which disorder is occurring is crucial to continued health of the diabetic.
- Lewis, Sharon., Heiitkemper, Margaret., Dirkesen, Shannon., Medical Surgical Nursing 6th ed., Copyright 2006, Mosby, St. Louis., pages 1273 -1278.
Tags: diabetes, nursing
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