Diabetic ketoacidosis is a dangerous complication of diabetes mellitus in which the chemical balance of the body becomes far too acidic.
Description
Diabetic ketoacidosis (DKA) always results from a severe insulin deficiency. Insulin is the hormone secreted by the body to lower the blood sugar levels when they become too high. Diabetes mellitus is the disease resulting from the inability of the body to produce or respond properly to insulin, required by the body to convert glucose to energy. In childhood diabetes, DKA complications represent the leading cause of death, mostly due to the accumulation of abnormally large amounts of fluid in the brain (cerebral edema). DKA combines three major features: hyperglycemia, meaning excessively high blood sugar kevels hyperketonemia, meaning an overproduction of ketones by the body; and acidosis, meaning that the blood has become too acidic.
Insulin deficiency is responsible for all three conditions: the body glucose goes largely unused since most cells are unable to transport glucose into the cell without the presence of insulin; this condition makes the body use stored fat as an alternative source instead of the unavailable glucose for energy, a process that produces acidic ketones, which build up because they require insulin to be broken down. The presence of excess ketones in the bloodstream in turn causes the blood to become more acidic than the body tissues, which creates a toxic condition.
Causes and symptoms
DKA is most commonly seen in individuals with type I diabetes, under 19 years of age and is usually caused by the interruption of their insulin treatment or by acute infection or trauma. A small number of people with type II diabetes also experience ketoacidosis, but this is rare given the fact that type II diabetics still produce some insulin naturally. When DKA occurs in type II patients, it is usually caused by a decrease in food intake and an increased insulin deficiency due to hyperglycemia.
Diagnosis requires the demonstration of hyperglycemia, hyperketonemia, and acidosis. DKA is established if the patient's urine or blood is strongly positive for glucose and ketones. Normal glucose levels in a non-diabetic person on average range from 80–110 mg/dl. A person with diabetes will typically fluctuate outside those parameters. DKA glucose levels exceed 250 mg/dl and can reach 400 to 800 mg/dL. A low serum bicarbonate level (usually below 15 mEq/L) is also present, indicative of acidosis.
A blood test or urinalysis can quickly determine the concentration of glucose in the bloodstream. Test strips are available to patients commercially can sub-merge in urine to detect the presence or concentration of ketones.
Treatment
Ketoacidosis is treated under medical supervision and usually in a hospital setting.
Basic treatment includes:
administering insulin to correct the hyperglycemia and hyperketonemia
Replacing fluids intravenously lost through excessive urination and vomiting
Balancing electrolytes to re-establish the chemical equilibrium of the blood and prevent potassium deficiency (hypokalemia) during treatment
With proper medical attention, DKA is almost always successfully treated. The DKA mortality rate is about 10%. Coma on admission adversely affects the prognosis. The major causes of death are circulatory collapse, hypokalemia, infection, and cerebral edema.
Prevention
Once diabetes has been diagnosed, prevention measures to avoid DKA include regular monitoring of blood glucose, administration of insulin, and lifestyle maintenance. Glucose monitoring is especially important during periods of stress, infection, and trauma when glucose concentrations typically increase as a response to these situations. Ketone tests should also be performed during these periods or when glucose is elevated.
BOOKS
Saudek, Christopher D., Richard R. Rubin, and Cynthia S. Shump. The Johns Hopkins Guide to Diabetes. Baltimore: The Johns Hopkins University Press, 1997.
ORGANIZATIONS
American Diabetes Association. 1701 North Beauregard Street, Alexandria, VA 22311.(800)-342-2383. <http://www.diabetes.org/>.
Juvenile Diabetes Foundation. 120 Wall St., New York, NY 10005. (800) 533-CURE. <http://www.jdf.org/>.
National Institute of Diabetes and Digestive and Kidney Disorders (NIDDK). 31 Center Drive, MSC 2560, Bethesda, MD 20892-2560. <http://www.niddk.nih.gov>.
Gary Gilles
KEY TERMS
Acidosis—A condition that causes the pH of the blood to drop and become more acidic.
Diabetes mellitus—Disease characterized by the inability of the body to produce or respond properly to insulin, which is required by the body to convert glucose to energy.
Edema—The presence of abnormally large amounts of fluid in the intercellular tissue spaces of the body.
Glucose—The type of sugar found in the blood.
Hyperglycemia—Condition characterized by excessively high levels of glucose in the blood, and occurs when the body does not have enough insulin or cannot use the insulin it does have to turn glucose into energy. Hyperglycemia is often indicative of diabetes that is out of control.
Hyperketonemia—Condition characterized by an overproduction of ketones by the body.
Hypoglycemia—Lower than normal levels of glucose in the blood.
Hypokalemia—A deficiency of potassium in the blood.
Insulin—A hormone secreted by the pancreas in response to high blood sugar levels that induces hypoglycemia. Insulin regulates the body's use of glucose and the levels of glucose in the blood by acting to open the cells so that they can intake glucose.
Ketones—Poisonous acidic chemicals produced by the body when fat instead of glucose is burned for energy. Breakdown of fat occurs when not enough insulin is present to channel glucose into body cells.
Lactic acidosis—A serious condition caused by the build up of lactic acid in the blood, causing it to become excessively acidic. Lactic acid is a by-product of glucose metabolism.
Metabolism—The sum of all chemical reactions that occur in the body resulting in growth, transformation of foodstuffs into energy, waste elimination and other bodily functions.
Polyuria—Excessive secretion of urine.
Type I diabetes—Also called juvenile diabetes. Type I diabetes typically begins early in life. Affected individuals have a primary insulin deficiency and must take insulin to stay alive.
Type II diabetes—Type II diabetes is the most common form of diabetes and usually appears in middle aged adults. It is often associated with obesity and may be delayed or controlled with diet and exercise.
