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A diagnosis of diabetic ketoacidosis requires the patient's plasma glucose concentration to be above 250 mg per dL (although it usually is much higher), the pH level to be less than 7.30, and the bicarbonate level to be 18 mEq per L or less. Beta-hydroxybutyrate is a better measurement of the degree of ketosis than serum ketones. Intravenous insulin and fluid replacement are the mainstays of therapy, with careful monitoring of potassium levels. Phosphorous and magnesium also may need to be replaced. Bicarbonate therapy rarely is needed. Infection, insulin omission, and other problems that may have precipitated ketoacidosis should be treated. Myocardial infarction is a precipitating cause of diabetic ketoacidosis that is especially important to look for in older patients with diabetes. Cerebral edema is a major complication that occurs primarily in children. Education to prevent recurrence should be offered to all patients, including how to manage sick days and when to call a physician. (Am Fam Physician 2005;71:1705-14, 1721-2. Copyright© 2005 American Academy of Family Physicians.)
Many patients with diabetes die from diabetic ketoacidosis (DKA) every year. DKA is caused by reduced insulin levels, decreased glucose use, and increased gluconeogenesis from elevated counter regulatory hormones, including catecholamines, glucagon, and cortisol. DKA primarily affects patients with type 1 diabetes, but also may occur in patients with type 2 diabetes, and is most often caused by omission of treatment, infection, or alcohol abuse.1 Use of a standard protocol provides consistent results in treating DKA.2 An evidence-based guideline for the management of DKA from the American Diabetes Association (ADA) is the basis for much of this article.3
Initial Evaluation
Initial evaluation of patients with DKA includes diagnosis and treatment of precipitating factors (Table 1(4-18)). The most common precipitating factor is infection, followed by noncompliance with insulin therapy.3 While insulin pump therapy has been implicated as a risk factor for DKA in the past, most recent studies show that with proper education and practice using the pump, the frequency of DKA is the same for patients on pump and injection therapy.19
DIFFERENTIAL DIAGNOSIS
Three key features of diabetic acidosis are hyperglycemia, ketosis, and acidosis. The conditions that cause these metabolic abnormalities overlap. The primary differential diagnosis for hyperglycemia is hyperosmolar hyperglycemic state (Table 2(3,20)), which is...