Diabetic ketoacidosis is an emergency medical condition that can be life- threatening if not treated properly. The incidence of this condition may be increasing, and a 1 to 2 percent mortality rate has stubbornly persisted since the 1970s. Diabetic ketoacidosis occurs most often in patients with type 1 diabetes (formerly called insulin-dependent diabetes mellitus); however, its occurrence in patients with type 2 diabetes (formerly called non-insulin-dependent diabetes mellitus), particularly in obese African Americans, is not as rare as was once thought. The management of patients with diabetic ketoacidosis includes obtaining a thorough but rapid history and performing a physical examination in an attempt to elucidate possible precipitating factors. The major treatment of this condition is initial rehydration (with isotonic saline) with subsequent potassium replacement and low-dose insulin therapy. The use of bicarbonate is not recommended in most patients. Cerebral edema, one of the most dire complications of diabetic ketoacidosis, occurs more commonly in children and adolescents than in adults. Continuous follow-up of patients using treatment algorithms and flow sheets can help to minimize adverse outcomes. Preventive measures include patient education and instructions for the patient to contact the physician early during an illness.

Diabetic ketoacidosis is a triad of hyperglycemia, ketonemia and acidemia, each of which may be caused by other conditions (Figure 1).1 Although diabetic ketoacidosis most often occurs in patients with type 1 diabetes (formerly called insulin-dependent diabetes mellitus), more recent studies suggest that it can sometimes be the presenting condition in obese black patients with newly diagnosed type 2 diabetes (formerly called non-insulin-dependent diabetes mellitus).2,3

The commonly used diagnostic criteria for diabetic ketoacidosis and average deficits of water and electrolytes are given in Table 1.4 The therapeutic regimen, which consists of replacing fluid and electrolyte losses and administering low-dose insulin, is based on an understanding of the pathogenesis of the condition. Even though protocols for the treatment of diabetic ketoacidosis are well established, a 1 to 2 percent mortality rate has persisted since the 1970s,5 emphasizing the need for careful, ongoing evaluation of this sometimes "rutine" medical emergency.

Major components of the pathogenesis of diabetic ketoacidosis are reductions in effective concentrations of circulating insulin and concomitant elevations of counterregulatory hormones (catecholamines, glucagon, growth hormone and cortisol).6 These hormonal alterations bring about three major metabolic events: (1) hyperglycemia resulting from accelerated gluconeogenesis and decreased glucose utilization, (2) increased proteolysis and decreased protein synthesis and (3) increased lipolysis and ketone production.7

Hyperglycemia initially causes the movement of water out of cells, with subsequent intracellular dehydration, extracellular fluid expansion and hyponatremia. It also leads to a diuresis in which water losses exceed sodium chloride losses. Urinary losses then lead to progressive dehydration and volume depletion, which causes diminished urine flow and greater retention of glucose in plasma. The net result of all these alterations is hyperglycemia with metabolic acidosis and an increased plasma anion gap.8

Evaluation of Patients with Diabetic Ketoacidosis

The history and physical examination continue to be important aspects of management. Even in comatose patients, information documenting a history of diabetes or insulin therapy may be available. The physical examination can provide supportive evidence for the diagnosis of diabetic ketoacidosis and can point to precipitating factors (Table 2).3,4

Although usually straightforward, the diagnosis of diabetic ketoacidosis is occasionally missed in unusual situations, such as when it is the initial presentation of diabetes in infants or elderly patients or when patients present with sepsis or infarction of the brain, bowel or myocardium. These presentations can distract the physician from the underlying diagnosis of diabetic ketoacidosis.

The laboratory tests needed to confirm the presence of diabetic ketoacidosis and to screen for precipitating events are summarized in Table 14 and Figure 2. The essential data can be obtained promptly in the emergency department.

By Tim Gorman

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