Diabetic ketoacidosis (DKA) is a very serious complication of diabetes mellitus, a metabolic disorder that is characterized by hyperglycemia, metabolic acidosis, and increased body ketone concentrations. The most common causes of DKA are infection and poor compliance with medication regimens. Other causes include undiagnosed diabetes, alcohol abuse, and a multitude of medical conditions such as cerebrovascular accident (CVA), complicated pregnancy, myocardial infarction, pancreatitis, and stress. Diabetic ketoacidosis is a complicated pathology. Early recognition of DKA, a good understanding of the pathological processes of DKA, and aggressive treatment are the keys to successful treatment. With good care, DKA can be managed and the patient will survive.
When the student has finished studying this module, he/she will be able to:
1. Identify the correct definition of DKA.
2. Identify a basic function of insulin.
3. Identify the insulin derangements of types I and II diabetes. 4. Identify the basic cause of DKA.
5. Identify two specific causes of DKA.
6. Identify the two pathogenic mechanisms that produce the signs/symptoms of DKA. 7. Identify metabolic consequences of increased hormone concentrations in DKA. 8. Identify the criteria used to diagnose DKA.
9. Identify common signs and symptoms of DKA.
10. Identify laboratory abnormalities seen in DKA.
11. Identify complications of DKA.
12. Identify the three most important therapies for treating DKA. 13. Identify the correct roles of sodium bicarbonate and phosphate in treating DKA. 14. Identify an important rule for using potassium replacement in DKA. 15. Identify an important rule for switching from IV to subcutaneous insulin.
Most cases of DKA are seen in patients with type I diabetes, but approximately 10%-30% of all cases of DKA occur in patients with type II diabetes.1 The incidence of DKA appears to be rising, and this may not be related to the well publicized increase in the incidence of diabetes that has become a serious public health problem.2 Diabetic ketoacidosis accounts for 50% of all diabetes-related admissions in young people with the disease, and DKA is the most common cause of diabetes-related death in children and adolescents with type I diabetes.3 Diabetic ketoacidosis is much more common in children than in adults, it is more common in women than in men, and it is more common in Caucasians.4 The exact incidence of death from DKA is not known, but it has been estimated to be between 1%-10%.5 Survival depends on the severity of the case, the age of the patient, the presence/absence of certain medical conditions, and how quickly DKA is recognized and how effectively it is treated. If the condition is promptly diagnosed and properly treated, the mortality rate can be 250 mg/dL) metabolic acidosis (blood pH ≤ 7.30) and an elevated level of serum ketones (> 5 mEq/L) and/or ketones in the urine.11 Patients will also have an anion gap (Na+ - Cl- + HCO3-), an elevated blood urea nitrogen (BUN), hyponatremia, hyperkalemia, and the serum amylase may be elevated. The total body phosphate level may be low but the serum level may be normal or elevated. At this time, there is no universally agreed upon consensus for the diagnostic criteria of DKA, and some sources feel that an anion gap > 10-12 mEq/L and serum bicarbonate (HCO3) ≤ 18 mEq/L should be part of the criteria.
Learning Break: Some authors feel that most important test for diagnosing DKA is total blood ketone concentration.12,13
The acidosis and hyperglycemia of DKA and the electrolyte changes that are so commonly seen in DKA are closely related. The shift in metabolism and the high concentration of acidic ketones seen in cases of DKA produces a metabolic acidosis. Acidosis and insulin deficiency causes potassium to shift from the intracellular space to the extracellular space and serum...