College of Pharmacy
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HelixTalk Episode #43 - Review of Diabetic Ketoacidosis (DKA)
Date posted: May 17, 2016, 6:00 am
In this episode, we review the clinical presentation and treatment of diabetic ketoacidosis (DKA).
Key Concepts - Pathophysiology and Clinical Presentation
- DKA occurs mostly in type I diabetics and is usually precipitated by medication non-compliance or an acute stressor (such as an infection).
- The pathophysiology of DKA revolves around a deficiency of insulin, which causes poor cellular utilization of glucose. Cells utilize lipolysis as an alternative source of energy, which produces ketoacids like beta hydroxybutyrate and acetoacetic acid.
- Elevated blood glucose (due to poor cellular uptake) results in osmotic diuresis, dehydration, and a loss of electrolytes in the urine. As dehydration worsens, patients may have acute kidney injury and electrolyte disturbances.
- Elevated ketoacids causes nausea and vomiting (further contributing to dehydration), an anion gap metabolic acidosis, and the presence of ketones in the urine.
Key Concepts - Diagnosis and Treatment
- A diagnosis of DKA is made with an elevated blood glucose (above 250 mg/dL), an anion gap above 10, a serum bicarbonate level below 15 mEq/L, and a venous pH below 7.3. Ketones in the urine or ketoacids in the blood (like beta hydroxybutyrate) support the diagnosis of DKA.
- Hyperosmolar hyperglycemic state (HHS) is a variant of DKA that does not present with acidosis or ketosis. HHS patients typically have much higher blood glucose values (600-1000 mg/dL or more) with altered mental status. The treatment of DKA and HHS are very similar.
- Insulin is NOT the first-line therapy for DKA. Rehydration (several liters of a crystalloid like normal saline) and potassium repletion are the first two steps to management.
- As long as serum potassium is greater than 3.3 mEq/L, an insulin infusion is started. The 2009 ADA guidelines support either a bolus strategy (0.1 unit/kg bolus followed by 0.1 unit/kg/hr) or a no-bolus strategy (0.14 unit/kg/hr). Most institutions have a nursing-driven insulin titration protocol to manage the insulin rate based on blood glucose. Ideally, blood glucose values should reduce by 50-75 mg/dL per hour.
- Blood glucose usually normalizes before the anion gap is closed. In order to continue an insulin infusion to clear ketoacids from the blood, a dextrose source should be added once blood glucose reaches 250 mg/dL. Usually, the dextrose source is provided as D5W-NS (5% dextrose with 0.9% normal saline) or D5W-1/2NS (5% dextrose with 0.45% saline).
- Most patients with DKA will be admitted to an ICU for insulin drip titration. Typically, blood glucose and anion gap values normalize within 12-24 hours, indicating resolution of DKA. Once DKA is resolved, a basal subcutaneous insulin is given with an overlap of 1-2 hours with the insulin infusion.