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).

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Key Concepts - Pathophysiology and Clinical Presentation

1. DKA occurs mostly in type I diabetics and is usually precipitated by medication non-compliance or an acute stressor (such as an infection).
2. 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.
3. 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.
4. 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

1. 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.
2. 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.
3. 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.
4. 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.
5. 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).
6. 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.

For additional information, see the 2009 ADA Hyperglycemic Crises in Adult Patients guidelines (PubMed, free full text)