Diabetic ketoacidosis

Learning objectives

Diabetic ketoacidosis (DKA) is a potentially life-threatening complication of diabetes mellitus
DKA results from a relative or absolute insulin deficiency with an excess of hyperglycemic hormones (i.e., glucagon, catecholamines, cortisol, and growth hormone) leading to hyperglycemia because of increased gluconeogenesis, accelerated glycogenolysis, and impaired glucose use by peripheral tissues
DKA leads to lipolysis and the synthesis of ketoacids to use as fuel
Ketoacids trigger metabolic acidosis and polyuria, leading to severe dehydration
DKA occurs most often in patients with type 1 diabetes, but can also occur in patients with type 2 diabetes (rare)
Triggers include infection or inflammation (e.g., pneumonia, UTI, foot ulcer, abdominal [appendicitis, cholecystitis, pancreatitis]), inadequate insulin administration, myocardial infarction, stroke, certain medications (e.g., steroids, cocaine), pregnancy, and trauma

Most common complications are related to the treatment of DKA with fluids and electrolytes

Patients with DKA receive emergency treatment in the hospital, including:

Fluids

The average fluid deficit in DKA is 6 L
Start with 500-1500 mL of colloid bolus if clinically hypovolemic (hypotension, tachycardia)
Initial bolus should be normal saline (NS; 0.9% saline) bolus 10-15 mL/kg
Change to ½ NS with 20 mEq/L potassium after that
Replace ongoing intraoperative blood and fluid losses as usually
Change fluid to D5W with ½ NS if blood sugar drops to 250 mg/dL and anion gap is still present → allows insulin administration to reduce ketone without causing hypoglycemia

Insulin

Regular insulin 10 U IV bolus followed with an infusion at (blood glucose/150) U/h
Do not stop insulin if glucose <90, rather increase i.v. glucose administration
Consider changing to SQ insulin when the patient resumes P.O. alimentation

Electrolytes

Follow electrolytes closely every 4-6 h (every 2 h at the very beginning) until the anion gap closed
Potassium:
- 10-15 mEq/h for at least the first 4 h
- Irrespective of the initial potassium level, for a goal of 4–5 mEq/L
- Potassium will shift back to the intracellular compartment because of insulin and lead to hypokalemia if uncorrected
Phosphate: 1-2 mg/dL
Magnesium: 2 mEq/L

Acidosis

Triggering factors

Other

DKA is a life-threatening medical emergency characterized by the biochemical triad of ketonemia, hyperglycemia, and acidemia
Bedside monitoring of capillary ketones, glucose, blood gases, and electrolytes is used to make the initial diagnosis and guide management
Balanced electrolyte solutions resolve acidosis faster, but contain insufficient potassium to justify their safe use except in critical care
Continuation of long-acting insulins may reduce complications during the transition from i.v. to SQ insulin
Early involvement of diabetic specialist teams is required