Diabetic Ketoacidosis (DKA): Pathophysiology and Treatment

Diabetic Ketoacidosis is a state of absolute or relative insulin deficiency aggravated by ensuing hyperglycemia, dehydration, and acidosis-producing derangements in intermediary metabolism, including the production of serum acetone.

It can occur in both Type I Diabetes and Type II Diabetes
In type II diabetics with insulin deficiency/dependence.
The presenting symptom for ~ 25% of Type I Diabetics.

Causes of Diabetic Ketoacidosis

The stressful precipitating event that results in increased catecholamines, cortisol, glucagon.
Infection (pneumonia, UTI)
Alcohol, drugs
Stroke
Myocardial Infarction
Pancreatitis
Trauma
Medications (steroids, thiazide diuretics)
Non-compliance with insulin

Essentials of diagnosis OF DKA

Acidosis with blood pH <7.3
Serum bicarbonate < 15mEq/L
Serum positive for ketones
Elevated anion gap
Variable, may occur without a gap.
Hyperglycemia > 250

No correlation between the severity of hyperglycemia and severity of ketoacidosis

Clinical manifestations of diabetic ketoacidosis

History

polydipsia and urination

Nausea and vomiting

Generalized weakness and fatigability

Altered consciousness is common (stupor or coma).

Symptoms of associated intercurrent illness

Physical Assessment findings

Signs of dehydration -tachycardia, hypotension.

Acetone odor(fruity breath odor)

Signs of acidosis

Shallow rapid breathing or air hunger (Kussmaul or sighing respiration)

Abdominal tenderness and abdominal pain.

Disturbance of consciousness

Signs of intercurrent illness.

Mild Hypothermia.

Diabetic Ketoacidosis Treatment

Management of DKA includes:

1) Fluids
2) Insulin
3) Electrolyte replacement.

Fluid replacement

Glucose osmotic diuresis causes dehydration therefore in your management you should give between 4-6 liters, then reassess (caution in CHF). Fluids help decrease blood glucose levels.

Always start with isotonic normal saline fluids. Give as a bolus and then a steady rate (i.e. 150cc/hr). Switch to 0.45% NS when “corrected” sodium within normal limits.

Add 1.6 mEq to sodium for every 100 glucose is above 100. Switch to Dextrose 5% 1/2 Normal Saline when glucose between 200-250.

Insulin

Administer intravenous insulin drip as a bolus approx 10 units (or 0.1 to o.15 units/kg), then initiate drip at 0.1 unit/kg/hr. Ideally, you should decrease glucose 50-100 mg/dl per hour. Avoid bolus if the potassium level is above 3.3mEq.

Replete potassium before starting a drip. Insulin drives potassium into the cells so if potassium starts off very low can make hypokalemia life-threatening.

Switch to subcutaneous insulin when the anion gap closed signifying acidosis cleared.

Subcutaneous insulin must overlap with an insulin drip over 2 hours. Use the patient’s outpatient insulin dose several hours prior to stopping the insulin drip or In insulin-naive patients, a multi-dose insulin regimen should be started at a dose of 0.5 to 0.8 U/kg per day, including bolus and basal insulin until an optimal dose is established OR

Calculate 24-hour insulin requirements and use 50% as long-acting. Once the anion gap closes, can feed the patient. Remember to add sliding scale insulin (preferably lispro) with meals in addition to basal SC insulin dose.

Electrolyte replacement

Bicarbonate: If pH<6.9 (controversial) or K>6 with ECG changes

Potassium: If potassium < 5.3, you give 20-60 meq/L of ½ normal saline when K <5.3 with severe acidosis

Phosphate: If phosphate is below 1, especially if muscle weakness. When needed 20-30mEQ/L of potassium phosphate can be added to replacement fluids. Be sure to check q1hour glucose checks and q2-4hrs BMP to monitor anion gap and acidosis

Pitfalls of diabetic ketoacidosis treatment

High serum glucose levels may lead to dilutional hyponatremia

Triglyceride levels may lead to fictitious low glucose;

High levels of ketone bodies may lead to factitious elevation of creatinine.

Potassium replacement

If the potassium level is greater than 6 mEq/L, do not administer potassium supplementation.

If the potassium level is 4.5-6 mEq/L, administer 10 mEq/h of potassium chloride.

If the potassium level is 3-4.5 mEq/L, administer 20 mEq/h of potassium chloride. Monitor serum potassium levels hourly, and the infusion must stop if the potassium level is greater than 5 mEq/L.