Board Review: Diabetic Ketoacidosis and Total Body Potassium
A 23 y/o M with a PMHx of Type 1 DM arrives to your ED reporting nausea, vomiting and elevated blood sugars on his home monitor. His initial blood work indicates he is in DKA. For which of the following potassium levels should initiation of an insulin drip be delayed for potassium repletion?
(scroll down for the answer)
a) < 3.0 mEq/L
b) < 3.3 mEq/L
c) < 3.5 mEq/L
d) < 3.8 mEq/L
e) < 4.0 mEq/L
The correct answer is b) < 3.3 mEq/L
Following the American Diabetes Association guidelines for the treatment of DKA, patients with hypokalemia on initial labs of 3.3 mEq/L or less must have potassium replacement with a delay in insulin treatment until the potassium concentration is restored to > 3.3 mEq/L
Patients in DKA are low in total body potassium and their serum concentration is falsely elevated due to extracellular shift. On average, patients will have a potassium deficit of 3-5 mEq/kg. Treatment with insulin will cause a shift of potassium intracellularly which can lead to severe hypokalemia and cardiac dysrhythmia.
All DKA patients will require potassium replacement to prevent hypokalemia. Generally 20mEq of potassium in each liter of fluid given will maintain a normal serum potassium concentration.
The ADA Guidelines for DKA can be found here: http://care.diabetesjournals.org/content/32/7/1335
A Core review of Hypokalemia in the ED was recently posted on emDOCs by Dr. Swaminathan, see it here: http://www.emdocs.net/core-em-hypokalemia/