USMLE Step 1 Question 335

Question:

A 30-year-old woman known to have type 1 diabetes presents to the emergency room with a productive cough, fever, and polyuria for 4 days and progressive lethargy and confusion for the last day. She complains of abdominal pain and nausea with vomiting. Her breath smells fruity, her serum glucose is 600 mg/dL, and her serum potassium is 5.5. Initial management of this patient will likely include IV fluids, insulin, and which of the following?

Correct Answer: E.  Potassium

This woman is likely in diabetic ketoacidosis. She needs urgent IV fluids, insulin, and potassium. Despite a mildly elevated serum potassium her total body potassium stores are low. Administration of insulin will drive potassium into cells and decrease her serum potassium.