Question 159

Question:

An 18-year-old female athlete reports easy fatigability and weakness. Physical examination shows no abnormalities. Laboratory studies are above. Which of the following is the most likely diagnosis?

Correct Answer: E.  Surreptitious use of diuretics

This patient’s serum bicarbonate is high, while her potassium is low. The potassium level in her urine is high. (Typical range is 50-150mEq per day). This indicates the use of a diuretic which blocks the reuptake of potassium.

Choice A is incorrect because aldosterone increases potassium secretion, therefore aldosterone deficiency would cause decreased potassium secretion.

Choice B is incorrect because hyperventilation causes respiratory alkalosis, resulting in decreased bicarbonate in the serum.

Choice C is incorrect because acidosis causes decreased potassium secretion. Also, diabetic ketoacidosis would cause additional symptoms and abnormally high blood glucose levels.

Choice D is incorrect because ingestion of anabolic steroids generally does not cause the type of potassium imbalance indicated by the lab values.