A 17-year-old white female comes to the office for the evaluation of fatigue which has been present for the past 4 months. Her past medical history is insignificant. She denies the use of any drugs. Her pulse is 74/min, blood pressure is 110/70 mm Hg, and temperature is 36.7° C (98.0° F). Physical examination shows scars on the dorsum of her hands and dental erosions. Laboratory studies show: Urine chloride concentration is 15 mEq/L (Normal = 80-250 mEq/L). Based on these findings, what is the most likely diagnosis?

Question

A 17-year-old white female comes to the office for the evaluation of fatigue which has been present for the past 4 months.  Her past medical history is insignificant.  She denies the use of any drugs.  Her pulse is 74/min, blood pressure is 110/70 mm Hg, and temperature is 36.7° C (98.0° F).  Physical examination shows scars on the dorsum of her hands and dental erosions.  Laboratory studies show:  Urine chloride concentration is 15 mEq/L (Normal = 80-250 mEq/L).  Based on these findings, what is the most likely diagnosis?

Quizplus · Accepted Answer

Suspect the following conditions whenever a patient presents with hypokalemia, alkalosis and normotension: Surreptitious vomiting Diuretic abuse Bartter syndromeGitelman's syndrome Surreptitious vomiting Diuretic abuse Bartter syndrome Gitelman's syndrome Physical findings that are characteristic of surreptitious vomiting are scars/calluses on the dorsum of the hands, and dental erosions. The dorsal scars result from repeated chemical/mechanical injury as the patient uses his/her hands to induce vomiting. Dental erosions result due to increased exposure to gastric acid. Surreptitious vomiting may also result in hypovolemia and hypochloremia, which in turn lead to a low urine chloride concentration. (Choice B and E) Patients with diuretic abuse and Bartter/Gitelman's syndrome may also present with hypokalemia, alkalosis and normotension, but their urine chloride concentrations are high. Patients with diuretic abuse may give a history of diuretic abuse and have a positive urine assay for diuretics. (Choice A) Patients with chronic diarrhea have metabolic acidosis and hypokalemia. Metabolic acidosis occurs due to the loss of bicarbonate in the stool. (Choice D) Patients with primary hyperaldosteronism have hypokalemia, metabolic alkalosis and hypertension. Educational Objective: Always suspect surreptitious vomiting as a cause of hypokalemic alkalosis in a normotensive patient, and be able to distinguish it from other entities (e.g., diuretic abuse, Bartter's syndrome) using the urine chloride concentration.

A 17-Year-Old White Female Comes to the Office for the Evaluation