MEDizzy - A 21-year-old male college student is evaluated for profound

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Disorders of Kidney and UTI

A 21-year-old male college student is evaluated for profound fatigue that has been present for several years but has recently become debilitating. He also reports several foot spasms and cramps, and occasional sustained muscle contractions that are uncontrollable. He is otherwise healthy, takes no medications, and denies tobacco or alcohol use. On examination he is well developed with normal vital signs including blood pressure. The remainder of the examination is normal. Laboratory evaluation shows a sodium of 138 meq/L, potassium of 2.8 meq/L, chloride of 90 meq/L, and bicarbonate of 30 mmol/L. Magnesium level is normal. Urine screen for diuretics is negative and urine chloride is elevated. Which of the following is the most likely diagnosis?

ExplanationThe patient presents with hypokalemia and hypochloremic metabolic alkalosis in the absence of hypertension. This is most commonly due to surreptitious vomiting or diuretic abuse, but in this case the urine diuretic screen was negative. In patients with surreptitious vomiting, urine chloride levels are low to pre - serve intravascular volume and this was not present in this patient. Those with Bartter’s syndrome and Gitelman’s syndrome have hypokalemia and hypochloremic metabolic alkalosis with inappropriately elevated urine chloride levels. Gitelman’s syndrome is less severe and presents later in life than Bartter’s, which is commonly found in child - hood due to failure to thrive. Additionally, those with Gitelman’s syndrome have more prominent fatigue and muscle cramping. Most forms of Bartter’s syndrome also include associated hypomagnesemia and hypocalciuria. Those with type 1 pseudohypoaldosteronism have severe renal salt wasting and hyperkalemia. Liddle’s syndrome presents with apparent aldosterone excess with severe hypertension, hypokalemia, and metabolic alkalosis