All are features of Barters syndrome,except –
**Core Concept**
Bartter syndrome is a rare genetic disorder characterized by impaired salt reabsorption in the thick ascending limb of the loop of Henle, leading to hypokalemic metabolic alkalosis, hypercalciuria, and normal to low blood pressure. It is caused by mutations in genes encoding for proteins involved in sodium-potassium-chloride cotransporter (NKCC2) or other ion transporters.
**Why the Correct Answer is Right**
The correct answer features of Bartter syndrome include hypokalemia due to excessive potassium loss in the urine, metabolic alkalosis resulting from decreased hydrogen ion reabsorption, and hypercalciuria due to increased calcium excretion in the urine. These features are a direct consequence of the impaired salt reabsorption in the thick ascending limb of the loop of Henle.
**Why Each Wrong Option is Incorrect**
**Option A:** Hyperkalemia is incorrect because Bartter syndrome is characterized by hypokalemia, not hyperkalemia. The excessive potassium loss in the urine leads to decreased serum potassium levels.
**Option B:** Hypocalciuria is incorrect because Bartter syndrome is associated with hypercalciuria, not hypocalciuria. The increased calcium excretion in the urine is a hallmark of this disorder.
**Option C:** Normal blood pressure is incorrect because Bartter syndrome is often associated with low blood pressure, not normal blood pressure. The impaired salt reabsorption leads to volume depletion and decreased blood pressure.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that Bartter syndrome is a rare disorder that can mimic other conditions, such as Gitelman syndrome or primary aldosteronism, but the presence of hypercalciuria and normal to low blood pressure can help differentiate it from other causes of hypokalemia and metabolic alkalosis.
**Correct Answer:** A.