“Squatting attacks” and polycythemia are features of?
**Core Concept**
Squatting attacks and polycythemia are manifestations of a specific underlying condition that affects the kidneys and the body's ability to regulate red blood cell production.
**Why the Correct Answer is Right**
Squatting attacks are characteristic of renal artery stenosis, which leads to increased renin production. This results in vasoconstriction of the lower limb arteries, causing pain in the calves or thighs, particularly when squatting or walking. The increased renin activity also stimulates the production of erythropoietin, leading to polycythemia. This is because the kidneys are unable to adequately filter waste products, including excess hemoglobin, resulting in an increase in red blood cell mass.
**Why Each Wrong Option is Incorrect**
* **Option A:** This condition is not typically associated with squatting attacks or polycythemia.
* **Option B:** While this condition can lead to hypertension, it is not directly associated with squatting attacks or polycythemia.
* **Option C:** This condition is primarily associated with hypokalemia and metabolic alkalosis, not squatting attacks or polycythemia.
**Clinical Pearl / High-Yield Fact**
Renal artery stenosis can be a cause of secondary hypertension and should be considered in patients with unexplained hypertension, particularly if they have a history of atherosclerotic disease or are taking medications that can exacerbate hypertension.
**Correct Answer:** C.