In an adult Unilateral smooth contracted kidney with hypeension is seen in –
**Core Concept**
In an adult unilateral smooth contracted kidney with hypertension, the underlying pathophysiological principle involves the renin-angiotensin-aldosterone system (RAAS). The RAAS plays a crucial role in regulating blood pressure, and abnormalities in this system can lead to hypertension. The smooth contracted kidney is often associated with chronic kidney disease, which may be caused by various factors.
**Why the Correct Answer is Right**
The correct answer is related to the activation of the RAAS due to decreased renal perfusion in the contracted kidney. This leads to increased renin release by the juxtaglomerular cells, resulting in the conversion of angiotensinogen to angiotensin I, which is then converted to angiotensin II by angiotensin-converting enzyme (ACE). Angiotensin II causes vasoconstriction and stimulates the release of aldosterone, leading to sodium retention and increased blood pressure. This mechanism is a classic example of the RAAS-mediated hypertension.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a condition that is directly related to the pathophysiology of a unilateral smooth contracted kidney with hypertension. While polycystic kidney disease (PKD) can cause hypertension, it is not the most direct association with a unilateral smooth contracted kidney.
**Option B:** This option is incorrect because it does not accurately describe the pathophysiological mechanism underlying a unilateral smooth contracted kidney with hypertension. While renovascular disease can cause hypertension, it is not the most direct association with a unilateral smooth contracted kidney.
**Option C:** This option is incorrect because it does not accurately describe the pathophysiological mechanism underlying a unilateral smooth contracted kidney with hypertension. While chronic kidney disease can cause hypertension, it is not the most direct association with a unilateral smooth contracted kidney.
**Clinical Pearl / High-Yield Fact**
In patients with a unilateral smooth contracted kidney and hypertension, it is essential to consider the possibility of renovascular disease, such as stenosis of the renal artery, as a potential cause of the hypertension. This is because the RAAS-mediated hypertension in this scenario may be due to decreased renal perfusion, which can be caused by renovascular disease.
**Correct Answer:** C.