Decrease in GFR is apparent in which of the following stages of Chronic Kidney Disease
**Core Concept**
Chronic Kidney Disease (CKD) is a progressive loss of kidney function, and its staging is crucial for assessing the severity of the disease. The Glomerular Filtration Rate (GFR) is a key parameter used to measure kidney function, and its decrease is a hallmark of CKD.
**Why the Correct Answer is Right**
The decrease in GFR is apparent in the early stages of CKD, specifically in Stage 3. This is because even a small decrease in GFR can indicate a significant loss of kidney function. In Stage 3 CKD, the GFR is typically between 30-59 mL/min/1.73m^2, which is a significant reduction from the normal value of 90 mL/min/1.73m^2. The decrease in GFR is due to the loss of nephrons, which are the functional units of the kidney responsible for filtering waste and excess fluids from the blood.
**Why Each Wrong Option is Incorrect**
* **Option A:** This is incorrect because Stage 1 CKD typically has a normal or slightly elevated GFR, and the decrease is not apparent until later stages.
* **Option B:** This is incorrect because Stage 5 CKD, also known as End-Stage Renal Disease (ESRD), is characterized by a very low GFR, typically less than 15 mL/min/1.73m^2, and is the most severe stage of CKD.
* **Option D:** This is incorrect because Stage 2 CKD typically has a GFR between 60-89 mL/min/1.73m^2, which is still within the normal range, and the decrease in GFR is not apparent until later stages.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the decrease in GFR is a gradual process, and it may take several years for the GFR to decrease significantly. Therefore, early detection and management of CKD are crucial to prevent progression to more severe stages of the disease.
**Correct Answer:** C.