Selective proteinuria is typically seen in:
**Core Concept**
Selective proteinuria refers to the loss of albumin in the urine while the loss of larger molecules like blood and myoglobin is minimal. This condition is often associated with glomerular damage, specifically affecting the filtration barrier's size selectivity.
**Why the Correct Answer is Right**
The kidneys have a size-selective filtration barrier, which allows small molecules like albumin to pass through while restricting larger molecules like blood and myoglobin. In conditions like nephrotic syndrome, the glomerular basement membrane is damaged, allowing albumin to leak into the urine. However, the damage is selective, and the larger molecules are still restricted, resulting in selective proteinuria.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because minimal change disease is a type of nephrotic syndrome that affects the glomerular filtration barrier, leading to non-selective proteinuria.
**Option B:** This option is incorrect because focal segmental glomerulosclerosis (FSGS) is a type of nephrotic syndrome that also affects the glomerular filtration barrier, leading to non-selective proteinuria.
**Option C:** This option is incorrect because membranous nephropathy is a type of nephrotic syndrome that affects the glomerular filtration barrier, leading to non-selective proteinuria.
**Clinical Pearl / High-Yield Fact**
Nephrotic syndrome is characterized by heavy proteinuria (>3.5 g/24 hours), hypoalbuminemia, and edema. It can be caused by various conditions, including minimal change disease, focal segmental glomerulosclerosis, membranous nephropathy, and others.
**Correct Answer: C. Membranous nephropathy.**