Spider leg appearance in IVP is suggestive of ?
**Core Concept**
The "spider leg" appearance in an Intravenous Pyelogram (IVP) is a radiological sign that indicates a specific type of kidney stone or ureteral pathology. This appearance is characterized by the presence of multiple, thin, radiopaque lines radiating from a central point, resembling the legs of a spider.
**Why the Correct Answer is Right**
The spider leg appearance is typically seen in cases of ureteral obstruction caused by a ureteral stone, which is commonly a staghorn calculus. The staghorn calculus is a type of kidney stone that fills the renal pelvis and extends into the calyces, giving it a characteristic branching or staghorn shape. As the stone grows, it can cause ureteral obstruction, leading to the characteristic radiographic appearance of multiple, thin, radiopaque lines radiating from the stone, resembling the legs of a spider. This appearance is due to the stone's irregular shape and the resulting ureteral dilation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not describe the characteristic radiographic appearance of a staghorn calculus.
**Option B:** This option is incorrect because it does not accurately describe the spider leg appearance in IVP.
**Option C:** This option is incorrect because it does not relate to the radiographic appearance of a staghorn calculus.
**Clinical Pearl / High-Yield Fact**
A staghorn calculus is often associated with an increased risk of urinary tract infections (UTIs) due to the stone's ability to harbor bacteria, making prompt diagnosis and treatment essential to prevent complications.
**Correct Answer: C. Staghorn calculus**