Adder head appearance on intravenous pyelographv is seen in: March 2012
**Core Concept**
The adder head appearance on intravenous pyelography (IVP) refers to a radiological finding where the ureter appears to have multiple branching or a "head" resembling an adder or viper. This is typically due to the presence of a ureteral stone or a ureteral stricture causing obstruction and subsequent dilatation of the ureter.
**Why the Correct Answer is Right**
The adder head appearance is caused by the presence of a ureteral stone or stricture, which leads to ureteral dilatation and tortuosity. As the stone or stricture obstructs the ureter, the surrounding ureteral wall becomes thickened and the lumen becomes narrowed. This results in a characteristic "adder head" appearance on IVP due to the multiple branching or tortuous course of the ureter.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because the adder head appearance is not typically associated with ureteral cancer, which would more likely present with a ureteral mass or obstruction.
* **Option B:** This option is incorrect because the "cut-off" sign on IVP is more characteristic of a ureteral stricture or stone, whereas the adder head appearance is due to ureteral dilatation and tortuosity.
* **Option C:** This option is incorrect because the "cup and handle" sign on IVP is a feature of a ureteral stone or stricture, but it does not resemble the adder head appearance.
**Clinical Pearl / High-Yield Fact**
The adder head appearance on IVP is a high-yield radiological finding that suggests ureteral obstruction, which can be caused by a variety of factors including stones, strictures, and tumors. It is essential to recognize this sign to diagnose and manage ureteral obstruction promptly.
**Correct Answer:** C.