A 10-mm calculus in the right lower ureter associated with proximal hydroureteronephrosis is best treated with –
**Core Concept**
The management of ureteric calculi depends on the location, size, and associated complications. In cases of ureteral obstruction, the goal is to relieve the obstruction and prevent further complications such as renal impairment or infection.
**Why the Correct Answer is Right**
A 10-mm calculus in the right lower ureter associated with proximal hydroureteronephrosis requires intervention to prevent permanent kidney damage. **Percutaneous nephrolithotomy (PCNL)** is the preferred treatment for large ureteric stones (> 10 mm) with associated obstruction, as it allows for complete clearance of the stone and relief of the obstruction. This minimizes the risk of complications such as recurrent stone formation, renal scarring, or chronic kidney disease.
**Why Each Wrong Option is Incorrect**
* **Option A:** **Ureteroscopic lithotripsy** is a suitable option for smaller stones (< 10 mm) or those that are more distal in the ureter. However, for a 10-mm calculus with associated obstruction, PCNL is generally preferred due to its higher success rate and reduced risk of complications. * **Option B:** **Shockwave lithotripsy (SWL)** is often used for smaller stones (< 10 mm) and is less effective for larger stones or those with significant obstruction. SWL may not be the best option for a 10-mm calculus with associated hydroureteronephrosis. * **Option D:** **Observation** is not a suitable option for a 10-mm calculus with associated obstruction, as it increases the risk of complications such as recurrent stone formation, renal scarring, or chronic kidney disease. **Clinical Pearl / High-Yield Fact** When managing ureteric calculi, it's essential to consider the location and size of the stone, as well as the presence of associated complications such as obstruction or infection. A thorough understanding of the anatomy and physiology of the urinary tract is crucial in determining the most appropriate treatment approach. **Correct Answer: C. PCNL**