**Core Concept**
Bilateral impacted ureteric stones with hydronephrosis can lead to acute kidney injury (AKI) and sepsis due to urinary obstruction and infection. The immediate goal is to relieve the obstruction and manage the infection.

**Why the Correct Answer is Right**
The correct treatment involves relieving the obstruction by using a ureteric stent or percutaneous nephrostomy tube to restore urine flow, thereby reducing the risk of further kidney damage. This is essential in the setting of bilateral hydronephrosis and AKI. Additionally, antibiotics should be initiated to manage the urinary tract infection.

**Why Each Wrong Option is Incorrect**

* **Option A:** This may be part of the treatment but is not the immediate step. Stenting or nephrostomy tube placement is more urgent than starting antibiotics.
* **Option B:** This is incorrect as the primary issue is bilateral obstruction and infection, not just a unilateral issue.
* **Option C:** This is not the immediate treatment as it involves a more invasive procedure and is not the first line of management.

**Clinical Pearl / High-Yield Fact**
In cases of bilateral ureteric obstruction, early intervention with stenting or nephrostomy tube placement is crucial to prevent further kidney damage and progression to sepsis.

**Correct Answer:** C. Placing a percutaneous nephrostomy tube to relieve the obstruction and manage the infection.