A 20 years old female presented to emergency with high grade swinging fever, abdominal tenderness and flank mass. On CT there was collection around kidney. Antibiotics were staed but patient condition didn’t improve after 48 hours. What is the next best treatment option?

**Core Concept**
The patient is presenting with signs and symptoms of pyelonephritis, a type of kidney infection, which has progressed to a perinephric abscess, a collection of pus surrounding the kidney. This condition requires prompt and effective treatment to prevent further complications.

**Why the Correct Answer is Right**
The patient's condition is refractory to antibiotics, indicating a need for drainage of the abscess. A percutaneous drainage is the preferred method, as it is less invasive and has a lower risk of complications compared to open surgery. This procedure involves inserting a catheter into the abscess under imaging guidance, allowing for the drainage of pus and antibiotics to be administered directly into the abscess.

**Why Each Wrong Option is Incorrect**
**Option A:** Surgical exploration is typically reserved for cases where percutaneous drainage is not feasible or has failed, and is associated with higher risks and complications.
**Option B:** Re-evaluation of the antibiotic regimen may be necessary, but in this case, the patient's condition has not improved despite initial antibiotic treatment, suggesting an abscess that requires drainage.
**Option C:** This option is not a viable treatment option for a perinephric abscess.

**Clinical Pearl / High-Yield Fact**
Percutaneous drainage is a safe and effective treatment option for perinephric abscesses, with high success rates and low complication rates.

**Correct Answer:** C.

✓ Correct Answer: A. Percutaneous drainage under CT guidance