A 52-year-old woman from Bangalore with a history of recurrent urinary tract infections presents with acute right flank pain and fever (38.5°C). NCCT abdomen shows a 9 mm right ureteric stone at the mid-ureter with moderate hydronephrosis. Urine culture is positive for E. coli. Serum creatinine is 1.8 mg/dL (baseline 1.0 mg/dL). What is the most appropriate immediate next step in management?

Explanation

## Clinical Context This is an **infected obstructed kidney (pyonephrosis)** — a urological emergency. The combination of fever, positive urine culture, elevated creatinine, and obstructing stone with hydronephrosis mandates urgent decompression. ## Infected Obstructed Kidney: Emergency Pathway ```mermaid flowchart TD A[Fever + obstructing stone + hydronephrosis]:::urgent --> B[Infected obstructed kidney]:::urgent B --> C{Sepsis / haemodynamic instability?}:::decision C -->|Yes| D[Resuscitate: IV fluids, vasopressors]:::action C -->|No| E[Stabilize: IV fluids, antibiotics]:::action D --> F[Urgent decompression]:::action E --> F F --> G{Renal function / anatomy?}:::decision G -->|Normal, accessible ureter| H[Urgent ureteroscopy + stent]:::action G -->|Impaired or complex| I[Percutaneous nephrostomy]:::action H --> J[Definitive stone removal at 4-6 weeks]:::action I --> K[Delayed ureteroscopy/ESWL after recovery]:::action ``` ## Key Point: **In infected obstructed kidney, percutaneous nephrostomy is preferred over immediate ureteroscopy if renal function is significantly impaired or anatomy is complex.** This allows rapid decompression and sepsis control before definitive stone removal. ## High-Yield Indications for Percutaneous Nephrostomy: - Fever + obstructing stone + elevated creatinine (this case) - Sepsis with haemodynamic instability - Failed or contraindicated ureteroscopy - Anatomical complexity (e.g., stricture, previous surgery) - Solitary kidney with obstruction ## Clinical Pearl: **The "golden rule" of infected obstructed kidney**: Decompression (drainage) takes priority over stone removal. Antibiotics alone without drainage will fail and risk septic shock. Percutaneous nephrostomy achieves rapid decompression (within hours) and allows the patient to recover renal function before definitive stone extraction 4–6 weeks later. ## Why NOT Immediate Ureteroscopy? Although ureteroscopy can achieve both decompression and stone removal in one procedure, it requires: 1. Intact renal function and stable haemodynamics 2. Experienced endourologist 3. Risk of urosepsis if instrumentation causes bacteraemia In this case, **creatinine is 1.8 mg/dL (elevated from baseline)**, signalling renal compromise. Percutaneous nephrostomy is safer and faster. ## Antibiotic Timing: Start broad-spectrum antibiotics (e.g., piperacillin-tazobactam or fluoroquinolone + aminoglycoside) **immediately** after blood cultures, but do NOT delay percutaneous nephrostomy for antibiotic effect. [cite:AUA Nephrolithiasis Guidelines; Assimos et al., Urology 2016]