A 42-year-old woman from Delhi presents with acute left flank pain, fever (38.5°C), and pyuria. CT abdomen reveals a 12 mm stone in the left proximal ureter with moderate hydronephrosis and perinephric stranding. WBC is 14,000/μL and creatinine is 1.8 mg/dL (baseline 0.9 mg/dL). What is the most appropriate immediate next step?

Explanation

## Clinical Diagnosis: Obstructed Infected System (Pyonephrosis) This patient has a triad of obstruction, infection, and renal dysfunction — a urological emergency. ## Diagnostic Features | Feature | Finding | Significance | |---------|---------|---------------| | Stone size | 12 mm | Unlikely to pass spontaneously | | Fever | 38.5°C | Infection present | | Pyuria | Present | Infected urine | | Hydronephrosis | Moderate | Obstruction confirmed | | Perinephric stranding | Present | Inflammation/early sepsis | | Renal function | Creatinine 1.8 (↑ from 0.9) | Acute kidney injury from obstruction | | WBC | 14,000/μL | Systemic inflammation | ## Management Algorithm for Obstructed Infected System ```mermaid flowchart TD A[Obstructed infected system diagnosed]:::urgent --> B[Sepsis risk assessment]:::decision B -->|Fever + obstruction + AKI| C[EMERGENCY: Urgent decompression]:::urgent C --> D{Hemodynamically stable?}:::decision D -->|Yes| E[Percutaneous nephrostomy]:::action D -->|No| F[Percutaneous nephrostomy + ICU support]:::action E --> G[Antibiotics: broad-spectrum IV]:::action F --> G G --> H[Renal function recovery: 4-6 weeks]:::action H --> I[Definitive stone management: URS or PCNL]:::action I --> J[Remove nephrostomy tube]:::action ``` **Key Point:** Decompression MUST precede definitive stone removal in infected obstructed systems. Attempting stone extraction in the presence of active infection risks urosepsis and mortality. ## Why Percutaneous Nephrostomy? **High-Yield:** PCN is the safest immediate decompression method because: 1. Bypasses the infected obstructed system 2. Allows infected urine drainage and pressure relief 3. Can be performed under local anesthesia 4. Permits antibiotic therapy to work without systemic toxicity 5. Allows renal function recovery before definitive intervention **Clinical Pearl:** The "septic obstructed kidney" is a surgical emergency. Mortality increases dramatically if decompression is delayed >12 hours in septic patients. Urosepsis can progress to septic shock and multi-organ failure. ## Sequence of Management 1. **Immediate (0–2 hours):** PCN placement + broad-spectrum IV antibiotics (e.g., ceftriaxone + gentamicin ± metronidazole) 2. **Days 1–7:** Antibiotics, fluid resuscitation, monitor renal function 3. **Weeks 4–6:** Renal function stabilization, repeat imaging 4. **Definitive (after 4–6 weeks):** Ureteroscopy with laser lithotripsy or PCNL depending on stone burden 5. **Final:** PCN removal after successful stone clearance **Mnemonic:** **STOP** — **S**eptic obstructed kidney needs **T**ubes (PCN), **O**pen drainage, **P**ostpone definitive stone removal. [cite:Harrison 21e Ch 283; Campbell-Walsh Urology 12e Ch 47]