Treatment of Infected Kidney Stones
If you encounter an infected kidney stone with obstruction, immediately establish drainage via nephrostomy tube or ureteral stent, start broad-spectrum antibiotics, and abort any stone removal procedure until the infection clears—this is a urological emergency that can rapidly progress to sepsis and death. 1
Emergency Recognition and Initial Management
Identifying the Emergency
An infected obstructed kidney stone presents as a urological emergency requiring immediate intervention. Key clinical indicators include:
This condition can progress to sepsis and death if not managed urgently. 1
Immediate Drainage (First Priority)
Urgent decompression of the collecting system must be performed before any attempt at stone removal. 1 You have two options:
The choice between these depends on local expertise and patient anatomy, but drainage must occur immediately—do not delay for imaging or further workup if clinical suspicion is high. 1
Critical Intraoperative Decision
If purulent urine is encountered during any endoscopic stone procedure, immediately abort the procedure, establish drainage (stent or nephrostomy), obtain urine culture, and continue broad-spectrum antibiotics. 2, 1 Attempting to continue with stone removal in the presence of purulent urine significantly increases sepsis risk and mortality. 2
Antibiotic Therapy
Empirical Coverage
Start broad-spectrum antibiotics immediately upon suspicion of infected obstructed stone, covering gram-negative enterobacteria. 1 Recommended empirical options include:
Tailor antibiotic selection to your institutional antibiogram and the patient's prior culture results. 2 Administer antibiotics within 60 minutes of any planned procedure. 2
Duration and Adjustment
Continue antibiotics until infection resolves completely before attempting definitive stone treatment. 1 Adjust therapy based on culture results from the purulent urine or stone fragments. 2
Definitive Stone Treatment (After Infection Resolution)
Complete Stone Removal is Essential
Complete removal of infected stones or infected stone fragments is mandatory to prevent recurrent UTI, continued stone growth, and progressive renal damage. 2, 1 This is particularly critical because bacteria reside within infection stones (typically struvite/carbonate apatite), making the stone itself a persistent source of infection that cannot be sterilized with antibiotics alone. 2
Treatment Modalities
Once infection has completely resolved, definitive stone removal options include:
For large or staghorn calculi:
- Percutaneous nephrolithotomy (PCNL) as first-line therapy 2, 1
- Combination PCNL with extracorporeal shock wave lithotripsy (ESWL) for complex stones 2, 1
For smaller stones:
PCNL remains the standard for large renal stones, with mini-PCNL (12-22F) offering similar stone-free rates with reduced blood loss and shorter hospital stays compared to standard PCNL. 2
Contraindications to Definitive Treatment
Do not proceed with stone removal if:
- Untreated UTI is present 2
- Patient is on anticoagulants without appropriate management 2
- Pregnancy (for ESWL and PCNL) 2
Post-Treatment Management
Stone Analysis
Send all stone material for compositional analysis to guide metabolic evaluation and prevent recurrence. 2 This is particularly important for infection stones to confirm struvite/carbonate apatite composition. 2
Long-term Antibiotic Considerations
For patients with confirmed infection stones, long-term antibiotic therapy may be considered to prevent recurrence, though this remains somewhat controversial. 3 The primary goal is complete stone removal rather than chronic suppressive antibiotics. 2, 1
Follow-up
Do not treat asymptomatic bacteriuria after successful stone treatment. 1 However, monitor closely for recurrent UTI with urease-producing organisms, as residual fragments can serve as a nidus for stone regrowth and infection. 2
Common Pitfalls to Avoid
Never attempt stone removal in the presence of active infection—this dramatically increases sepsis risk and mortality. 2, 1 The temptation to "finish the case" when purulent urine is encountered must be resisted. 2
Do not assume a negative preoperative urine culture eliminates infection risk—purulent urine can still be encountered intraoperatively, particularly with obstructed systems. 3
Incomplete stone removal leads to recurrent infection—residual fragments of infection stones will continue to harbor bacteria and serve as a nidus for stone regrowth. 2 Aim for complete stone clearance, not just symptomatic relief. 2, 1