Should antibiotics be administered routinely to inpatients with kidney stones?

Antibiotics for Inpatient Kidney Stone Management

Routine antibiotic prophylaxis should not be administered to all inpatients with kidney stones unless there are specific indications such as active infection, purulent urine, or high risk for infection. 1

Indications for Antibiotics in Kidney Stone Patients

Antibiotics ARE Indicated When:

• Purulent urine is encountered during endoscopic intervention (abort procedure, establish drainage, continue antibiotics, obtain culture) 1
• Active urinary tract infection (fever, leukocytosis, positive urine culture)
• Infected kidney stones (struvite/infection stones)
• Obstructed collecting system with signs of infection requiring urgent decompression via percutaneous nephrostomy or ureteral stenting 2
• Perioperative prophylaxis for stone removal procedures:
  • Ureteroscopic stone removal
  • Percutaneous nephrolithotomy (PCNL)
  • Open and laparoscopic/robotic stone surgery 1

Antibiotics are NOT Routinely Indicated:

• Uncomplicated kidney stones without signs of infection
• After shock wave lithotripsy (SWL) without infection 1
• Prolonged postoperative antibiotic therapy after uncomplicated ureteroscopy 3

Evidence-Based Antibiotic Recommendations

For Perioperative Prophylaxis:

• Single dose of antibiotic covering gram-positive and gram-negative uropathogens administered within 60 minutes of procedure 1
• For high-risk patients (immunocompromised, recurrent UTIs, uncontrolled diabetes, history of infected stones):
  • Ciprofloxacin or trimethoprim-sulfamethoxazole 1
  • IV antibiotics for complex procedures under general anesthesia 1

For Active Infection with Kidney Stones:

1. Obtain urine culture before starting antibiotics when possible
2. Establish drainage (stent or nephrostomy) in obstructed systems 2
3. Empiric antibiotic options (adjust based on culture results):
   • Meropenem 1g q6h by extended infusion
   • Imipenem/cilastatin 500mg q6h by extended infusion
   • Ceftazidime/avibactam 2.5g q8h for suspected MDR pathogens 1

For Infected Stones (Struvite):

• Complete surgical stone removal combined with targeted antibiotic therapy 4
• Duration of antibiotics remains controversial:
  • Neither 2-week nor 12-week regimens showed superiority in preventing stone recurrence or positive cultures after PCNL 4

Special Considerations

Antibiotic Duration:

• Perioperative prophylaxis: Single dose or until drainage catheters removed 1
• Active infection: Continue until clinical resolution and source control achieved
• Post-ureteroscopy: Peri-stent removal prophylaxis appears sufficient (2% UTI risk) rather than prolonged courses 3

Antibiotic Selection:

• Base on local resistance patterns and prior cultures
• Avoid nephrotoxic antibiotics in patients with renal impairment
• Consider dose adjustment based on renal function 1

Common Pitfalls to Avoid

1. Treating asymptomatic bacteriuria in patients with indwelling urinary devices 1
2. Prolonged antibiotic courses without clear indication
3. Failing to obtain cultures before starting antibiotics
4. Not establishing drainage in infected obstructed systems
5. Misattributing urinary symptoms to infection when they may be due to the stone itself 5

By following these evidence-based guidelines, clinicians can optimize antibiotic use in patients with kidney stones, reducing unnecessary antibiotic exposure while ensuring appropriate treatment when indicated.