What are the implications of an infected renal (kidney) stone?

From the Guidelines

Infected renal stones require immediate decompression, preferably by surgical intervention, to prevent serious complications such as urosepsis and renal damage. The management of infected renal stones involves a multidisciplinary approach, including urologists, radiologists, and infectious disease specialists. For initial management, empiric antibiotic therapy should be started immediately with options including fluoroquinolones (ciprofloxacin 500mg twice daily), third-generation cephalosporins (ceftriaxone 1-2g daily), or aminoglycosides (gentamicin 5mg/kg daily), adjusted based on culture results 1.

Key Considerations

• Patients with obstructing and infected stones should be managed promptly to prevent clinical harm and progression 1.
• Definitive treatment typically requires stone removal via procedures such as percutaneous nephrolithotomy, ureteroscopy, or extracorporeal shock wave lithotripsy, depending on stone size and location 1.
• Patients need adequate hydration, pain management with NSAIDs or opioids as needed, and close monitoring for signs of sepsis.
• Following resolution, stone analysis should guide preventive measures including increased fluid intake (2-3 liters daily), dietary modifications, and possibly medications like thiazide diuretics, potassium citrate, or allopurinol based on stone composition.

Surgical Intervention

• Percutaneous nephrolithotomy (PCNL) is a viable option for patients with large stones or those who have failed other treatments 1.
• Ureteroscopy and extracorporeal shock wave lithotripsy (ESWL) are also effective treatments for smaller stones 1.
• The choice of surgical intervention depends on the size, location, and composition of the stone, as well as the patient's overall health and medical history.

Prevention and Follow-up

• Regular follow-up imaging and urine cultures are essential to ensure complete resolution and prevent recurrence.
• Patients should be educated on the importance of increased fluid intake, dietary modifications, and medication adherence to prevent future stone formation.
• Close monitoring for signs of sepsis and prompt intervention are crucial in preventing serious complications and improving patient outcomes 1.

From the Research

Definition and Treatment of Infected Renal Stones

• Infected kidney stones refer to stones that form because of urinary tract infections with urease-producing bacteria, secondarily infected stones of any composition, or stones obstructing the urinary tract leading to pyelonephritis 2.
• The mainstay of treatment of infection stones is complete stone removal 2.
• Obstructive pyelonephritis is a urologic emergency as it can result in sepsis and even death 2.

Antibiotic Treatment and Prophylaxis

• Ciprofloxacin has been shown to be effective in treating renal cyst infections, which are a serious complication of polycystic kidney disease 3.
• Antibiotic prophylaxis strategies for stone surgery show different degrees of effectiveness depending on both the approach and the patient's condition 4.
• Routine antibiotic prophylaxis might not be necessary for all patients with sterile urine undergoing ureterorenoscopy and lithotripsy, but it is beneficial for those patients with positive preoperative urine cultures 4.

Management of Urinary Tract Infections Associated with Nephrolithiasis

• Infection with uropathogens that produce urease can lead to the development of stones (infection stones), which serve as a continued source of recurrent infection and can lead to chronic kidney disease 5.
• Recognizing obstruction and initiating prompt drainage of the collecting system is important in the successful management of nephrolithiasis complicated by UTI 5.
• Patients with nephrolithiasis complicated by UTI are often at high risk of infection with an antimicrobial-resistant pathogen, so careful consideration of antimicrobial therapy is required 5.

Emergency Department Management

• Current guidelines recommend antibiotic therapy for infected obstructive stones and stone removal in a timely fashion, but there is no clear recommendation for prophylactic antibiotic use for bacteriuria or pyuria in the setting of obstructive ureteral stones 6.
• A high rate of infectious complication did not occur in the followed up patient group, suggesting that antibiotics may not always be necessary in the emergency department setting 6.