What is the disposition for an obstructing urinary stone?

Management of Obstructing Urinary Stones

In patients with obstructing urinary stones and suspected infection, urgent decompression of the collecting system via either percutaneous nephrostomy (PCN) or ureteral stenting is strongly recommended, with definitive stone treatment delayed until sepsis is resolved. 1

Initial Assessment and Management

• For patients with obstructing stones without signs of infection, medical management with fluids and pain control can be considered, especially for smaller stones that may pass spontaneously 1
• NSAIDs (diclofenac, ibuprofen, metamizole) are the first-line treatment for renal colic pain management, with opioids as second-line agents 1
• Medical expulsive therapy with alpha-blockers is recommended for patients with stones >5mm in the distal ureter to facilitate stone passage 1, 2

Management Algorithm for Obstructing Stones with Infection/Sepsis

Step 1: Urgent Decompression

• Immediate decompression of the collecting system is required in cases of sepsis and/or anuria with an obstructed kidney 1
• Options include:
  • Retrograde ureteral stenting: First-line approach in most cases, associated with decreased hospital stay and ICU admission rates compared to PCN 1
  • Percutaneous nephrostomy (PCN): Consider when retrograde stenting fails or in specific scenarios 1

Step 2: Antibiotic Management

• Collect urine for culture before and after decompression 1
• Start broad-spectrum antibiotics immediately 1
• Adjust antibiotic regimen based on culture results 1

Step 3: Definitive Stone Management (after resolution of infection)

• For stones ≤20mm: Either shock wave lithotripsy (SWL) or ureteroscopy (URS) 1
• For stones >20mm: Percutaneous nephrolithotomy (PCNL) is first-line therapy 1
• Patients treated initially with PCN are more likely to receive definitive treatment via a percutaneous approach, while those with ureteral stents typically undergo ureteroscopic treatment 1

Specific Considerations for Decompression Method Selection

Retrograde Ureteral Stenting

• Technical success rate around 80% 1
• Benefits:
  • Less invasive than PCN
  • Lower number of subsequent interventions compared to PCN 1
  • Shorter hospital stays and lower ICU admission rates 1
• Limitations:
  • May be associated with higher risk of urosepsis in patients with extrinsic ureteral obstruction 1
  • Higher documented fever rates compared to PCN 1

Percutaneous Nephrostomy (PCN)

• Technical success rate approaches 100% 1
• Preferred in:
  • Patients at high risk for anesthesia 1
  • Cases of pyonephrosis requiring larger tube decompression 1
  • Failed retrograde stenting attempts 1
• Advantages:
  • Shorter dwell time compared to ureteral stents 1
  • Can serve as access for future antegrade stone treatment 1

Percutaneous Antegrade Ureteral Stenting

• Consider when retrograde stenting fails 1
• Caution: Prolonged guidewire and catheter manipulation can increase risk of urosepsis 1
• Technique: Minimize manipulation during initial access and monitor patient closely for signs of worsening sepsis 1

Special Populations

Pregnant Patients

• Ultrasound is the first-line imaging modality, followed by MRI if needed 1
• Hydronephrosis is common in later stages of pregnancy due to uterine compression 1
• If stone disease with infection is suspected, decompression is necessary 1
• Retrograde stenting with minimal or no fluoroscopy is preferred 1

Common Pitfalls and Caveats

• Delaying decompression in obstructing stones with infection can lead to sepsis and death 3
• Do not attempt definitive stone treatment before resolving infection 1
• Avoid SWL as first-line therapy for stones >20mm due to reduced stone-free rates and increased need for multiple treatments 1
• Even nonobstructing stones can cause significant pain and may benefit from removal to improve quality of life 4
• In children, stones ≤3.5mm are more likely to pass spontaneously and may be managed conservatively in clinically stable, non-septic patients 5
• Forniceal rupture due to obstructing stones may appear alarming on imaging but does not necessarily change management approach or outcomes 6