What is the management approach for a patient with a renal stone and hydronephrosis?

Management of Renal Stones with Hydronephrosis

For patients with renal stones and hydronephrosis, the initial management should be decompression of the collecting system through either retrograde ureteral stenting or percutaneous nephrostomy (PCN), followed by definitive stone removal based on stone characteristics and patient factors. 1

Initial Assessment and Imaging

• Non-contrast CT scan is the gold standard for diagnosis of renal stones and assessment of hydronephrosis severity 1
• Ultrasound can be used as an initial screening tool with moderate sensitivity (52-57% for renal stones) but has high utility in detecting hydronephrosis 1, 2
• The degree of hydronephrosis correlates with likelihood of spontaneous passage failure and need for intervention 3
  • Absent/mild hydronephrosis: 15-20% intervention rate
  • Moderate hydronephrosis: 28% intervention rate
  • Severe hydronephrosis: 43% intervention rate

Urgent Decompression for Infected Hydronephrosis

• Infected hydronephrosis with obstruction is a urological emergency requiring immediate decompression 4
• Two primary options for urgent decompression:

1. Retrograde Ureteral Stenting

• Advantages:
  • Decreased hospital stay and ICU admission rates compared to PCN 1
  • Lower number of subsequent interventions 1
  • Can be performed during the same session as definitive ureteroscopic treatment 1
• Disadvantages:
  • May have higher risk of urosepsis with extrinsic ureteral obstruction 1
  • May require general anesthesia 1

2. Percutaneous Nephrostomy (PCN)

• Advantages:
  • Higher technical success rate (100% vs 80% for retrograde stenting) 1
  • Preferred for patients at high risk for anesthesia 1
  • Better option for pyonephrosis requiring larger tube decompression 1
• Disadvantages:
  • Higher number of subsequent interventions 1
  • Longer hospital stays (10.09 ± 3.43 days vs 8.18 ± 2.72 days for immediate nephrolithotomy) 1

Definitive Stone Management

After initial decompression in emergency cases or as primary treatment for non-emergent cases:

For Stones <10 mm:

• Medical expulsive therapy (MET) with close monitoring may be appropriate if:
  • Pain is well-controlled
  • No evidence of sepsis
  • Adequate renal function 1
• Patients should be followed with periodic imaging to monitor stone position and hydronephrosis 1

For Stones >10 mm:

• Surgical intervention is typically required 1
• Two primary options:

1. Extracorporeal Shock Wave Lithotripsy (SWL)

• Success rates not significantly affected by presence or degree of hydronephrosis for proximal ureteral stones 5
• Lower stone-free rates but fewer complications compared to ureteroscopy 1

2. Ureteroscopy (URS)

• Higher stone-free rates in a single procedure compared to SWL 1
• Higher complication rates:
  • Ureteral injury: 3-6%
  • Stricture: 1-4%
  • Sepsis: 2-4% 1

3. Percutaneous Nephrolithotomy (PCNL)

• Reserved for complex stone burdens or when other approaches fail 6
• Can be performed after initial PCN placement using the same access tract 1
• Higher risk of systemic inflammatory response syndrome with multiple tracts, larger stones, and significant hydronephrosis 1

Special Considerations

• Infected hydronephrosis: Requires immediate decompression before definitive treatment 4
• Severe hydronephrosis: Associated with significantly higher rates of intervention failure (43%) and warrants prompt definitive management 3
• Pregnancy: Ultrasound-guided approaches preferred to minimize radiation; retrograde stenting often performed without fluoroscopy 1

Follow-up

• Patients with mild hydronephrosis and small stones can be monitored with serial ultrasound 2
• Lack of hydronephrosis on follow-up imaging is a good indicator of successful stone passage 3, 2
• Persistent or worsening hydronephrosis requires reassessment and likely intervention 1