Kidney Stones in CKD Associated with Ileal Conduit or Chronic Diarrhea
Most Common Type of Kidney Stone in CKD with Ileal Conduit/Chronic Diarrhea
Uric acid stones are the most common type of kidney stone found in patients with CKD associated with ileal conduit or chronic diarrhea. 1
Pathophysiology of Uric Acid Stone Formation in These Patients
- Patients with ileal conduit or chronic diarrhea experience chronic volume contraction due to loss of water and salt in diarrheal stool, leading to decreased urine volumes 1
- Loss of bicarbonate in ileostomy effluent or through chronic diarrhea leads to formation of an acidic urine (low pH) 1
- Low urinary pH (below 5.5) is the most important risk factor for uric acid crystallization and stone formation, rather than increased urinary uric acid excretion 2
- The combination of low urine volume and acidic urine significantly decreases the solubility of uric acid, causing crystallization and stone formation 1
Other Stone Types in These Patients
- While uric acid stones are most common in this population, calcium oxalate stones may also occur, particularly in patients with small bowel resection but intact colon 1
- In patients with small bowel resection and intact colon, hyperoxaluria can develop due to:
Sodium Bicarbonate Use in CKD
Sodium bicarbonate is used in CKD primarily to treat metabolic acidosis. 3
Rationale for Sodium Bicarbonate in CKD
- Metabolic acidosis is a common complication in CKD that requires treatment 3
- Metabolic acidosis in CKD patients with ileal conduit or chronic diarrhea is particularly pronounced due to bicarbonate loss 1
- Treatment with alkalinizing agents like sodium bicarbonate raises urine pH to about 6.5, which increases the solubility of uric acid and prevents crystallization 1
Additional Benefits of Treating Acidosis in CKD
- Prevents further kidney damage from chronic acidosis 3
- Helps maintain bone health by preventing bone mineral dissolution 3
- May slow progression of CKD 3
GFR Level When Uremic Symptoms Typically Begin
Uremic symptoms typically begin to manifest when GFR falls to approximately 15 mL/min/1.73m². 4, 5
Progression of Symptoms Based on GFR Levels
- At GFR 30-60 mL/min/1.73m²: Usually minimal symptoms, though early metabolic abnormalities may begin 4
- At GFR 15-30 mL/min/1.73m²: Increasing metabolic abnormalities, but often still limited symptoms 4
- At GFR <15 mL/min/1.73m²: Full manifestation of uremic syndrome including:
Major Advantage of Peritoneal Dialysis over Hemodialysis in ESRD
Continuous removal of fluid is a major advantage of peritoneal dialysis over hemodialysis in ESRD. 6
Benefits of Continuous Fluid Removal in Peritoneal Dialysis
- Provides more stable fluid balance throughout the day 6
- Reduces cardiovascular stress by avoiding rapid fluid shifts seen in hemodialysis 6
- Better preserves residual renal function 6
- May provide better control of blood pressure 6
Other Advantages of Peritoneal Dialysis
- Greater patient autonomy and flexibility in schedule 6
- Can be performed at home without complex equipment 6
- Fewer dietary restrictions in some cases 6
- No need for vascular access and associated complications 6
Disadvantages of Peritoneal Dialysis
- Risk of peritonitis 6
- Requires dedicated space for supplies and equipment at home 6
- May have less efficient clearance of certain molecules compared to hemodialysis 6
Prevention of Kidney Stones in CKD with Ileal Conduit/Chronic Diarrhea
- Increase fluid intake to achieve urine volume above 2 liters daily 2, 1
- Use alkalinizing agents (potassium citrate or sodium bicarbonate) to maintain urine pH between 6.2 and 6.8 2
- Reduce dietary purine intake to decrease urinary uric acid excretion 2
- For patients with small bowel resection and intact colon: