From the Guidelines
Yes, anuric patients on dialysis can still form kidney stones, though it's less common than in patients with functioning kidneys. Even with minimal or no urine production, metabolic factors and mineral imbalances that occur in end-stage renal disease can lead to stone formation within the kidney's collecting system. These stones typically develop from calcium oxalate, calcium phosphate, or uric acid deposits. Dialysis patients are particularly susceptible due to altered calcium and phosphate metabolism, secondary hyperparathyroidism, and medication effects. Prevention strategies include:
- Maintaining proper dialysis adequacy
- Controlling serum phosphate levels with phosphate binders like sevelamer or calcium acetate
- Managing secondary hyperparathyroidism with vitamin D analogs or calcimimetics like cinacalcet
- Ensuring appropriate fluid management between dialysis sessions Some patients may require targeted medications based on stone composition, such as allopurinol for uric acid stones. Regular monitoring of serum calcium, phosphate, and parathyroid hormone levels is essential for preventing stone formation in this population, as supported by guidelines from the American College of Physicians 1. Additionally, studies on peritoneal dialysis adequacy suggest that anuric patients may not require higher doses of dialysis to prevent stone formation, and that a peritoneal Kt/Vurea of at least 1.7 per week may be sufficient 1.
From the Research
Formation of Kidney Stones in Anuric Patients on Dialysis
- Anuric patients on dialysis can still form kidney stones, as evidenced by a case report of a 42-year-old man with end-stage renal disease due to ADPKD who developed bilateral renal pelvic stones and nephrocalcinosis while on hemodialysis 2.
- The case report highlights the importance of considering renal colic in anuric patients on dialysis, as they can still experience symptomatic renal tract stones despite their anuric state.
- The study suggests that patients on dialysis are capable of forming symptomatic renal tract stones even if they are anuric, emphasizing the need for awareness and prompt diagnosis in this patient population.
Risk Factors and Stone Formation
- While there is limited direct evidence on the topic, studies on uric acid nephrolithiasis and hyperuricosuric calcium urolithiasis provide insight into the potential risk factors for stone formation in anuric patients on dialysis 3, 4.
- These studies suggest that factors such as hyperuricosuria, hypercalciuria, and hypocitraturia may contribute to the formation of calcium oxalate stones, which could be relevant to anuric patients on dialysis.
- However, more research is needed to fully understand the risk factors and mechanisms of stone formation in this specific patient population.
Dialysis and Stone Formation
- The relationship between dialysis and stone formation is complex, and more research is needed to understand the potential effects of dialysis on stone formation in anuric patients 5, 6.
- Studies on dialysate sodium concentrations and peritoneal solute clearances provide some insight into the management of anuric patients on dialysis, but do not directly address the topic of stone formation.