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The association of nephrolithiasis and autosomal dominant polycystic kidney disease
V E Torres1, S B Erickson, L H Smith
1Department of Diagnostic Radiology, Mayo Clinic, Rochester, MN 55905.
Insights
Nephrolithiasis (kidney stones) is common in autosomal dominant polycystic kidney disease (ADPKD). Uric acid and calcium oxalate stones are frequent, linked to hypocitraturia and lower urine pH in ADPKD patients.
Area of Science:
- Nephrology
- Urology
- Genetics
Background:
- Nephrolithiasis is a frequent complication in autosomal dominant polycystic kidney disease (ADPKD).
- The specific factors contributing to kidney stone formation in ADPKD patients require detailed investigation.
Purpose of the Study:
- To investigate the characteristics and potential causes of nephrolithiasis in patients with ADPKD.
- To analyze stone composition, metabolic abnormalities, and urine parameters in ADPKD patients with kidney stones.
Main Methods:
- Retrospective analysis of 751 ADPKD patients, identifying 151 with nephrolithiasis.
- Stone analysis in 30 patients; excretory urograms reviewed in 79 patients.
- Metabolic evaluation (urine pH, hypocitraturia, hyperuricosuria, hyperoxaluria, hypercalciuria) in 91 patients with preserved renal function.
Main Results:
- Uric acid (56.6%) and calcium oxalate (46.6%) were the most common stone compositions.
- Hypocitraturia was the most frequent metabolic abnormality (10 of 15 patients).
- ADPKD patients exhibited significantly lower urine pH (5.66) compared to controls (5.92).
Conclusions:
- Both metabolic factors (hypocitraturia, low urine pH) and mechanical factors contribute to frequent nephrolithiasis in ADPKD.
- Findings suggest impaired ammonia excretion in ADPKD may influence urine pH and stone formation.
- Further research into metabolic derangements is warranted for managing kidney stones in ADPKD.
Abstract:
Despite the frequency and morbidity of nephrolithiasis in autosomal dominant polycystic kidney disease (ADPKD), this association has not been subject to a detailed study. One hundred fifty-one of 751 ADPKD patients seen at the Mayo Clinic between 1976 and 1986 had nephrolithiasis. Seventy-four had passed calculi or had stones surgically removed. Stone analysis was available in 30 patients: uric acid, calcium oxalate, calcium phosphate, and struvite were present in 56.6%, 46.6%, 20%, and 10%, respectively. Calculi were observed in 71 of 79 patients with excretory urograms available for review. Faintly opaque and bull's eye stones, probably containing uric acid, were present in 12.7% and 14.1% of these patients, respectively. Precaliceal tubular ectasia was observed in 15.5%. Ninety-seven patients had preserved renal function (serum creatinine less than 1.5 mg/dL) at the initial evaluation. Six were excluded because they had other known causes of stone disease. The most common metabolic abnormality in the remaining 91 patients was hypocitric aciduria (ten of 15 patients with measurements). The urine pH in the first voided morning specimens (5.66 +/- 0.05) was significantly lower than that of an unselected control population (5.92 +/- 0.03, P less than 0.001). Hyperuricosuria, hyperoxaluria, and hypercalciuria were observed in six of 32 (18.8%), six of 31 (19.4%), and three of 39 (9.7%) patients with preserved renal function. The composition of the stones, the frequency of hypocitric aciduria, and the low urine pH (possibly related to the defect in excretion of ammonia described in ADPKD), suggest that metabolic, along with mechanical, factors are responsible for the frequent occurrence of nephrolithiasis in this disease.