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PubMed2002

Calcium nephrolithiasis: effect of water hardness on urinary electrolytes.

OBJECTIVES: To analyze the impact of water hardness from public water supplies on calcium stone incidence and 24-hour urine chemistries in patients with known calcium urinary stone formation. Patients are frequently concerned that their public water supply may contribute to urinary stone disease. Investigators have documented an inverse relationship between water hardness and calcium lithogenesis. Others have found no such association. METHODS: Patients who form calcium stones (n = 4833) were identified geographically by their zip code. Water hardness information from distinct geographic public water supplies was obtained, and patient 24-hour urine chemistries were evaluated. Drinking water hardness was divided into decile rankings on the basis of the public water supply information obtained from the Environmental Protection Agency. These data were compared with patient questionnaires and 24-hour urine chemistries. The calcium and magnesium levels in the drinking water were analyzed as independent variables. RESULTS: The number of total lifetime stone episodes was similar between patients residing in areas with soft public water and hard public water. Patients consuming the softest water decile formed 3.4 lifetime stones and those who consumed the hardest water developed 3.0 lifetime stones (P = 0.0017). The 24-hour urine calcium, magnesium, and citrate levels increased directly with drinking water hardness, and no significant change was found in urinary oxalate, uric acid, pH, or volume. CONCLUSIONS: The impact of water hardness on urinary stone formation remains unclear, despite a weak correlation between water hardness and urinary calcium, magnesium, and citrate excretion. Tap water, however, can change urinary electrolytes in patients who form calcium stones.

Adolescent↗
PubMed1998

Extracorporeal shock wave lithotripsy for lower pole nephrolithiasis: efficacy and variables that influence treatment outcome.

OBJECTIVES: Extracorporeal shock wave lithotripsy (ESWL) for the treatment of lower caliceal stones (LCS) tends to have a poor success rate, prompting many urologists to advocate alternative treatment modalities. This study attempts to identify variables that may influence the outcome of ESWL treatment for LCS to help in selecting patients that are likely to benefit from the treatment. METHODS: One hundred forty-two patients with isolated LCS treated with the Dornier HM3 lithotriptor were reviewed. The study data include characteristics of patients, stones, urinary tract treated, previous treatment of stones in the same kidney, and details of the ESWL treatment. RESULTS: Eighty patients (56%) were stone free 3 months after ESWL. Multivariate analysis with logistic regression identified six independent and significant variables that influenced treatment outcome: these included number of stones (P = 0.001), previous percutaneous nephrostolithotomy (PNL) treatment (P = 0.001), side of the stone (P = 0.002), presenting stone type (P = 0.004), number of ESWL sessions (P = 0.01), and maximum kilovoltage setting of ESWL at treatment (P = 0.02). Stone size did not influence the treatment outcome in this study. CONCLUSIONS: ESWL provides an acceptable first line treatment for patients with LCS. Patients who fail ESWL and have poor prognostic features (ie, multiple LCS, hard stones requiring high voltage and multiple ESWL sessions, lower caliceal stone formation secondary to ESWL treatment of stones in other locations of the renal unit, or previous treatment with PNL) should be counseled for alternative treatment modalities.

Adolescent↗
PubMed1999

Canine and feline nephrolithiasis. Epidemiology, detection, and management.

Calcium oxalate (39%) and struvite (33%) were the predominant mineral types in canine nephroliths submitted to the Minnesota Urolith Center. Urate salts (12%) and calcium phosphate (2%) occurred less frequently. Provided they are not causing obstruction, struvite nephroliths may be dissolved with medical protocols. Although there are no dissolution protocols for nephroliths containing calcium, risk-benefit ratios should be considered before proceeding with surgery.

Animals↗
PubMed2001

Measurement of nephrolithiasis urinary markers by capillary electrophoresis.

A previously developed method for screening organic acidurias by capillary electrophoresis has been validated for oxalate and citrate measurement in urine. Sample pretreatment is minimum, just acidification and centrifugation. Detection is by direct UV. Validation parameters of the method can be considered adequate. Response is linear for both analytes in standards and samples. The assayed ranges were 200-1,000 mg/l for citrate and 10-200 mg/l for oxalate. Recoveries ranged from 99.4+/-3 to 101.7+/-2.4%, maximum imprecision in oxalate concentration was of 7.6% RSD and limits of detection in samples were 0.67 mg/l for oxalate and 25.9 mg/l for citrate, both lower than the measured values in samples. Identification of increased glyoxylic (oxoacetic acid) and glyceric acids (2,3-dihydroxy propanoic) are also included to facilitate the diagnosis.

Biomarkers↗
PubMed2002

Medical evaluation of nephrolithiasis.

A careful and individualized evaluation of risk factors is a fundamental part of the management of patients with urinary tract stone disease. Identification and correction of important abnormalities provide the basis for designing an efficient and rational treatment program, aiming at an arrest or at least reduction of recurrent stone formation. It is beyond doubt that appropriate therapeutic steps in this regard are of great benefit for the patient. It needs to be emphasized, however, that no success will be obtained unless the patient is willing and able to follow the ensuing dietary recommendations and medical advice.

Calcium Oxalate↗
PubMed2002

Pathophysiology of hypocitraturic nephrolithiasis.

Urinary citrate inhibits calcium stone formation by complexing calcium in a soluble form and by effects on urinary crystals to prevent growth to stones. Low urinary citrate has been recognized for several decades as a contributing factor in some stone forming patients, but recent studies have elucidated the mechanisms and derangements of the renal handling of citrate in various conditions. In addition, oral citrate as an alkalinizing agent can not only increase urinary citrate, but also favorably impact other stone-promoting conditions. This review will focus on the understanding of these concepts.

Age Factors↗
PubMed2002

Hyperuricosuric calcium nephrolithiasis.

Since the findings of Yü and Gutman [1], the hyperuricosuric calcium stone former is a unique clinical entity. While an impressive number of clinical and epidemiologic studies implicate hyperuricosuria in calcium stone formation, the exact physicochemical mechanism by which uric acid affects calcium oxalate crystallization has not been proven. Allopurinol decreases stone recurrences and is the drug of choice for patients with isolated HCN.

Allopurinol↗
PubMed2001

Efficacy and outcome of surgical intervention in patients with nephrolithiasis and chronic renal failure.

AIM: To prospectively evaluate the efficacy and outcome of surgical intervention in patients with renal stones and chronic renal insufficiency. METHODS: The study was carried out from January 1999 till January 2001. Only patients with chronic renal failure without medical renal disease were taken up for study. All patients were subjected to an ultrasound assessment of the kidney, ureter and bladder. In case of obstructed and infected systems a preliminary percutaneous nephrostomy was carried out. After correction of dyselectrolytemia, acid base imbalance and dialysis (if indicated) patients were subjected to surgical intervention (open surgery or percutaneous nephrolithotomy). ESWL was offered for stones persisting after surgery. The stone burden, composition, therapeutic procedures required to render patients stone free were assessed. The outcome of stone removal on renal function was also evaluated by serial renal dynamic scans and creatinine clearance estimations. RESULTS: Out of 90 patients operated for staghorn or calyceal calculi, complete follow up data was available in 70. Pyelo-nephrolithotomy and percutaneous nephrolithotomy was carried out in 63 and 7 patients respectively. Out of 15 patients with residual stones ESWL was successfully performed in 9 cases. Mixed, calcium oxalate monohydrate, calcium oxalate dihydrate, and struvite stones were encountered in 48%, 14%, 17% and 21% respectively. The average pre operative serum creatinine was 4.76 (1.9-16) mg%. The maximum duration of follow up was 9 months. By the 9th post operative month the average fall in serum creatinine values was 1.53 mg/dl (32%) and the average functional improvement by renal dynamic scans stood at 20.665%. 41 patients were saved from further dialysis. CONCLUSION: Patients with mild to moderate renal failure showed maximal improvement in renal function forestalling or reducing the need for dialysis/renal replacement therapy.

Adult↗
PubMed1982

Pathogenesis and clinical course of mixed calcium oxalate and uric acid nephrolithiasis.

By direct measurement, urine from patients who form calcium oxalate stones was supersaturated abnormally with respect to calcium oxalate monohydrate but not supersaturated with respect to undissociated uric acid. Urine from patients who form uric acid stones was supersaturated excessively with undissociated uric acid but not calcium oxalate. Patients who form both calcium oxalate and uric acid stones, however, produce urine that is supersaturated with respect to both solid phases. Low urine pH was the primary factor that increased supersaturation with respect to undissociated uric acid. The formation of both calcium oxalate and uric acid stones appears to be explained by a dual abnormality of urine supersaturation.

Calcium Oxalate↗
PubMed1994

Calcium oxalate nephrolithiasis, a free or fixed particle disease.

The chances of stone formation occurring through a free particle mechanism were calculated using the approach of Finlayson and Reid [1]. For these calculations we used new data on nephron dimensions, supersaturation and crystal growth rates in urine, and also incorporated the size increasing effect of crystal agglomeration. The calculations were performed assuming different levels of oxalate excretion, simulating the diurnal variation and acute hyperoxaluria following a dietary load. In addition urinary flow conditions were varied according to changes in daily urinary volume. It is shown that during the normal transit time of urine through the nephron, particles can obtain a size big enough to be retained in the nephron. This is mainly due to the size-increasing effect of the agglomeration process. The precipitable amount of oxalate present is not limiting for the maximum attainable particle size. However, acute increases in oxalate excretion do pose a risk because supersaturation is reached earlier in the nephron and consequently the crystal particles are allowed more time to increase in size. In conclusion, the present calculations demonstrate that during the normal transit time through the kidney, crystalline particles can be formed which are large enough to be retained because of their size and thus form the nidus of a stone. The highest risk is encountered at the end of those collecting ducts where crystals formed in nephrons with a long loop of Henle meet and agglomerate.

Animals↗