Pathophysiology and Treatment of Uric Acid Stones

2018 ◽  
Author(s):  
Dustin Whitaker ◽  
Ava Saidian ◽  
Jacob Britt ◽  
Carter Boyd ◽  
Kyle Wood ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Metabolic Syndrome ◽  
Uric Acid ◽  
Urine Volume ◽  
Potassium Citrate ◽  
First Line ◽  
Urine Ph ◽  
Stone Composition ◽  
The Metabolic Syndrome ◽  
Uric Acid Stones

Uric acid is the third most common stone composition and comprises 7 to 10% of all kidney stones sent for analysis. These stones are more common with increasing age and in men. Uric acid stone disease is associated with conditions such as the metabolic syndrome and type 2 diabetes mellitus. Uric acid is produced by the enzyme, xanthine oxidase and is the final product of purine metabolism in humans. Three main factors contribute to the formation of uric acid stones: low urine pH (the most important), hyperuricosuria (rare, includes conditions such as myeloproliferative disorders and Lesch-Nyhan syndrome), and low urine volume. Uric acid stones appear radiolucent on plain radiographs and are ultimately diagnosed via stone analysis. These stones may be treated with medical expulsive therapy, dissolution therapy, or surgical intervention depending on the size, location, and clinical presentation. Urine pH manipulation therapy with potassium citrate is the first-line treatment for the prevention of uric acid stones and attempts at dissolution. Allopurinol should not be offered as the first-line therapy for uric acid stones.  This review contains 3 figures, 1 table and 38 references Key Words: ammonium, diabetes mellitus, epidemiology, management, metabolic syndrome, nephrolithiasis, pathophysiology, potassium citrate, uric acid, urine pH

Uric acid stones

2018 ◽  
Author(s):  
Michel Daudon ◽  
Paul Jungers
Keyword(s):  
Type 2 Diabetes ◽  
Uric Acid ◽  
Stone Formation ◽  
Urine Volume ◽  
Potassium Citrate ◽  
Urine Ph ◽  
The Metabolic Syndrome ◽  
Urine Alkalinization ◽  
Recurrent Stone

Uric acid (UA) stones are typically red-orange and often appear as sand/ gravel though they may be large. They are totally radiolucent. They account for about 10% of all kidney stones in most countries, and up to 20% in some populations. It is twice as frequent in males, prevalence increases with age, and it is two to three times higher in patients with type 2 diabetes or with features of the metabolic syndrome. Factors that induce the formation of UA stones are a low urine volume, hyperuricosuria, and, more importantly, a permanently low urine pH (< 5). Indeed, below its pKa of 5.35 at 37°C, UA is in non-dissociated form, whose solubility is at best 100 mg/L, whereas urinary UA excretion normally exceeds 600 mg/day and may exceed 1g/day.Because UA solubility increases up to approximately 500 mg/L at urine pH > 6, urine alkalinization, with a target pH of 6.5–7, is the cornerstone of medical treatment. This most often allows dissolution of existing stones and prevention of recurrent stone formation so that urological intervention is infrequently needed. The preferred agent for alkalinization is potassium citrate (30–60 mEq/day in divided doses), because potassium urate is twice more soluble than sodium urate. However, in patients with poor gastric tolerance to potassium citrate or contraindication to potassium supplements, sodium bicarbonate is an acceptable alternative. Limitation of animal proteins, purine-rich foods (including beer), alcoholic drinks and acidified beverages (sodas) are useful measures, together with large fluid intake (> 2–2.5 L/day). Allopurinol may be indicated in cases of symptomatic hyperuricaemia. Regular observance of alkalinisation, with periodic controls of urine pH by the patient, is needed to prevent the rapid formation of UA stones. Patients affected by UANL, especially if overweight, should be evaluated for type 2 diabetes or glucose intolerance and managed accordingly.

scholarly journals Association of Urine Findings with Metabolic Syndrome Traits in a Population of Patients with Nephrolithiasis

2021 ◽  
Author(s):  
Virginia L Hood ◽  
Kevan M Sternberg ◽  
Desiree de Waal ◽  
John R Asplin ◽  
Carley Mulligan ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Uric Acid ◽  
Calcium Oxalate ◽  
Protein Intake ◽  
Dietary Factors ◽  
Acid Excretion ◽  
Urine Ph ◽  
Stone Composition ◽  
Calcium Oxalate Stones ◽  
Net Acid Excretion

Background and objectives: The odds of nephrolithiasis increase with more metabolic syndrome (met-s) traits. We evaluated associations of metabolic and dietary factors from urine studies and stone composition with met-s traits in a large cohort of stone-forming patients. Design, setting, participants & measurements: Patients >18 years, who were evaluated for stones with 24 h urine collections, July 2009-December 2018, had records reviewed retrospectively. Patient factors, laboratory values and diagnoses were identified within 6 months of urine collection and stone composition within 1 year. Four groups with 0, 1, 2, > 3 met-s traits (hypertension, obesity, dyslipidemia, diabetes) were evaluated. Trends across groups were tested using linear contrasts in analysis of variance and analysis of covariance. Results: 1473 patients met inclusion criteria (835 with stone composition). Met-s groups were 0=684, 1=425, 2=211, 3 and 4 =153. There were no differences among groups for urine volume, calcium or ammonium (NH4) excretion. There was a significant trend (p<0.001) for more met-s traits being associated with decreasing urine pH, increasing age, calculated dietary protein, urine uric acid, oxalate, citrate, titratable acid (TAP), net acid excretion (eNAE) and uric acid supersaturation. The ratio of ammonium to net acid excretion did not differ among the groups. After adjustment for protein intake, the fall in urine pH remained strong, while the upward trend in TAP excretion was attenuated and NH4 decreased. Calcium oxalate stones were most common, but there was a trend for more uric acid (p<0.001) and fewer calcium phosphate (p=0.09) and calcium oxalate stones (p=0.01) with more met-s traits. Conclusions: Stone forming patients with met-s have a defined pattern of metabolic and dietary risk factors that contribute to an increased risk of stone formation including higher acid excretion, largely the result of higher protein intake, and lower urine pH.

scholarly journals Association of Urine Findings with Metabolic Syndrome Traits in a Population of Patients with Nephrolithiasis

Kidney360 ◽  
2021 ◽  
pp. 10.34067/KID.0002292021
Author(s):  
Virginia L. Hood ◽  
Kevan M. Sternberg ◽  
Desiree de Waal ◽  
John R. Asplin ◽  
Carley Mulligan ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Uric Acid ◽  
Calcium Oxalate ◽  
Protein Intake ◽  
Dietary Factors ◽  
Acid Excretion ◽  
Urine Ph ◽  
Stone Composition ◽  
Calcium Oxalate Stones ◽  
Net Acid Excretion

Background: The odds of nephrolithiasis increase with more metabolic syndrome (met-s) traits. We evaluated associations of metabolic and dietary factors from urine studies and stone composition with met-s traits in a large cohort of stone-forming patients. Methods: Patients >18 years, who were evaluated for stones with 24 h urine collections, July 2009-December 2018, had records reviewed retrospectively. Patient factors, laboratory values and diagnoses were identified within 6 months of urine collection and stone composition within 1 year. Four groups with 0, 1, 2, > 3 met-s traits (hypertension, obesity, dyslipidemia, diabetes) were evaluated. Trends across groups were tested using linear contrasts in analysis of variance and analysis of covariance. Results: 1473 patients met inclusion criteria (835 with stone composition). Met-s groups were 0=684, 1=425, 2=211, 3 and 4 =153. There were no differences among groups for urine volume, calcium or ammonium excretion. There was a significant trend (p<0.001) for more met-s traits being associated with decreasing urine pH, increasing age, calculated dietary protein, urine uric acid, oxalate, citrate, titratable acid phosphate, net acid excretion and uric acid supersaturation. The ratio of ammonium to net acid excretion did not differ among the groups. After adjustment for protein intake, the fall in urine pH remained strong, while the upward trend in acid excretion was lost. Calcium oxalate stones were most common, but there was a trend for more uric acid (p<0.001) and fewer calcium phosphate (p=0.09) and calcium oxalate stones (p=0.01) with more met-s traits. Conclusions: Stone forming patients with met-s have a defined pattern of metabolic and dietary risk factors that contribute to an increased risk of stone formation including higher acid excretion, largely the result of greater protein intake, and lower urine pH.

Study Upon the Serum Level of Uric Acid and the Metabolic Syndrome Components

2019 ◽  
Vol 70 (3) ◽  
pp. 1062-1066
Author(s):  
Maria Rada ◽  
Delia Berceanu-Vaduva ◽  
Milan Velimirovici ◽  
Simona Dragan ◽  
Daniel Duda-Seiman ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Uric Acid ◽  
Serum Level ◽  
Abdominal Obesity ◽  
Cardiometabolic Risk ◽  
Serum Levels ◽  
Mean Value ◽  
The Metabolic Syndrome ◽  
Direct Association ◽  
Metabolic Syndrome Components

The serum level of uric acid (UA) appears to be associated with a variety of cardiometabolic risk factors; however, direct association with the metabolic syndrome (MetS) remains controversial. The aim of this study is to investigate the association between serum levels of UA and the components that define MetS, differentiated by gender. 262 patients were enrolled (132 women and 130 men); mean value of the age: 58.7�16 year. Hyperuricemia was considered when the level of serum UA �7mg/dL in men, and � 6mg/dL in women; MetS was defined according to the IDF criteria. The prevalence of MetS in the studied group was 35.11% and the prevalence of hyperuricemia was 16.79%. Men with hyperuricemia had the highest prevalence of abdominal obesity (87.5% vs. 66.32%, p [0.001) and hypertriglyceridemia (65.62% vs. 45.91%, p [ 0.001) versus men with normal level of serum UA. Women with hyperuricemia also had a significantly higher incidence of abdominal obesity (75% vs. 57.51%, p [0.001), hypertriglyceridemia (58.33% vs. 38.33%, p [0.001), decreased HDL (50% vs. 33.33%, p [0.001) and hyperglycemia (66.66% versus 50%, p [0.001) compared to those with normal levels of serum UA. The majority of men with hyperuricemia have more than 4 of the MetS components. Hyperuricemia had a higher prevalence in patients with MetS, it may be considered as a causal factor of MetS. Elevated levels of serum uric acid were significantly more associated with the increasing number of MetS components. Early detection and treatment of hyperuricemia is essential for preventing the metabolic syndrome and its complications.

The Association Between Uric Acid and Hepatic Function Markers With the Metabolic Syndrome in Middle-aged, Overweight, and Obese People

2010 ◽  
Vol 20 (6) ◽  
pp. 312-315
Author(s):  
Angelos A. Evangelopoulos ◽  
Natalia G. Vallianou ◽  
Demosthenes B. Panagiotakos ◽  
Aikaterini T. Georgiou ◽  
Georgios A. Zacharias ◽  
...  
Keyword(s):  
Metabolic Syndrome ◽  
Uric Acid ◽  
Hepatic Function ◽  
Middle Aged ◽  
Obese People ◽  
The Metabolic Syndrome
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