Uric acid nephrolithiasis: An update

Uric acid nephrolithiasis appears to increase in prevalence. While a relationship between uric acid stones and low urinary pH has been for long known, additional association with various metabolic conditions and pathophysiological basis has recently been elucidated. Some conditions such as diabetes and metabolic syndrome disease, excessive dietary intake, and increased endogenous uric acid production and/or defect in ammoniagenesis are associated with low urinary pH. In addition, the phenomenon of global warming could result in an increase in areas with greater climate risk for uric acid stone formation. There are three therapeutic steps to be taken for management of uric acid stones: identification of urinary pH profiles, assessment of urinary volume status, and identification of disorders leading to excessive uric acid production. However, the most important factor for uric acid stone formation is acid urinary pH, which is a prerequisite for uric acid precipitation. This article reviews recent insights into the pathophysiology of uric acid stones and their management.

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Diagnosis and management of uric acid nephrolithiasis

Annals of King Edward Medical University ◽

10.21649/akemu.v10i2.1199 ◽

2016 ◽

Vol 10 (2) ◽

Author(s):

Naveed Iqbal ◽

Nawaz Chughtai.

Keyword(s):

Uric Acid ◽

Urinary Calculi ◽

Uric Acid Stone ◽

X Ray ◽

Extracorporeal Shock Wave ◽

Uric Acid Stones ◽

Uric Acid Nephrolithiasis ◽

Stone Dissolution ◽

Prevention Of Recurrence ◽

Percutaneous Nephrolithotripsy

The aim is to provide an account of the diagnosis & management of uric acid stones. Material & methods: A search was made on the topic of uric acid stones with regard to the diagnosis & management of uric acid stones. Results: The incidence of uric acid stones varies between countries and account for 5% to 40% of all urinary calculi. Uric acid stone cannot be seen on x-ray. Intra venous uroghraphy, CT scan or sonoghraphy is required for their diagnosis. This is the only stone that can be reliably dissolved by urinary alkalization with alkali (Bicarbonates, citrate). This medical treatment is highly effective resulting in dissolution of existing stones & prevention of stones. Extracorporeal shock wave lithotripsy and percutaneous nephrolithotripsy can be used successfully for uric acid stones. Open surgery is still performed especially for large complicated staghorn stones. Conclusion: Medical management with urinary alkalization for uric acid stone dissolution and prevention of recurrence is effective.

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A comparison of the metabolic profiles of diabetic and non-diabetic uric acid stone formers

Canadian Urological Association Journal ◽

10.5489/cuaj.820 ◽

2013 ◽

Vol 7 (3-4) ◽

pp. e190-2 ◽

Cited By ~ 3

Author(s):

Alfonso Fernandez ◽

Andrew Fuller ◽

Reem Al-Bareeq ◽

Linda Nott ◽

Hassan Razvi

Keyword(s):

Uric Acid ◽

Dietary Advice ◽

Diabetic Patients ◽

Metabolic Profiles ◽

Uric Acid Stone ◽

Metabolic Evaluation ◽

Urine Ph ◽

Oxalate Excretion ◽

Stone Formers ◽

Uric Acid Stones

Introduction: The aim of this study was to compare the metabolic profiles of diabetic and non-diabetic patients with uric acid stones to understand whether preventive strategies should be tailored to reflect different causative factors.Methods: The results of the metabolic evaluation of patients with uric acid stones identified prospectively from the Metabolic Stone Clinic at St. Joseph’s Hospital, London, Canada were reviewed. Information included patients’ clinical histories, 24 hour urine collections, blood chemistry and stone analysis.Results: Complete data were obtained from 68 patients with uric acid stones. Twenty-two patients had diabetes. There were no statistically significant differences in mean age, body mass index, or history of gout. Among diabetics, pure uric acid stones were identified in 14 patients (63%) and mixed uric acid in 8 (36%). Pure uric acid stones were more common in the diabetic cohort (63% vs. 46%, p = 0.16). Urine pH, serum and urine uric acid levels and 24-hour urine volumes were similar in both groups. The diabetic group had an increased average oxalate excretion (424 μmol/d vs. 324 μmol/d, p = 0.003).Conclusion: The exact etiological basis for the higher oxalate excretion in diabetic uric acid stone formers is unclear. Whether this is a metabolic feature of diabetes, due to dietary indiscretion or the iatrogenic consequence of dietary advice requires further investigation.

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Biochemical and dietary factors of uric acid stone formation

Urolithiasis ◽

10.1007/s00240-017-0965-2 ◽

2017 ◽

Vol 46 (2) ◽

pp. 167-172 ◽

Cited By ~ 6

Author(s):

Alberto Trinchieri ◽

Emanuele Montanari

Keyword(s):

Uric Acid ◽

Stone Formation ◽

Dietary Factors ◽

Uric Acid Stone

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Prevention of uric acid stone formation by sodium bicarbonate in an ileostomy patient —A case report

The Japanese Journal of Surgery ◽

10.1007/bf02471474 ◽

1988 ◽

Vol 18 (4) ◽

pp. 465-468 ◽

Cited By ~ 4

Author(s):

Tsuneo Fukushima ◽

Akira Sugita ◽

Shigeyuki Masuzawa ◽

Yasunobu Yamazaki ◽

Hiroshi Takemura ◽

...

Keyword(s):

Uric Acid ◽

Case Report ◽

Sodium Bicarbonate ◽

Stone Formation ◽

Uric Acid Stone

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V6-06 URINE ACIDITY IS THE MOST IMPORTANT FACTOR IN URIC ACID STONE FORMATION: AN ILLUSTRATION

The Journal of Urology ◽

10.1016/j.juro.2016.02.406 ◽

2016 ◽

Vol 195 (4S) ◽

Author(s):

Steeve Doizi ◽

Kathy Hill ◽

John Poindexter ◽

Margaret Pearle ◽

Khashayar Sakhaee ◽

...

Keyword(s):

Uric Acid ◽

Stone Formation ◽

Uric Acid Stone

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Who makes uric acid stones and why—observations from a renal stones clinic

Journal of Clinical Pathology ◽

10.1136/jclinpath-2012-201373 ◽

2013 ◽

Vol 66 (5) ◽

pp. 426-431 ◽

Cited By ~ 6

Author(s):

Elizabeth M Stansbridge ◽

Damian G Griffin ◽

Valerie Walker

Keyword(s):

Uric Acid ◽

Urine Volume ◽

Renal Stones ◽

Dominant Factor ◽

Uric Acid Stone ◽

Calcium Stones ◽

Oxalate Excretion ◽

Stone Formers ◽

Uric Acid Stones ◽

Patients With Diabetes

AimsExcessively acidic urine is the dominant factor in uric acid stone formation. Recent evidence implicating insulin resistance has revived interest in its causation. We reviewed data on uric acid stone formers attending a general stones clinic to find out whether this supports and adds to current concepts.MethodsA retrospective database study of 1504 stone formers investigated at the Southampton renal stones clinic from 1990 to March 2007. Uric acid stone formers and idiopathic calcium stone formers were compared using non-parametric tests.ResultsFifty-nine patients (3.9%; 43 men) had uric acid stones. In men the commonest associated conditions were diabetes (20%), gout (20%) and an ileostomy (15%); in women, diabetes (33%), urinary infections (27%) and hyperparathyroidism (20%). Most patients with diabetes (85% of men, 75% of women), however, produced calcium stones. Risk factors did not differ significantly between calcium and uric acid stone formers with diabetes, gout or ileostomies. The median urine pH of men with idiopathic calcium stones was 6.20, idiopathic uric acid stones 5.47, diabetes 5.68, gout 6.05, diabetes and gout 5.20 and ileostomy 5.10. Plasma urate was higher with gout and idiopathic uric acid stones. Urate excretion was increased in gout. Oxalate excretion was lower with idiopathic uric acid stones (new finding). Urine volume decreased and oxalate concentration increased with ileostomy.ConclusionsUric acid stones are increased in diabetes, but most patients with diabetes make calcium stones. Different mechanisms may explain low pH with diabetes, gout and idiopathic stones. Low oxalate excretion with idiopathic urate stones needs confirmation.

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