The prevalence of kidney stone disease is increasing, afflicting 7%–11% of the United States population. Multiple systemic conditions, including obesity and diabetes, are also on the rise. Further, the literature has demonstrated a strong association between metabolic syndrome, its components, and kidney stone disease. In this article, we aim to review the associations of metabolic syndrome and nephrolithiasis, discussing the pathophysiology, urinary parameters, and clinical presentations. With this knowledge, urologists will have a more comprehensive understanding of this complex population of metabolic stone formers enabling improved patient management and treatment of stone disease.
Cystinuria is a relatively rare autosomal recessive disorder that manifests early in life and is associated with the development of kidney stones composed of cystine. It is due to mutations in two genes that are involved in the transport of cystine, neutral, and dibasic amino acids in the proximal tubule of the kidney. Patients are at risk for developing chronic kidney disease. Diagnosis is typically established with stone analysis and quantitative urinary cystine excretion. These patients may form extremely large stones requiring percutaneous nephrolithotomy. Stone-prevention strategies include dietary modifications (increased fluid intake and limitation of sodium and animal protein consumption), urine pH manipulation, and thiol-binding agents. These patients should be followed closely, and preemptive stone removal with ureteroscopy should be considered to limit the necessity for more invasive procedures.
This review contains 2 figures and 38 references.
Key Words: a-mercaptopropionyl glycine, amino acid transport, chronic kidney disease, cystinuria, SLC3A1, SLC7A9, thiol-binding agent, urinary pH manipulation
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
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.