From the Guidelines
Kidney stones are primarily caused by an interaction between genetics and environmental exposure, resulting in the crystallization of minerals and salts in the urine. This occurs when the urinary concentration of crystal-forming substances is high or that of substances that inhibit stone formation is low 1. The most common types of kidney stones are calcium oxalate, calcium phosphate, struvite, uric acid, and cystine, with approximately 80% of adults having stones consisting primarily of calcium oxalate, calcium phosphate, or both 1.
Key Factors Contributing to Kidney Stone Formation
- Dehydration, which concentrates the urine and increases the risk of stone formation
- Diet high in sodium and animal protein, which can increase the concentration of lithogenic factors in the urine
- Obesity and certain medical conditions, such as inflammatory bowel disease, which can alter the balance of substances in the urine
- Family history and certain metabolic disorders, which can predispose individuals to kidney stones
- Certain medications, such as diuretics and calcium-based antacids, which can increase the concentration of calcium in the urine
Prevention and Management
Prevention of kidney stones typically involves drinking plenty of water, at least 2 L per day, to dilute the urine and reduce the concentration of lithogenic factors 1. Additionally, reducing sodium and animal protein intake, maintaining a healthy weight, and in some cases, taking medications like thiazide diuretics, allopurinol, or potassium citrate can help prevent the recurrence of kidney stones 1. Understanding the causes of kidney stones and implementing these lifestyle modifications can effectively reduce the risk of recurrence and improve quality of life.
From the Research
Causes of Kidney Stones
- Kidney stones are mineral deposits in the renal calyces and pelvis that are found free or attached to the renal papillae, containing crystalline and organic components 2
- They are formed when the urine becomes supersaturated with respect to a mineral, with calcium oxalate being the main constituent of most stones 2
- Stone formation is highly prevalent, with rates of up to 14.8% and increasing, and a recurrence rate of up to 50% within the first 5 years of the initial stone episode 2
Risk Factors for Kidney Stones
- Obesity, diabetes, hypertension, and metabolic syndrome are considered risk factors for stone formation, which can lead to hypertension, chronic kidney disease, and end-stage renal disease 2
- The formation of stones in the urinary tract stems from a wide range of underlying disorders, making it imperative for clinicians to look for the underlying causes for nephrolithiasis 3
Pathophysiology of Kidney Stones
- The understanding of polygenetic causes of kidney stones is still largely elusive, with advances in genetics, pathophysiology, diagnostic imaging, medical treatment, medical prevention, and surgical intervention of nephrolithiasis 3
- Manipulation of inhibitors and epithelial factors is important and needs further investigation to understand the pathophysiology of kidney stones 3
Prevention and Treatment of Kidney Stones
- Prevention of recurrence requires behavioral and nutritional interventions, as well as pharmacological treatments that are specific for the type of stone 2
- Thiazide diuretic agents, such as hydrochlorothiazide, are widely used for prevention of the recurrence of kidney stones, but data regarding the efficacy of such agents as compared with placebo are limited 4, 5, 6
- Low-dose hydrochlorothiazide was often used for prevention of calcium-containing kidney stones despite the fact that there is no evidence that it is effective in this setting 4
- A double-blind trial found that the incidence of recurrence did not appear to differ substantially among patients receiving hydrochlorothiazide once daily at a dose of 12.5 mg, 25 mg, or 50 mg or placebo once daily 6