What is Nephrolithiasis?
Nephrolithiasis is the medical term for kidney stones—a condition where crystals precipitate from urine and form solid masses within the urinary tract. 1
Definition and Pathophysiology
Nephrolithiasis develops when the urinary concentration of crystal-forming substances becomes excessively high or when substances that normally inhibit stone formation are present in insufficient amounts. 1 The process involves multiple steps including nucleation, crystal growth, aggregation, and retention within the kidney. 2
Stone Composition
The vast majority of kidney stones consist of specific mineral types:
- Calcium-based stones (calcium oxalate, calcium phosphate, or both) account for approximately 80% of all adult kidney stones 1
- Other stone types include struvite (infection stones), uric acid, and cystine stones 1
Epidemiology and Clinical Significance
The lifetime prevalence differs substantially by sex:
Without treatment, the 5-year recurrence rate after an initial stone episode ranges from 35% to 50%, making this a chronic condition requiring long-term management. 1
Underlying Mechanisms
Stone formation results from an interaction between genetic predisposition and environmental factors. 1 The driving force is urinary supersaturation with stone-forming salts, which occurs when ion concentrations exceed the thermodynamic solubility threshold for that particular salt. 3 Renal cellular dysfunction—whether intrinsic or triggered by external factors—plays a critical role by affecting the excretion of calcium, oxalate, and citrate, as well as the production of crystallization modulators like osteopontin and Tamm-Horsfall protein. 3