Kidney stone formation—Thermodynamic, kinetic, and clinical aspects

The formation of stones in kidney, urinary bladder, or urinary tract, also known as urolithiasis, is a multifactorial disease caused by the accumulation of crystalline deposits in the urine, which poses a great threat to human health. Kidney stones occur as a result of increased supersaturation of the urine causes the dissolved salts and minerals to precipitate, which leads to nucleation, and crystal entities are then accumulated in the renal system. According to stone composition, most urinary stones can be classified as calcium oxalate, struvite, and uric acid stones. Calcium oxalate stones are the most common type of kidney stones and about 80% of urinary stones are composed of calcium oxalate. This review was undertaken to gain an understanding of the mechanisms involved in the formation of kidney stones considering calcium oxalate (CaOx) and struvite crystallization. The classical nucleation and growth theory in aqueous solution and the primary causes that promote crystallization and those that inhibit crystal growth were discussed to understand kidney stone-formation. Several factors may contribute to an increased risk of kidney stone-formation have been discussed in detail.