21/03/2026
Kidney stone formation begins deep inside the renal tubules, which are tiny passages in the kidneys that filter blood and produce urine. Normally minerals and salts in the urine stay dissolved as they move through these narrow channels. When the urine becomes too concentrated the minerals can start sticking together. This creates tiny crystal seeds that settle along the tubule walls.
As more minerals pass through the tubules these early crystals attract additional layers and begin to grow. The tubules are very small so even a slight increase in size can cause the crystal to block the flow of fluid. When this happens the stone becomes larger and harder because more material keeps depositing on its surface. Over time a small crystal can turn into a solid stone with sharp edges or a smooth surface depending on its composition.
Once the stone becomes big enough it may break free from the tubule and move into larger parts of the kidney. This movement can irritate the lining of the urinary system and eventually lead to pain if the stone travels toward the ureter. The entire process depends on urine concentration, mineral levels, hydration, and the balance of natural substances that normally prevent stones from forming.
