Kidney stones are hard solid crystal masses made of dissolved minerals and salts that form inside your kidneys when your urine contains more crystal-forming substances than the fluid can dilute. [1, 2, 3]
How They Form
- High concentration: Waste products like calcium, oxalate, or uric acid build up when there is too little liquid in the body.
- Lack of inhibitors: Normal urine lacks enough chemicals that stop crystals from sticking together.
- Movement: Small stones often cause no symptoms until they move out of the kidney into the ureters—the thin tubes connecting the kidneys to the bladder.
Common Symptoms
- Sharp pain in the back, side, or lower abdomen
- Blood in the urine (pink, red, or brown color)
- Nausea and vomiting
- Fever and chills if an infection is present
