In the case of urolithiasis, stones are formed in the kidneys and can gradually increase in size. Basically, kidney stones do not cause any complaints in patients. In cases where the kidney stone moves to the ureter and causes obstruction of the urine output from the kidney (hydronephrosis), severe pain, nausea, vomiting, fever, etc. may occur. The best prevention of urolithiasis is to drink plenty of fluids.