Kidney stones can be asymptomatic, with back pain and hematuria being common symptoms. Later on, hydronephrosis may also occur. If kidney stones lead to obstruction and infection, the stones obstruct the urine drainage, which can easily cause bacterial infection and fever symptoms. In severe cases, it can lead to sepsis, which is life-threatening. 1. Back pain: If the kidney stone is confined to the renal pelvis, it mainly manifests itself in pain, soreness and discomfort in the lower back. If the stone slips into the ureter and causes impaction, it will cause severe colic. Colic often occurs suddenly, with a cutting pain in one side of the lower back. It may radiate to the lower abdomen, vulva and inner thighs. The duration varies. After the pain, there is mostly hematuria, and some patients can be found to discharge stones. 2.Hematuria: After renal colic, there is mostly hematuria, of which only some can be found red with the naked eye, and most are microscopic hematuria. 3. Asymptomatic: A few stones in the renal pelvis are large, inactive, and without obvious obstructive infection, they can be asymptomatic for a long time. Many patients find kidney stones by chance during physical examination, usually without any symptoms. 4, hydronephrosis: stones slowly grow up and block the renal pelvis and ureter, resulting in hydronephrosis. Long-term hydronephrosis will cause impaired kidney function on the affected side. Bilateral hydronephrosis may lead to uremia in severe cases. Whether a kidney stone has symptoms or not is related to the size of the stone. In some cases, even until the kidney on the affected side loses its function completely, the symptoms are still not obvious. The usual physical examination can be done by ultrasound and x-ray.