The acute pain caused by kidney stones often occurs suddenly. This happens when a stone, moving along with the urine flow, suddenly blocks the outlet of the renal pelvis or the ureter, causing urine to accumulate in the kidney and resulting in hydronephrosis. At this point, there is a sharp increase in pressure inside the renal pelvis, which can produce intense pain. This pain usually has no obvious warning signs and, once it appears, progressively worsens in a paroxysmal manner. Patients need to go to the hospital immediately for symptomatic treatment, such as intramuscular injection of analgesics, extracorporeal shock-wave lithotripsy,... Learn more