Pain in patients with ureteral stones is mainly caused by stone irritation of the ureter causing spasm of the ureter as well as blockage of the ureter by the stone. The sudden disappearance of pain may be due to the expulsion of the stone from the body or the stone has become embedded.
1. Stone expulsion: If a relatively small stone is expelled from the body, the stone’s stimulation of the ureter suddenly disappears, and the pain will disappear.
2. Stone impaction: if the stone stays and impounds in the narrow position of the ureter during its descent down the ureter and stops moving for a short period of time, the pain may also disappear suddenly in this case.
Overall, the sudden disappearance of pain in patients with ureteral stones does not fully represent the discharge of stones from the body, and need to go to the hospital in time to do ultrasound or CT examination to clarify the cause and then targeted treatment.