Stones create tears in the lining of the ureter, but most pain is created from the back up of fluid into the kidney. Fluid fills the kidney, and pain to the flank on the effected side is created. Movement of the stone down the ureters until they lodge and eventually obstruct another area of the ureter, creates the sensation that the pain moves to the abdomen and groin area. Sensations of urgency and frequency develop if the stone becomes lodged where the ureter joins into the bladder. Stones passing into the bladder rarely cause pain.
Treatment includes management of the pain to help the patient relax.
Narcotics relieve pain by scrambling messages in the spinal cord. Additional use of anti-inflammatory medications to relieve swelling and stop the production of pain mediators at the site is helpful. Increased fluid intake by IV or oral routes helps to push the stone past the area that is obstructed. When pregnant, kidney stones are more easily passed because the ureter is dilated. Stones rarely will cause an obstruction, although they can alter the flow of urine and cause infection.