Acute obstruction and the resultant urinary stasis (disruption of urine flow) can distend the ureter (hydroureter) and cause a reflexive peristaltic smooth muscle spasm, which leads to a very intense visceral pain transmitted via the ureteric plexus.

[1] Although this condition can be very painful, most ureteric stones under 5 mm size will eventually pass into the bladder without needing treatments, and cause no permanent physical damage.

In most cases, people with renal colic are advised to drink more water to facilitate passing; in other instances, lithotripsy or endoscopic surgery may be needed.

[citation needed] A renal colic must be differentiated from the following conditions:[3] Most small stones are passed spontaneously and only pain management is required.

[citation needed] There is typically no antalgic position for the patient (lying down on the non-aching side and applying a hot bottle or towel to the area affected may help).