Renal colic

Renal colic (literally, kidney pain), also known as ureteric colic (literally, pain in the ureters), is characterized by severe abdominal pain that is spasmodic in nature. This pain is primarily caused by an obstruction of one or both ureters from dislodged kidney stones. The most frequent site of obstruction is at the vesico-ureteric junction (VUJ), the narrowest point of the upper urinary tract. Acute (sudden onset) obstruction of a ureter can result in urinary stasis - the disruption or cessation of urine flow into the bladder. This, in turn, can cause distention of the ureter, known as a (hydroureter). The obstruction and distention of the ureter(s) results in reflexive peristaltic smooth muscle spasms or contractions, which then cause very intense and diffuse (widespread) visceral pain affecting the organs of the pelvis, abdomen and even the thoracic area. This intense, diffuse pain is transmitted via the ureteric plexus, a branching network of intersecting nerves that cover and innervate the ureters.