Renal colic describes the pain arising from obstruction of the ureter, although ureteric colic would be a more accurate term. The pain is caused by spasm of the ureter around the stone, causing obstruction and distension of the ureter, pelvicalyceal 1 system and renal capsule.
Although the most common cause is a stone, the term “renal colic” actually refers to a collection of symptoms attributed to the kidney and ureter. There are other intrinsic or occasionally extrinsic causes such as lymphadenopathy, although extrinsic causes tend to present with milder and more chronic discomfort. Other common intrinsic causes are blood clots (from upper tract bleeding) or sloughed renal papilla (which can occur in sickle cell disease, diabetes, or long term use of 1 analgesics). The underlying cause of acute flank pain is not always a urinary stone and other important conditions can mimic this. A thorough history, examination and investigations are important to 1 determine further management.