Renal colic is a painful condition that is closely related to urinary stones. It is not life-threatening but it can have a lot of unpleasant complications.
Renal colic is usually caused by urinary stones, which can obstruct a part of the urinary system (usually renal pelvis or a ureter) and stop the outflow of urine. The walls of urinary tract contain smooth muscles that begin reflexively contract in effort to push and remove the obstacle. These rhythmical contractions cause the colic pain.
Colic is designation for a sharp abdominal pain that comes in waves and is alternated by periods of calm. The pain is due to periodic contractions and relaxations of the urinary tract above the obstruction. The pain is strong and the patient may suffer from excessive sweating and vomiting. He or she is usually restless and tries to find a relief position, which is not possible. If the obstacle is in the upper urinary tract, the abdominal pain is located in the upper abdominal quadrant on side of the obstructed ureter and it may radiate to the back. When the obstruction is lower, the pain may radiate toward the groin. Any injury of the urinary tract by the stone may result in blood in urine finding. Of course, there are also less common causes of urinary tract obstruction such as blood clots or local tumors.
When the obstacle is not removed, the urine may accumulate above the obstruction and cause hydronephrosis with a risk of irreversible damage of kidney function. The urine may also get infected by bacteria causing urinary tract infections.
A patient with such symptoms should be examined by an abdominal X-ray as many urinary stones (but not all) are visible. Abdominal ultrasound may show the area of obstruction and it is very efficient in confirming the dilation of renal pelvis and presence of hydronephrosis. Intravenous urography is another radiological examination when the contrast agent is administered intravenously and the doctors examine its passage through kidneys and urinary tract (including any stricture or obstruction).
In acute phase, it is possible to administer painkillers and antispasmodic medications (drugs causing muscle relaxation) to relive the pain. If there is a urinary stone, it must be removed to prevent any complications. The removal is usually done by urologic tools that are introduced through the urethra and some stones may be destroyed by a device producing very strong shock waves (so-called extracorporeal shock wave lithotripsy). When the obstacle can not be removed in the acute phase, the urologists often puncture the urinary tract above the place of obstruction to allow the urine to flow to prevent any complications due to urine accumulation. This artificial outlet is referred to as the nephrostomy.