N23: Unspecified renal colic

The loin area is the area on both sides of your body between your chest and pelvic region.

Cramping loin pain can occur when the urinary passages are constricted or blocked. The urinary passages include the kidneys, ureters, bladder and urethra.

There are normally 2 kidneys in the body. They filter blood and create urine. They thus help to detoxify the body. Furthermore, the kidneys regulate the blood pressure and salt content in the blood, among other things. The ureter is a thin, muscular tube in the abdomen. There is usually one ureter on each side. The urine flows from the kidney, via the ureter, to the bladder. When you have to pass water, the urine flows from the bladder via the urethra and out.

If the urinary passages are constricted or blocked, this is often a result of urinary stones. Urinary stones can form in the kidney or the bladder. The urinary passages can also be blocked by blood clots or dead tissue, for example. If the urinary passages are blocked, urine can build up in the kidney. The ureter tries to squeeze the urine through the constriction by contracting and relaxing at regular intervals. The contracting of the ureter can result in painful cramps. You may also have blood in your urine as a result of urinary stones damaging the wall in the urinary passages.