Renal colic is caused by renal calculi (stones) as they pass through the ureter to the bladder.
Renal stones may remain in the kidney or can travel spontaneously through the ureter and into the bladder where they pass out through the urine
The pain, which is caused by ureteric muscle contraction in an attempt to move the stone, is often severe and has been compared to childbirth!
The pain is due to ureteric muscle contracting in an attempt to shift the stone.
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