Question: I have just experienced the most excruciating pain of a kidney stone. Why do they hurt so much?
The kidneys sit in your loins at the side of your abdomen, just below the ribs. The urine from the kidney is collected into a relatively large chamber, which has a fine tube (the ureter) leading from it down the back of the abdomen to the bladder.
Everyone forms kidney stones, but most are less than a millimeter across and pass unnoticed. If the stone is slightly larger than the diameter of the ureter, it will be forced down the tube by the pressure of urine behind it, but will scratch the inside of this long tube causing the excruciating pain that runs across the abdomen to the scrotum and penis. When the stone is at rest, only a dull ache is felt. Once it starts moving and scratching the tube, severe pain (described as far worse than childbirth) occurs.
Once the stone passes into the bladder, it easily passes out when you urinate with no further pain. If the stone gets stuck in the ureter, surgery or other procedures are necessary to remove it.
Question: My wife wants to know what causes kidney stones and how can she avoid having more, as she has suffered great pain with them in the past.
The kidney acts to filter the blood, and removes excess water and wastes. If these wastes become too concentrated, or altered in some way, they can precipitate out and form a crystal that slowly grows into a stone. Once the stone has formed, one of three things can happen to it.
Most stones are flushed down the tube that leads to the bladder from the kidney (the ureter) and are passed out of the body with the urine while still microscopic in size. These cause no trouble at all, and you do not know that they have been present. A small number of stones may slowly and steadily grow in size until they are the size of a grape, or even a ping-pong ball. These big stones may completely fill the urine collection chamber of the kidney. They usually cause no trouble, but they may be the source of repeated kidney infections and pain.
The third group is the most troublesome. These stones, from one to five millimeters in length, can enter the ureter. This fine tube is very sensitive, and as the stone is pushed along the tube by the pressure of urine behind, ir scrapes the tube wall causing the intense pain that sufferer’s experience.
There is no simple way to avoid kidney stones, but drinking plenty of fluids (mainly plain water) will help flush the kidneys out regularly and reduce the chance of anything but the smallest crystals forming.