Check-up: Marion Kerrexplains how kidney stones develop
You wrote recently about gall stones, but what about kidney stones? Perhaps you could explain what these are?
Kidney stones are small hard stones that form in the kidneys. They usually begin as a minute, sand-like piece of material which gradually increase in size. The developing stone is made up of substances found in urine, particularly calcium.
It is a process not unlike the manner in which a pearl grows in an oyster. Kidney stones can vary in size and while it's possible to have just one it is possible for several to develop.
Many stones are flushed out of the kidneys while they are still small, causing no problems. But others can remain, growing larger over a period of time. They can then make their presence felt when they move into the ureter, the tube that links the kidneys to the bladder.
I believe the pain of a kidney stone is unbelievable. What causes the severe pain?
Passing a large stone is very painful. This is thought to be due to the movement of the stone passing through the ureter, stretching the narrow tube and causing it to go into spasm. As the ureter contracts in response to the stone, it causes severe, cramping pain in the lower back or flank, which may also be felt in the groin.
For some, the first sign of a kidney stone is the onset of colicky pain and vomiting. The pain tends to last for a few hours, typically coming in waves and only resolving once the stone has passed into the bladder allowing the ureter to relax.
Occasionally a small amount of blood may be noticed in the urine. While a pain-killing injection is usually required, anti-inflammatory drugs are usually prescribed after the attack has settled to reduce inflammation in the tissues.
Can a kidney stone be blasted with a laser?
Depending on the size and location of the stone, it may pass through the urinary system itself or it may need some assistance. Removal of a stone may be possible using a small flexible scope called a uretheroscope. A treatment called lithotripsy which uses sound waves to shatter the stones may also be used. The resulting fragments are then flushed out and eliminated in the urine. Surgical removal of the stone may be necessary.