Kidney Stones
What are they?
Sometimes urine contains so much waste, it crystallises and forms small stones in the kidney. Most people's urine contains chemicals that stop the crystals from forming. However, some people's chemicals do not work efficiently, so crystals are made.
The most common cause of kidney stones is not drinking enough fluids, although they can also develop from longstanding urinary tract infections and prolonged bed rest.
Most stones start off the size of a small piece of gravel and if they remain tiny they will pass out of the body in the urine unnoticed. If the stones are large they can become very painful. However, it can take years before they grow to a size that is big enough to cause symptoms.
What are the symptoms?
Larger stones, or fragments of stones, can travel down the ureter (the tube from the kidneys to the bladder). This can cause extremely painful spasm of the wall of the ureter. This is called renal colic.
Symptoms can appear suddenly and include:
How is it diagnosed?
The doctor will first examine you and then test your urine for blood or signs of infection. He may also check your urine for signs of crystals and also test its acidity as this may help indicate what type of stone you have. You may also have an x-ray of your kidneys, as 90% of stones are visible on x-ray. This gives the doctor valuable information about the stone's size and location. If you have no symptoms, it is common for these 'silent' stones to be picked up only when an x-ray is performed for another reason, for example a general health examination.
The doctor may also scan your urinary system using a special x-ray test called an IVP (intravenous pyelogram). A dye is injected into a vein and then concentrated in the kidneys and passed into the urinary tract system so that more detailed images of the kidneys, ureters and bladder can be seen.
How is it treated?
If the stones are only small, and stay in the kidney, you may be advised to simply drink lots of fluids to help flush the stones out, rest and take painkillers to relieve the discomfort.
Extracorporeal shockwave lithotripsy
The most common treatment for kidney stones is lithotripsy. This is when shock waves, usually ultrasound waves, from outside the body travel through the skin and tissue until they reach the denser stones. The stones break down into a powder. This powder can be easily passed through the urine with little pain.
Ureteroscopic stone removal
A small tube is passed into the urethra, and up into the bladder and ureter. Through this tube, instruments can be passed that will remove or crush the stones.
Percutaneous nephrolithotomy
If a stone is very large or in a place that does not allow use of lithotripsy, this operation may be performed. The surgeon makes a tiny cut in the back and creates a tunnel directly into the kidney. Using an instrument called a nephroscope, the surgeon finds and removes the stone. If the stone is too large to remove in one piece, an energy probe may be used to break the stone into smaller pieces.
Open Surgery
Although much less common now, sometimes traditional open surgery is still required. Very large kidney stones can occupy the whole of the inside of the kidney and are known as staghorn stones. These may require open surgery.
Once the kidney stones have been treated, it is important to avoid them coming back. Steps that can be taking to prevent their return include:
