Kidney stones

Kidney stones

What are kidney stones?

Kidney stones are hard deposits that gather on the way from the renal pelvis in the kidney to the bladder. They accumulate in size over time, and though generally small, they can cause quite a lot of pain.

Kidney stones can provoke a severe, sudden pain if they move along the ureter, the tube leading from the kidneys, and they can cause a lot of health problems if they block the flow of urine. The pain can often be accompanied by vomiting. If they move into the ureter (the tube from the kidney to the bladder) they cause intense pain and blood in the urine.

Most people have kidney stones, but as they cause no difficulties, they may not know they have them. These are known as silent stones. One in 10 people will have a problem stone in their lifetime. White men are the most likely section of society to suffer from kidney stones, but people who have experienced kidney stones in the past are at risk of recurrence.

How do they form?

No one is sure how exactly kidney stones occur. What seems to happen is that the solids dissolved in the body's urine somehow become solid again and accumulate, growing over time into a stone, not unlike an oyster growing a pearl around a piece of grit.

If a kidney stone becomes lodged in the ureter, it may block the flow of urine to the bladder. If this occurs, the kidney, which is not designed to withstand pressure, may become damaged. If the stone lodges deeper down the ureter, the tube itself may become inflated with trapped urine. This causes the ureter to spasm, leading to a lot of pain.

If you have a kidney stone attack, you will probably require medical help. The stone, or calculus, may pass out of the body in the urine if it is small enough, but if it lodges you will have to attend hospital to have it removed.

How are kidney stones treated?

In the past, if a stone did not pass through the system, it was essential to have open surgery to remove the offending object. These days, the process of removing kidney stones is much less invasive. Most techniques involve inserting a disintegrating device through the bladder to break up the blockage.

Lithotripsy is a relatively recent development that is becoming the norm in kidney stone treatment. It uses ultrasound waves to break up the stones. The treatment is available at a number of Irish hospitals, and is becoming a favoured way of dealing with kidney stones, as it does not require any invasive surgery.

What are the warning signs of kidney stones?

Frequent urinary infections are often a sign of kidney stones, as is the appearance of fresh blood in the urine. Sometimes, however, the first sign of kidney stones is when they lodge in the ureter, causing a sudden, intense pain. If you experience any of these symptoms, you should consult your GP. Kidney stones are not life threatening, and are relatively easily treated, but they can cause immense discomfort if they are not dealt with.

How are kidney stones treated?

The majority of small stones will pass in the urine with relatively few problems. Bed rest, painkillers and a good fluid intake will help.

In the case of larger stones, or if infection or obstruction is present, surgical treatment may be necessary. Depending on the size and location of the stone this may require surgical removal through a special type of endoscope (a telescopic instrument inserted through the urethra and bladder up into the ureter). The stones may be crushed and removed through this tube. Other stones may be suitable for treatment by extracorporeal shock wave lithotripsy, where the stones are disintegrated by focusing shock waves on them from outside the body.

If an underlying metabolic disorder (such as gout) is detected, medical treatment and a special diet may be initiated to prevent recurrence of stones. However, no metabolic disturbance is detected in the majority of cases.

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