Painful experience of acute renal colic is hard to define.

Columbia Icefield, Rocky Mountains (Dr. Noorali Bharwani)
Columbia Icefield, Rocky Mountains (Dr. Noorali Bharwani)

Renal colic is painful. The pain comes when urinary stones block part of the urinary tract. Kidneys are part of the urinary system. So are the ureters, urinary bladder and urethra.

Kidneys are very important organs in our body. We are blessed with two kidneys. If one kidney fails we have a spare one. Compared to other organs like brain, heart, liver and spleen. It is important we take good care of our kidneys. Two functioning kidneys are better than one.

Why kidneys are important? Because they remove waste and extra water from the blood in the form of urine. Without the kidneys, the waste would keep building up and, over time, you would die. Or go on a long-term dialysis until you find a matching kidney for a transplant.

There are many illnesses that can destroy the kidneys. Today, we will discuss the effect of kidney stones. Kidney stones have many causes and can affect any part of the urinary tract – from the kidneys to the bladder.

Some individuals are prone to forming stones in the kidneys or urinary bladder. Kidney stones are hard deposits made of minerals and salts. These include calcium phosphate, calcium oxalate and uric acid. Minerals crystallize and stick together. Supersaturation of the urine constitutes a driving force favouring stone formation.

Kidney stones are rarely, if ever, fatal. The main impact of kidney stones is felt by young, otherwise healthy adults in the form of acute renal colic, causing symptoms of pain, nausea, vomiting and blood in the urine.

The lifetime risk of passing a kidney stone is about eight to 10 per cent among North American males. The peak age of incidence is 30-years. The rate of kidney stone formation in women is about half that in men, with two peaks, the first among women aged 35-years and the second among those aged 55-years.

Among patients who have passed one stone, the lifetime recurrence rate is 60 to 80 per cent.

What promotes crystallization of chemicals in the urine? There are many factors involved in this process, including urine pH, stasis and dehydration. The whole process is complex, involving many factors.

A kidney stone may not cause symptoms until it moves around within the kidney or passes into ureter – the tube connecting the kidney and bladder. Passing kidney stones can be quite painful, but the stones usually cause no permanent damage if they are recognized in a timely manner.

Depending on the situation, you may need nothing more than to take pain medication and drink lots of water. In other instances – for example, if stones become lodged in the urinary tract, are associated with a urinary infection or cause complications, then surgery may be needed.

Some controversy exists about the extent of investigation required after the passage of a single stone. Because the rate of recurrence is high, some experts favour an exhaustive evaluation for anyone who has passed a stone.

Patients with kidney stones are advised to increase fluid intake to produce a urine volume of 2-3 L/day. Good advice is to reduce the intake of animal protein, calcium and sodium, because reduction in the renal excretion of sodium will also reduce renal calcium excretion and thus render the urine less prone to making stones.

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Kidney Stones

Dear Dr. B: I have a granddaughter, 20 years old, who had kidney stones at age17and is still periodically in discomfort because of them. It would be helpful to know foods to avoid for possible prevention, writes Mrs. M.

Dear Mrs. M: Pain due to kidney stone is a very unpleasant experience. I have seen patients roll in pain on the floor of emergency department. The pain may last minutes or hours. After a pain killer or sometimes spontaneously the pain goes away and everything is back to normal. As if nothing had ever gone wrong!

One out of ten Canadians will have a kidney stone at some point in their life. It is more common in men than in women. It is not that common in teenagers. Usually it affects people in middle age.

The urinary system is made up of the kidneys, the ureters, the bladder, and urethra. The system’s main function is to eliminate waste products in the form of urine. The urine contains many chemicals. When the chemicals form crystals, they tend to stick together. These crystals can grow into a stone ranging in size from a grain to a golf ball. The stones cause pain when they get stuck or pass through the urinary system.

Most stones contain calcium oxalate crystals. Some are uric acid stones or cystine stones. Some people seem to be more prone to kidney stones than others. This is due to several reasons: recurrent urinary tract infections, drinking too little fluid, blockage of the urinary tract, confinement to chair or bed for prolonged periods, consuming diet rich in calcium oxalate or uric acid, too much of vitamin C or D, certain medications and metabolic illnesses.

The stone, when passed or removed, should be sent for chemical analyses. This will help in planning diet and preventive measures. About 20 percent of patients have no definite cause for stones and the best treatment for them appears to be high fluid intake. The majority of patients with kidney stones have treatable metabolic disorder that can be detected by blood and urine tests.

Certain medications can help dissolve kidney stones except the ones with calcium. Unfortunately these are the commonest type. Small ones pass spontaneously. The ones that do not pass are blasted by high energy shock waves (Lithotripsy). Stones larger than 2 cm require surgery.

How can we prevent kidney stones?

Kidney stones recur in about 50 percent of cases. Therefore it is important to take preventive measures to avoid some very painful moments and prevent permanent damage to the kidneys.

Drink plenty of water during the day and at night. Drink plenty after meals and exercise. Patients with calcium oxalate stones should avoid large amount of dairy products and foods high in oxalate content (tea or chocolate). Avoid large doses of vitamin C (4 grams or more daily) and avoid heavy use of antacids.

If you have uric acid stones then cut down on the amount of red meat you eat.

This is just an over view of preventive measures. You should see a urologist for definitive answers to a specific problem.

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