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Urology

Kidney Stones

Kidney stones are a very painful condition that affects both men and women. Once kidney stones start to form, they usually increase in size. Small stones may pass with the urine without being noticed. However, if they do not pass, they may stay in the kidney and grow larger. As long as they stay in the kidney, they don’t cause problems, but once they move into the narrow tube connecting the kidney to the bladder, called the ureter, they become very painful.

It is not unusual to go to the hospital or emergency room in pain. The physician may suspect a stone if you are having acute lower back pain, blood in urine, or a history of similar symptoms. Your physician will request a CT scan, the best way to discover a stone. Once the CT scan reveals the size of the stone, your physician will determine if it is possible to pass it out of the body naturally, or if the stone requires special treatment (discussed below). If the stone is less than 4 mm (smaller than a pea) there is a good chance it can pass naturally. These remedies will help:

  • Hydration - The more fluid you take in, the more likely the stone will push out.
  • Alpha blockers will relax the ureter between the kidney and bladder where the stone is stuck and increase the chance of allowing the stone to pass.
  • Pain medication will address pain as the stone moves.
  • Nausea medication can help when the stone causes intense pain.

Additional Information about Kidney Stones

Treating Stones that will Pass Naturally

Stones that do not pass naturally through the urinary tract may become stuck in the kidney and even block urine flow. This pressure is what causes the intense pain called ‘renal colic.’

If the stone is located near the kidney, a shock wave therapy may be used. This is a non-surgical method of breaking up the stone, which is very brittle.

A distal stone is located in the ureter between the kidney and bladder. A ureteroscopy is performed using a camera to look into the ureter. General anesthesia is applied, although no cuts are made. When the stone is found, a tiny fiberglass fiber is used to break up the stone.

Why do Stones Form?

The kidneys’ job is to filter the blood. This process produces about 50 gallons of urine every single day. The kidney then concentrates the urine down by reabsorbing water back into the bloodstream, more or less, depending on how much fluid you drink, and leaving solids called compounds. If you do not drink enough fluids, your urine will contain more compounds and will not dissolve in the volume of water provided.

Commonly Found Stones

  • Calcium oxalate stones form when the concentration of these compounds in urine is too high and there is not enough water to dissolve them.
  • Crystallization stones form when a small crystal of uric acid gets lodged in the body, for example, a suture left after an operative procedure, or anatomic variation of the kidney’s inner structure. In any case, small imperfections will produce the seed for kidney stones and dissolved compounds to come together and form a solid.

How can Stones be Prevented?

Stones are very common. If any stone or fragment is recovered, it is usually sent for analysis. If you have more than one stone, it is also important find out what may have caused it. A simple set of tests will help to find out what may have caused the stone to form. Once this is known, more specific ways to prevent further stones to form can be concluded.

Hydration

The most important thing you can do to prevent stones is to drink lots of fluids. This will make the stone-forming compounds (such as calcium and oxalate) less concentrated in the urine and prevent them from clumping together to build a stone.

Common Compounds

  • Calcium - Calcium is a very important ion for the human body and if it gets out of balance, our muscles start to cramp and our nervous system gets out of sync. That is why the body regulates how much calcium ends up in the bloodstream - no matter how much we take in - and how much is then put in the urine by the kidneys.
  • Oxalate - Oxalate is a compound found in many foods. Unlike calcium, it is not regulated by the body; the more you take in by mouth, the more is going to be left in the bloodstream. The kidneys get rid of the excess oxalate through the urine. So in the case of oxalate, reducing intake will actually reduce the risks of kidney stones. Calcium will also “bind” with oxalate and help it leave the body.
  • Salt and Sugar - Excess sugar and salt are factors that may increase the chance of developing a kidney stone.

Foods that Prevent Stones

Certain foods have nutrients which can prevent stones, citrate is the most important. It binds with calcium in urine and does not form a solid. Citrate naturally occurs in oranges and lemons.

Drinks which have shown to prevent stones in a recent study include orange juice (12%), caffeinated coffee (16%), tea (11%), wine (31-33%), and beer (41%).

Uric Acid Stones

This is the second most common cause for kidney stones. These are especially tricky since they are frequently not seen on plain xrays. CT scans can detect them, though.

Uric acid forms when genetic material (DNA) is broken down during digestion. Everything contains DNA and plant material produces less uric acid than meat. So, to prevent uric acid stones, it is better to eat more vegetables than meat.

For people who don’t regularly form uric acid stones, a change in diet may be enough. But when uric acid stones recur, medication may be prescribed which is able to stop uric acid to be produced in the first place.