A Brief Primer on Kidney Stones

Kidney stones, or calculi, can form at any age but are more common in adults. Stones represent an imbalance of certain byproducts in the urine that when high enough can form little crystals, or early stones. Once a crystal forms, stones then develop over months to years. Stone disease tends to run in families, and up to 10 percent of the adult population will develop kidney stones at some point in their life.

It’s important to remember that kidney stones are not related to gallstones. They can form on the inside of either kidney, usually at night while we sleep, and are silent when growing. There are multiple urine and digestive byproducts that can bind together to form stones if high enough in concentration. Other urinary byproducts can actually prevent stones, but if these are abnormally low in concentration, they can also lead to stone formation.

Kidney stones can cause intense pain in the back or abdomen when they detach from the wall of the kidney, and are usually accompanies by vomiting or fever. This pain is caused when the stone blocks the ureter and obstructs the flow of urine. Most stones form when calcium binds to either oxalates or phosphates. Most are hard, but some are relatively soft. Others are made from uric acid, which can easily be dissolved. Unfortunately, only 10 percent of stones are uric acid while calcium stones comprise the majority.

Less common stones can form certain urinary tract infections, and some rare stones may be formed from the use of certain medications. Nearly all stones can be detected by a CT scan, which is the main x-ray used for diagnosis. A KUB film of the abdomen may also be done to determine if the stones are dissolvable, but it’s less sensitive in picking them up. Calcium stones cannot be dissolved and if they cause pain or if too large, must be removed. Small stones are given a trial of passage with pain medication and time.

There are medical and surgical treatment options available for kidney stones. If uric acid stones are present, they can be dissolved over time with certain medication, and prevented with another medication. Calcium based stones can either can be observed, crushed or removed.

Tiny stones don’t cause pain and are observed with periodic x-rays. If they begin to grow, they can be crushed. If the stones are small enough, usually less than five millimeters, and they drop from the kidney causing pain, some time is usually allowed to see if they will pass on their own prior to intervening. Pain medication and other medications may be administered to help the stones migrate from the ureter to the bladder. Once in the bladder, the stones have passed. Stone passage causes pain, blood in the urine and sometimes fever. Most people can pass small stones, but if the pain is too great, if infection is present, or if vomiting persists, the stones will be removed.

Shock wave lithostripsy is a noninvasive wave to crush stones, as long as they are big enough to be seen on KUB x-ray. Once broken up, the tiny fragments must then pass. If stones block the ureter and cause pain, a tiny, thin endoscope can be used to enter the ureter and remove the stones directly with a laser. Very large stones are occasionally removed with a scope through a small back skin incision.

Stone analysis gives us the composition, while blood work and a 24-hour urine collection will tell us the metabolic imbalances that caused the stones. Increasing fluids, dietary modification, adding certain supplements to your regimen and medication are all used to correct the imbalance and prevent future stones.

Matthew E. Karlovsky, M.D.
Center for Urological Services, P.C.
4545 E. Chandler Blvd, Suite 300
Phoenix (Ahwatukee), AZ 85048
480-961-2323 tel
480-961-2325 fax