Kidney Stones

Kidney stones form when the concentration of calcium salts and various other chemicals in the urine gets too high. Crystals precipitate in the urine and then aggregate to form stones. While usually a slow process taking months or even years, stones can sometimes form in just a few weeks. 

Urinary stones become symptomatic when they cause bleeding or obstruction to the flow of urine. Small stones in the kidney are frequently asymptomatic. When they just sit in the kidney with no movement or blockage they are pain free, and may be so for years. However, when the stones significantly increase in size or pass out of the kidney into the tube (ureter) carrying urine to the bladder, the stone may block the flow of urine which causes distension of the kidney and pain. As stones move and approach the bladder, they may cause frequent urges to urinate as well as burning with urination. Many small stones will spontaneously pass. However, as the size of the stone increases, the likelihood of stone passage decreases. Predicting the likelihood of passage requires knowing the exact size and specific location of the stone. X-rays, CT scans, and ultrasounds are commonly used to get this important information.

Stone pain usually comes on suddenly, with the hallmark being “colic,” which is pain plus nausea. The pain usually begins in the flank on the side where the stone is located and migrates to the groin area as the stone moves. The pain is often accompanied by severe nausea and vomiting. When passing a stone, remember to urinate thru a strainer so that you can capture the stone and we can be certain that it has passed. Never just assume the stone is gone because the pain has stopped. If there is any question, make sure to follow up with your doctor, because it can be dangerous to leave a stone blocking off the kidney.

Diagnosing Kidney Stones

Kidney stones can be diagnosed easily and quickly if the right tests are available. CT Scan has become the gold standard in the evaluation of kidney stone disease. Most urologists schedule CT scans through a hospital facility, but the Conrad Pearson Clinic has its own CT scanner right in the office. This allows for immediate evaluation for suffering patients who suspect kidney stones. Other tests may include IVP (intravenous pyelogram). For this test, contrast dye is given intravenously which circulates thru the kidney system. Plain x-rays are taken sequentially, which give a roadmap of the urinary drainage system. Such information can help decide the size, location, and blockage associated with stones or other kidney abnormalities. Urinalysis can detect if there is any blood in the urine, as stones in the kidney system will usually scratch the lining causing some bleeding. While not definitive, urinalysis can help confirm the diagnosis.

Treatment Options for Kidney Stones

Once a stone has been diagnosed, the urologist and patient have several options for addressing the problem. Factors that determine which method of treatment is best for a given situation include stone size, stone location, and the presence of any infection or anatomical abnormalities of the urinary tract.

Trial of Passage

Patients that have small stones (usually less than 5 mm) whose symptoms are well controlled with oral pain medications are frequently treated with a period of observation to allow the stone to pass. Commonly, we will suggest giving 3-5 days to see if it will pass, sometimes even longer if pain is well controlled. Larger stones or stones accompanied by severe symptoms usually require intervention. Medications, like Flomax, can be used temporarily to help dilate the system so stones may pass more easily. Pain medications and nausea meds are commonly needed while trying to pass the stone.

Lithotripsy

The first choice of treatment for most stones in the kidney is shock wave lithotripsy. This treatment utilizes a special machine (lithotripter) to generate a shock wave that has its energy focused on the stone. The shock waves pass easily thru the body and fragment the stone. Smaller pieces, often dust, are then much more easily passed in the upcoming days. Short acting anesthesia in the ambulatory surgery center makes this minimally invasive treatment virtually painless. The Conrad Pearson Clinic has one of the latest generation lithotriptors and the entire process usually takes less than an hour. Lithotripsy is the most common form of therapy, but some stones are not good candidates for lithotripsy.

In addition, you must be off any blood thinners for lithotripsy to be safe.

Ureteroscopic Stone Extraction

Stone extraction involves using a delicate scope to look into the urinary system. With the patient under anesthesia, a scope is guided into the opening of the urethra and gently up thru the urinary tract. When the stone is seen, a fine basket is used to grasp it and extract it. If needed, a high-tech laser can be used to break it into smaller pieces. Scope extraction is generally recommended when the stones are small and relatively low in the urinary tract. This procedure is performed in an outpatient surgery center or hospital under anesthesia.

Percutaneous Stone Extraction (PERC)

In cases where the stone is particularly large (over 20 mm) or is unsuccessfully managed by other treatments, percutaneous stone extraction may be recommended. This is done in the hospital and often requires an overnight hospital stay. At the hospital, a needle and wire are placed thru the skin of the back into the kidney system. This gains access to the kidney. In the operating room, that access tract is stretched so that instruments can be placed into the kidney to break the stone.

in the skin. A drainage tube may left in place overnight, which is removed before going home. Such PERC removals are rarely needed as most stones will respond to either lithotripsy or ureteroscopy.

Open Stone Surgery

In very rare circumstances, open surgical exploration or laparoscopic surgery is needed. Sometimes this is warranted if other problems exist with the kidney that need to be corrected in addition to the stone. If laparoscopic and robotic options are ruled out, the stone may need to be removed thru an old-fashioned surgical incision made in the flank. These patients recover in the hospital for several days, and have restricted activity in recovery of 3-4 weeks.

Stents

Sometimes in the course of managing a stone, the doctor will decide that a stent is necessary. The stent is a plastic tube that is inserted inside the urinary tract to relieve blockage. The stent spans the ureter from the kidney to the bladder. It is roughly the diameter of a spaghetti noodle and is about 12 inches in length. It is flexible and hollow like a straw. Many different circumstances may necessitate a stent. In some cases a stent is put in as a first step in treating the stone. The stent can gradually dilate the ureter over 5-7 days and make more room for the stone to pass or for a scope to be used later. Stone manipulation after stenting is much more reliable and effective. In other situations, the narrow natural anatomy will just not accommodate the ureteroscope to reach the stone. To force the scope up a narrow ureter is dangerous and can permanently damage the ureter. In these cases, the urologist will place a stent and come back a week later to more safely reach the stone. When there is infection in the urinary system, it is dangerous to manipulate stones as it may precipitate sepsis; therefore, when infection is present, a stent is placed to relieve the blockage and antibiotics are given for a week before further attempts are made at removing the stone. Finally, in many cases the ureter has become so irritated by the stone, that even though the stone is extracted, the ureter needs a stent for 4-7 days to assure proper healing. If the ureter is severely irritated upon removal of the stone, it will spasm and swell shut in the hours after the stone is removed and hurt just as bad as a stone. The stent is less aggravating than that would be.

When in place, the stent itself does irritate the kidney and bladder. Because it is plastic, the stent will rub the lining of the bladder and often causes blood in the urine. This amount of blood, while easily visible, is only a minor concern. Remember, a single drop of blood will turn the entire toilet bowl red. The stent might also cause spasms of the bladder and a constant urge to urinate. There are medications that can be taken to control spasms if needed. Once the stent is removed, everything returns to normal in 24-48 hours.

Stones and Sepsis: If a stone is infected and the patient is having fever and chills, special emergency precautions must be taken to avoid sepsis (overwhelming, life-threatening spread of the infection). Infection might develop at any time while managing a stone. Because infection can easily be aggravated in the urinary tract, attempting removal of an infected stone is not recommended. Instead, patients are usually hospitalized and either a stent or a nephrostomy tube is placed. A nephrostomy is a tube placed thru the skin of the back directly into the kidney by interventional radiologists in the hospital. The infected urine can then drain out of the kidney thru the tube. At a later date, once the infection is resolved, the stone can be safely treated and the stent or nephrostomy removed.