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The Kidney Stone Center
The Kidney Stone Center
The Kidney Stone Center is a multidisciplinary collaboration between Urology and Nephrology, which provides a comprehensive approach to the diagnosis, treatment, and prevention of kidney stones. When patients think of getting treatment for kidney stones, they usually think of the endoscopic procedure required to remove the stone from the body. At the Parkland Kidney Stone Center, the approach is comprehensive. Nephrologist Ana Stankovic, MD, specializes in analyzing componenets of the blood and urine with the aim of identifying abnormalities that, when treated, can prevent or decrease stones from forming in the future.
Kidney Stones Overview
Normal amounts of minerals, crystals, and electrolytes remain dissovled in the urine. When these components separate from the urine (for example with dehydration) instead of staying dissolved, kidney stones can form. These are hard crystal deposits that form in the urine collection chamber in the center of the kidney. Kidney stones may be painless and cause no symptoms when they sit inside the kidney. If the stone drops down into the ureter tube which carries urine down to the bladder, it can block the flow of urine, which is intensely painful. Treatment of kidney stones depends on the size, number, and location of the stone(s), as well as associated symptoms.
Frequently Asked Questions
What is a kidney stone?
A kidney stone is a hard crystal made from substances in the urine which forms in the inner collection chamber at the center of the kidney. These crystals can range in size from microscopic (can only be seen in a drop of urine under the microscope) to several centimeters in size. The most common type of stone is made from calcium crystals (combined with either oxalate, or phosphate).
Who gets kidney stones?
Certain factors may increase the likelihood of developing a kidney stone. These include relative dehydration (not drinking enough fluids on average over many years), taking too much or too little calcium, and eating foods with high animal protein levels. Medical conditions such as hyperactive parathyroid, gout, Crohn’s disease, and other intestinal problems causing excessive diarrhea can also lead to kidney stone formation. Patients who have undergoing bariatric surgery (gastric bypass or banding) are also prone to kidney stone formation. Other patients may have no risk factors that the doctor can identify.
I have gallstones. Is that the same thing?
No. Gallstones are unrelated to kidney stones.
What are the symptoms of kidney stones?
In general, kidney stones that are sitting in the kidney not causing blockage will not cause symptoms. In fact, a patient may not know they have kidney stones unless they are picked up by accident on a radiology scan. However, if a stone “passes” it falls down into the ureter tube, blocking the passage of urine from that kidney. The urine trapped in the kidney is under pressure, and this causes intense pain in the flank (mid-low back). This pain can move or radiate around the front to the lower abdomen, or even down to the scrotum in men. The pain typically comes in waves (colic). The pain may be associated with nausea and vomiting. If the stone rubs along the urinary tract lining, blood in the urine may appear. If the urine trapped behind the stone becomes infected, kidney stones may be associated with a high fever and/or shaking chills.
How are kidney stones diagnosed?
Kidney stones may be suspected based on suggestive symptoms, prompting the doctor to order some type of radiology scan (including ultrasound, plain x-ray, or CT scan). Alternatively, a stone may be found incidentally on a scan performed for another reason. Not all stones are visible on each type of picture, for instance some types of stones are invisible on plain x-ray. In general, the vast majority of stones can be seen on an abdominal CT scan. The results of the scan will help to determine what, if any, treatment is required.
What are the treatments for kidney stones?
Treatments for kidney stones are different depending on whether a patient is having an emergency acute “attack,” or if elective treatment is being planned on a scheduled basis. Sometimes, dietary and lifestyle modifications are required to treat asymptomatic kidney stones, such as drinking more fluids and avoiding certain foods. In other cases, medications are prescribed to dissolve the kidney stone.
During an acute episode of stone blockage, pain medications are prescribed, as well as other medications that speed up stone passage are often prescribed. With such a strategy, some patients are able to pass the kidney stone on their own at home. They may be asked to urinate through a filter to “catch” the stone so that it can be analyzed.
Sometimes, surgical intervention is required for a kidney stone. In general, scheduled procedures to remove a kidney stone include shock waves, ureteroscopy, and percutaneous nephrolithotomy (PCNL). [link to procedures below] A urinary blockage from a kidney stone with a simultaneous urinary infection is a serious and even dangerous combination, requiring urgent treatment to relieve the blockage and strong intravenous antibiotics.
What is shock wave lithotripsy?
This procedure requires no incisions. In shock wave lithotripsy, shockwaves are generated by a machine outside the body, and targeted towards the stone. The shock waves cause the stone to fragment into tiny pieces, which pass out of the body in the urine. The shock waves are targeted to the stone precisely, using either x-ray or ultrasound guidance. This is usually an outpatient procedure, but does require at least a mild anesthetic (sedation). The main risks of the procedure are incomplete stone fragmentation (denser or harder stones are less likely to break up), blockage from stone fragments becoming lodged in the ureter tube, and bleeding from the kidney.
What is ureteroscopy?
This procedure requires no incisions. Under general anesthesia, a small camera is inserted into the bladder. An even smaller camera is threaded backwards (opposite the flow of urine) up the ureter tube. The camera (called a ureteroscope) is passed up the tube until the doctor encounters the stone under direct vision. The camera has a small channel through which instruments can be passed. A tiny laser fiber can be used to fragment the stone into tiny pieces. Then a small basket is used to grasp the tiny stone fragments and “fish” them out of the kidney and/or ureter tube. Sometimes, the procedure itself can cause swelling, and this swelling blocks urine form passing even when the stone has been removed. To prevent this, a flexible plastic tube called a stent (link to question below) iis left in place so that the urine can pass freely from the kidney to the bladder even if there is some residual swelling from the procedure.
What is PCNL?
For this procedure, a small skin incision is required. PCNL stands for percutaneous nephrolithotomy. The largest stones need to be removed using this technique. As it turns out, the kidneys are fairly close to the skin of your back. Under general anesthesia with the patient lying on their stomach, a small skin incision (the size of a nickel) is made in the back over the kidney. Under x-ray guidance, the kidney is punctured in order to temporarily place a small plastic tube through the kidney into the inner urine collection chamber where the stone is located. This plastic tube serves as a tunnel or channel through which the surgeon can access the kidney. The stone is broken up into fragments which are removed through the plastic tube. At the end of the procedure, a drainage tube is left in the kidney temporarily (which drains urine into an external bag). Patients stay in the hospital for several days while they recover.
What is a stent?
A stent is a long, flexible plastic tube which is placed inside the ureter tube. The function of a stent is to allow urine to drain from the kidney to the bladder in cases where the flow of urine may otherwise be blocked. It is an effective way of relieving pain caused by a stone “attack” where the stone is causing blockage of urine flow from one kidney. In addition, a stent may be left in place at the end of a procedure to remove a kidney stone, so that urine can flow easily from the kidney while the swelling from surgical manipulation subsides. A stent cannot be seen from the outside. A stent can sometimes cause bladder irritation, leading to a feeling of urinary frequency and urgency to urinate. The word “stent” can often be confusing to patients because of other common “stents” that are placed elsewhere in the body. A urinary stent is not the same as a stent put in the heart to improve blood flow. While both are designed to relieve blockage, a urinary stent cannot be left permanently in the urinary tract.
Why is it important for me to have a urologist and a nephrologist?
The approach to kidney stones must be comprehensive. The goal should be threefold: (1) remove stones that are currently causing blockage or may do so in the future and (2) thoroughly analyze the kidney function and dietary/lifestyle factors contributing to stone formation (3) institute treatments aimed at preventing future stone formation. At Parkland Medical center, this is best accomplished by virtue of a partnership between a urologist and a nephrologist.
Does everyone who has a kidney stone require further testing?
No. Patients who have kidney stones several times require further testing. Children with kidney stones also benefit from further testing.