Kidney stone disease is one of the most common and painful urologic conditions. It has been estimated that 1 out 11 people in the US have had a kidney stone (11% of men and 7% of women). The economic costs are estimated to be over $2.1 billion annually, and the incidence is increasing!
Stones can range in size from a grain of sand to golf ball size. Fortunately, most stones pass without intervention, but some patients require surgery to treat the condition.
What Causes Kidney Stones?
Stones form from an imbalance of minerals and other substances in the urine. If the urine is too concentrated, crystals form and eventually grow into stones. The majority of stones contain calcium in combination with oxalate or phosphate, and other substances that form stone include struvite (from infections), cystine and uric acid.
What are Common Symptoms of a Kidney Stone?
A stone in the kidney only rarely causes any symptoms. Symptoms typically result when the stone passes down from the kidney into the ureter, causing obstruction to the kidney. Symptoms can include flank or abdominal pain, hematuria, and nausea and vomiting. If the stone is near the bladder, urinary frequency and urgency can result. Fevers can accompany a kidney stone if a UTI is also present and may be an emergency. Rarely, the stones are “silent” and do not cause any symptoms.
Who is at Risk for Kidney Stones?
Stones are more common in men, people of Caucasian race, people ages 20-60 years old, those with family or personal history of stones, and those with poor diet (high in salt, calcium, protein, oxalate or with low fluid intake), metabolic syndrome, inflammatory bowel disease (such as Crohn’s), and frequent UTIs.
How are Stones Diagnosed?
A CT scan is most often performed to diagnose kidney stones. An Xray may also show calcium containing stones, and ultrasound is used to monitor patients who have a history of kidney stones.
How are Stones Treated?
In most cases, the preferred treatment for kidney stones is either medical expulsive therapy or a trial of passage. Most stones can pass without intervention, using medications to manage pain and facilitate stone passage. If surgery is needed, the following procedures are available:
Extracorporeal Shockwave Lithotripsy (or “ESWL” for short)
ESWL is the least invasive surgical procedure to treat kidney stones. In this procedure, shock waves are passed through the body until they reach the stone. The stone is then fragmented into pieces that the body flushes out. This works best on stones that are in the kidney or proximal ureter. Large stones, multiple stones, or hard stones may require more than one treatment.
ESWL can be performed in our Lake Barrington facility as an outpatient procedure. This procedure typically takes about 45 minutes and is done under intravenous anesthesia. Your urologist focuses the shockwaves on the kidney stone using periodic X-rays taken during the procedure. Blood in the urine is common and self-limited. Severe bleeding around the kidney happens only very rarely. It is common to have some discomfort from the procedure and later, as the tiny stone fragments are flushed out of the body. In some cases, a temporary ureteral stent is placed to allow the fragmented pieces to pass more easily. Severe pain is unusual. Rarely, the stone fragments can be too numerous or too large for the kidney to flush out, requiring additional procedures to remove or fragment them. There is a theoretical risk of inducing high blood pressure from the procedure though evidence on this is inconclusive.
Ureteroscopy with Laser Lithotripsy or Stone Extraction
Ureteroscopy is when a small telescope is placed into the urethra, bladder and then up the ureter and kidney to the stone. A tiny laser fiber can then be used to fragment the stone to dust and debris that the kidney then flushes out. Stones can be grasped with a basket-device and removed in entirety if they are small. This works best for small stones that are distally located (in the portion of the ureter closest to the bladder). This is an outpatient surgery done under general anesthesia. Patients typically have more discomfort in the kidney and the bladder then with ESWL, may see blood in the urine, and may feel the urge to urinate more (especially if a temporary ureteral stent is placed to facilitate fragment passage and healing).
Percutaneous Nephrostolithotomy (PCNL)
PCNL involves accessing the kidney directly through a puncture hole in the back. An endoscope is then used to visualize the stone and guide an ultrasonic device or laser fiber to fragment it. This is more invasive then the above procedures and requires a general anesthesia and short hospital stay. The risk of bleeding is higher with this procedure, and it is generally preferred in cases of large kidney stones.
How can Kidney Stones be Prevented?
In many patients, dietary factors are the main cause for kidney stones. For some, dietary changes or medications are recommended. Urine and blood tests are typically recommended to pinpoint specific causes for each patient. More than one half of patients who have one stone may have another stone in their lifetime, so prevention is key.