Kidney Stones: Risk, Treatment and Prevention

Wednesday, September 04, 2013 2:30 PM

Kidney stones can cause pain that ranges from mild to excruciating; however, stones typically do not cause symptoms until they move from the kidney into the ureter (the tube that connects the kidney to the bladder). So how do they form? Kidney stones develop when urine consists of more crystal-forming substances than the urine can dilute. Often there is no single definitive cause of kidney stones but there are factors that increase one’s risk for developing them. Determining the type of kidney stone can be helpful in determining its cause and preventing recurrence.
kidney stones
Main kidney stone types:

  1. Calcium stones. The majority of kidney stones are calcium stones, most often calcium oxalate. Oxalate is found in food, including nuts, some fruits and vegetables, and chocolate.
  2. Struvite stones. This type of stone is associated with urinary tract infections (UTIs). They are composed of magnesium and phosphate.
  3. Uric acid stones. These are the second most common type of stones. Risk factors include diabetes, obesity, hypertension, gout and a high-protein diet.
  4. Cystine stones. These stones form in patients with a rare hereditary disorder called cystinuria.

Amanda Macejko, MD, Urologist at NorthShore’s Jon and Carol Water Center for Urological Health, answered several questions about kidney stones, including hereditary risk factors, and how best to treat and prevent recurrence:

If there is a family history of kidney stones, are you at an increased risk for developing them at some point?
Stones can certainly have a hereditary component. So, yes, if there is a family history one could be prone to developing stones. One of the best things you can do to decrease your risk is to make sure you drink plenty of water (2.5-3 liters of water daily).

Is there a particular group of people who are at higher risk of developing kidney stones?
Peak incidences of stones occur in people between the ages of 30-60. Caucasians and people who live in warm, dry climates are at higher risk of developing stones. Additionally, people with higher body mass index (BMI) are also at increased risk.

Aside from drinking a lot of water, what other preventative measures can be taken to avoid recurrence of kidney stones?
The stone prevention diet includes: limiting salt intake, avoiding foods high in oxalates and limiting consumption of animal protein. Salt intake increases calcium in the urine so we recommend avoiding canned, processed and fast foods which contain a lot of sodium.

For people with calcium oxalate stones, foods high in oxalate should be avoided, which includes tea, spinach, nuts, and, I’m sorry to say, chocolate. Animal protein, including red meat, chicken, fish, should also be limited. It is important to note that calcium restriction is not recommended.

I've had multiple stones over the years, do I need further tests?
For someone with multiple stones or a strong family history of stones , I highly recommend a metabolic work up. This involves blood work and a 24-hour urine collection (48 hours the first time). This helps your physician figure out what your specific risk factors are for stone formation, as well as look for possible underlying medical conditions. We perform this service in the Stone Clinic which is staffed by myself, Dr. Park (urology) and Dr. Sprague (nephrology).

Can kidney stones cause renal failure?
Nonobstructing stones in general should not cause renal (kidney) failure; however, untreated obstructing stones may eventually cause renal impairment.

Should you always go to the hospital for kidney stones?
This is really important. If your pain is tolerable with pain medication, whether over the counter or prescription, then you can probably follow up with your primary care doctor or urologist in the office to work out a plan. However, if your pain is not well controlled or you have significant nausea/vomiting, you will need to go to the emergency room. Typically they will be able to control your pain and/or nausea and you can return home. Most importantly, if you have fever (higher than 100.5˚ F.) or shaking chills, you need to go to the emergency room immediately. An obstructing stone associated with an infection is very serious and can be life-threatening.

If someone has a kidney stone but would rather attempt to pass it at home, what can he or she do to ease the pain from home?
Most patients take some form of pain medication whether it be over the counter or a prescribed narcotic while they are passing a stone. Additionally, we often prescribe an alpha-blocker. These are the same medications used to increase the flow of urine through an enlarged prostate. These medications have been shown to help relax the ureters and increase the rate of stone passage.

What can be done for larger stones that cannot be passed on their own?
Kidney and ureteral stones that are too large to pass often require treatment. Common outpatient treatments include shock wave lithotripsy or ureteroscopy. Shock wave lithotripsy is a procedure performed under anesthesia in which we break the stone using sound waves. After the procedure you then pass the fragments. In ureteroscopy, a small scope is passed through the urethra and bladder and into the ureter. The stone is broken up with a laser fiber and the fragments are subsequently removed with a tiny basket.

Have you ever had a kidney stone? What do you do to prevent them?

 

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