By Alexei Wedmid, MD
Every year, more than a half-million Americans seek emergency medical treatment for kidney stones, according to the National Kidney Foundation.
For anyone who has experienced the searing pain of a kidney stone, it is something that is hard to forget. Women who have experienced both childbirth and kidney stones often say the pain caused by kidney stones is worse, research shows.
While some patients may be lucky to pass stones with little pain, some may need medical assistance and others may require surgery to remove the stone.
About Kidney Stones
Kidney stones are hard, stone-like objects made of minerals and salts that are normally dissolved in the urine. If urine has high levels of these minerals and salts, however, crystals can begin to form and eventually grow into stones.
The majority of stones — 80 percent — are made of calcium oxalate and are typically caused by too much calcium in the urine. Calcium stones can also form in people with normal calcium levels in the urine.
Less common are:
• Uric acid stones. People with acidic urine are at greater risk for these types of stones. Having acidic urine may come from being overweight, type 2 diabetes, and a diet high in animal protein and low in fruits and vegetables.
• Struvite/infection stones. These stones are related to chronic urinary tract infections.
• Cystine stones. These are a rare type of stone that often starts to form during childhood.
Kidney stones are rarely life-threatening, but if left untreated, some stones can cause infection and kidney damage.
Risk Factors
As the American Urological Association notes, Caucasians are more likely to get kidney stones than other races, and men are more likely to develop stones than women.
Other common risk factors are:
• Low urine volume. When volume is low, urine is concentrated, meaning there is less fluid to dissolve minerals and salts. Low urine volume is caused by dehydration often associated with hard exercise, working or living in a hot place, or not drinking enough fluids.
• Diet. Diets high in salt may keep calcium from being reabsorbed into the bloodstream. Additionally, eating foods high in oxalate such as beef, fish, chicken and pork, can raise acid levels in the urine, making it easier for stones to form.
• Bowel conditions. Bowel conditions such as a Crohn’s Disease or ulcerative colitis can cause diarrhea and consequently, dehydration, leading to low urine volume.
• Obesity. Obesity may change the acid levels in urine, leading to stone formation.
• Medication. Some medications, as well as calcium and vitamin C supplements, can increase the risk for stones.
• Family history. The chance of developing kidney stones is higher if your parents or siblings have a history of stones.
Symptoms
People typically don’t know they have stones until they start to pass. A stone can be silent in the kidney for years, and then suddenly fall down the ureter (the tube connecting the kidneys to the bladder), causing severe pain and other symptoms.
Common symptoms of kidney stones are:
• A sharp, cramping pain in the back and side, often moving to the lower abdomen and groin. The pain often starts suddenly and comes in waves.
• Feeling an intense need to urinate.
• Pain or burning when urinating.
• Reduced ability or inability to urinate.
• Signs of blood (pink, brown or red-tinted urine).
• Nausea and vomiting.
If you experience the symptoms of a kidney stone, seek immediate medical attention.
Kidney stones may also be discovered incidentally, during diagnostic testing for an unrelated condition. In those instances, it is wise to consult with a urologist, who can determine if treatment is necessary.
Diagnosis and Treatment
Kidney stones are normally diagnosed through imaging tests, including X-rays, ultrasounds, and CT scans.
If a kidney stone is small and not causing a blockage, medication can be prescribed to help the muscles in the ureter relax, so the stone can pass more quickly and with less pain.
A larger stone may be treated with a procedure called a lithotripsy, which uses shock waves to break it into tiny pieces that can pass more easily with the assistance of those same medications.
In cases where surgery is required because of the stone’s size or location, surgeons at Penn Medicine Princeton Health generally use endoscopic procedures in which the surgeon removes the stone from the urinary channel without any incisions. Following these procedures, a thin tube or stent may be inserted to help your kidneys drain easily.
In rare cases, if less invasive procedures fail, then open, laparoscopic or robotic surgery may be used.
Prevention
Although it is unclear why, some people are predisposed to making kidney stones. For frequent stone makers, doctors can perform lab testing on a passed stone and urine sample to help with a diagnosis. These tests can also identify any dietary or metabolic conditions that should be addressed to help reduce the likelihood of new stones forming.
To reduce the risk of kidney stones:
• Drink at least three liters of water a day. Your daily target urine amount should be 2.5 liters, and your urine should appear clear or near clear.
• Reduce the amount of salt in your diet. The Centers for Disease Control and Prevention advises eating no more than 2,300 mg of salt a day.
• Keep an eye on the amount of high-oxalate foods you eat, including chocolate and leafy greens. Talk to your doctor before making any dietary changes. Eating a healthy, balanced diet is key to overall well-being.
• Eat the recommended amount of calcium. If you take calcium supplements, make sure you are not getting too much calcium. According to the American Urological Association, you can normally get enough calcium from your diet by eating three to four servings of calcium-rich foods, such as low-fat milk, yogurt, and cheese, daily.
To find a physician with Penn Medicine Princeton Health, call 888-742-7496 or visit www.princetonhcs.org.
Alexei Wedmid, MD, is board certified in urology. He is a member of the medical staff at Penn Medicine Princeton Health.
