Summer is officially here. In addition to being the season for sun and fun, it’s the season for kidney stones.
Heat increases the likelihood that people become dehydrated. Dehydration leads to more concentrated urine, which can lead to stone formation by allowing for crystallization of minerals normally found in urine.
Kidney stones are generally asymptomatic until they start to pass from the kidney to the bladder. For the majority of people, passing a stone causes a great deal of pain, usually in the back and lower abdomen. The pain results from pressure in the kidney and ureter, which occurs when the stone obstructs the ureter.
An emergency room is where most kidney stones are diagnosed, as the pain generally is severe enough that patients will seek care there.
An initial evaluation for kidney stones includes imaging (most commonly a CT scan), a urinalysis, and blood tests with prescribed intravenous fluids and intravenous pain medications. Patients are sent home once their pain is controlled.
The majority of people will pass a kidney stone without requiring surgery, usually within a few days. Most stones are managed with pain medication and medications that relax the smooth muscle within the urinary tract, increasing the likelihood of passage.
Surgery is occasionally required to treat kidney stones. Indications for surgical intervention include stones that are too large or too numerous to pass, stones causing unimaginable pain, and stones associated with infection.
Most stones requiring surgical treatment require only a minimally invasive procedure. The two most commonly performed procedures are extra-corporeal shock wave lithotripsy (ESWL) and ureteroscopy.
Both require general anesthesia, but both are typically outpatient procedures and do not require a hospital stay.
ESWL is performed by focusing shock waves onto the stone and breaking it up into tiny fragments, which are then passed.
Ureteroscopy is performed by inserting a very small endoscope into the ureter and/or kidney and either removing the stone intact or breaking it into smaller fragments with a laser fiber and removing the fragments.
Up to one in 10 people in the United States will develop a kidney stone at some point during their lifetime. Traditionally, men are at higher risk than women for developing stones, but the risk for women is rising more quickly than the rate of risk for men, narrowing the gap.
Diet and the rising rate of obesity are suspected to be the primary contributors for the increase in risk seen in the U.S. Someone who has experienced a kidney stone has up to a 50-percent chance of forming another stone within the next five years. Up to one in four people with a history of kidney stones have at least one relative with kidney stones.
Calcium oxalate is the most common type of stone, comprising 85 percent of the total number of stones in the U.S. Other stone types include calcium phosphate, uric acid, struvite, and cystine.
Dehydration is among the most common contributing factors to stone formation. Anyone who has had a kidney stone should consume between 8 and 12 glasses of fluids daily, concentrating primarily on water, rather than soda or other beverages.
Dietary factors and genetics can also contribute to stone formation.
Dietary calcium is an uncommon cause of kidney stone formation, and it is generally recommended that patients with a history of stones maintain a diet with a daily calcium intake between 800 and 1200 mg.
Identifying a cause for a particular patient’s kidney stone includes having the stone analyzed along with a 24-hour urine test. Oftentimes, blood tests will also be necessary.
Excessive urinary calcium contributes to kidney stone formation in many patients. It can be caused by a defect in the way that the kidney handles calcium (known as a “renal calcium leak”) and can be treated with medication.
Other reasons for excessive urinary calcium include excessive dietary sodium and an overactive parathyroid gland, which is a small gland in the neck responsible for regulating our body’s calcium metabolism.
Occasionally, a doctor will recommend diet changes, depending on the evaluation. Too much sodium in the diet is among the most common causes of kidney stone formation in the U.S. Having an appropriate dietary sodium level can significantly reduce the level of calcium in urine, thereby decreasing the chance of recurrent stone formation.
For some patients, overconsumption of foods that are high in oxalate leads to stone formation, and their risk of further stones can be reduced by modifying their consumption of these foods.
Kidney stones are an unpleasant part of summer. If your urologist performs a proper evaluation and prescribes an effective management plan, stones don’t have to be a part of your summer! MSN
Dr. Todd Waldman is a provider at the Idaho Urologic Institute and Surgery Center.
