By Daniel Hardison, Pharmacy Resident, Baptist Health Medical Center-North Little Rock
The kidneys are one of the more extraordinary organs of our body and without them we would not survive. They make up only 0.5 percent of our total body weight but can filter all the blood in our body in 30 minutes. This means that the blood gets filtered through our kidneys roughly 400 times a day.
The kidneys help regulate the body’s fluid level, filter waste and toxins from the blood, and help keep blood minerals in balance. However, when this waste becomes too concentrated or unbalanced in the urine, stones begin to form inside the kidneys. This is known as nephrolithiasis, or more commonly, kidney stones.
Kidney stones are small, hard mineral deposits that usually consist of either calcium, struvite, or uric acid and usually effect one in 10 Americans during their lifetime. The most common cause of kidney stones is an increased urine concentration allowing the minerals in the urine to stick to each other. Factors that increase the urine concentration include dehydration, certain diets, obesity, and other medical conditions.
Dehydration is a major risk factor for kidney-stone formation because there is less fluid to keep the minerals dissolved in the urine. Increasing fluid intake on a daily basis helps dilute these minerals. It is recommended to drink 2.5 to 4 liters of water daily to increase the amount of urine produced in the kidney.
Sugar-free lemonade or lemon-lime soda has also been shown to decrease the formation of stones by adding a chemical to the urine that keeps certain stones from forming. It is important to limit any other type of soda that is not sugar free.
Diets that tend to be high in protein, sodium, and sugar can increase the risk of stones. When there is too much sodium in the diet, the kidney has to filter more calcium, which can increase the concentration of calcium in the urine. It is recommended to limit sodium to 2,300 mg daily. It is also suggested to decrease the amount of proteins such as meat, cheese, and eggs because these can increase the level of uric acid in the urine.
Other diets rich in oxylate, a mineral found in some green vegetables, and high-dose vitamin C containing supplements may need to be limited due to an increased risk in stone formation. However, it is still recommend to eat plenty of fruits and vegetables because they provide other substances that help prevent kidney stones.
Obesity is one condition that has been shown to increase the formation of stones by causing the urine to be more acidic. Other medical conditions such as chronic diarrhea/inflammatory bowel disease, hyperparathyroidism, and urinary-tract infections have all been linked to kidney stone formation. These conditions play a role in the balance of sodium and calcium.
Some medications that have been associated with stone formation include phenazopyridine, amoxicillin, ampicillin, aspirin, triamterene, and ciprofloxacin.
Certain medications can be used to prevent the formation of certain types of stones. These include medications that help relax the bladder, decrease the amount of specific minerals in the urine, or help make the urinary conditions more favorable to prevent stone formation. These medications include thiazides, allopurinol, potassium citrate, and potassium magnesium citrate.
Kidney stones can affect any part of the urinary-tract system from the kidneys to the bladder. This may cause someone to experience different signs and symptoms of kidney stones. Notify your doctor right away if you are having severe pain with nausea, vomiting, fever, or chills, blood in the urine, or have a difficulty passing stools.
Smaller stones can be treated in the doctor’s office or are passed in the urine without difficulty. However, larger stones may require more extensive treatment.
Each year, more than half a million people visit the emergency room for kidney-stone related problems. If you or your family have a history of kidney stones, it is important to know the factors that can increase the likelihood of developing the stones as well as different strategies to prevent them.