Kidney stones are common, affecting approximately 1 in 5 men and 1 in 10 women by the time they reach 70 years of age. These deposits form in the kidney when salts and minerals that are normally in the urine build up and harden.
Certain dietary habits, medications, and certain diseases have been associated with increased risk of kidney stones.
Dietary habits that increase odds of kidney stones:
Not drinking enough fluid. Those prone to making kidney stones should drink at least 2 liters of fluids per day.
Diet with low levels of calcium
Use of calcium supplements
Diet with high levels of animal protein
Diet with high levels of sugars (sucrose, fructose)
Diet with low levels of phytate (found in wheat, rice, rye, barley, and bean products)
High sodium diet
Frequent spinach consumption
Medications that increase odds of kidney stones:
Vitamin C supplements
Certain water pills (diuretics)
Anti-seizure medications such as phenytoin
Medical conditions associated with kidney stones:
Gastric or intestinal bypass surgery
Sometimes, small stones do not cause any symptoms when they pass from the kidneys through the urinary tract. However, large kidney stones can cause a lot of distress. Symptom intensity varies and typically include:
Sharp, cramping pain in the back and side to the lower abdomen or groin
Pain that starts suddenly and comes in waves
Nausea and vomiting
A feeling of intense need to urinate
Burning during urination
Blood-tinged or red urine
The diagnosis is made based on symptoms, physical exam, and imaging studies. Imaging studies such as an ultrasound or a CT scan can reveal how big the stone is and where it is located.
Patients are often asked to urinate into a strainer to catch the stone for analysis. Understanding the composition of the stone can help determine the cause and direct a strategy to prevent future kidney stones.
Small stones with minimal symptoms and no signs of infection or blockage will most likely pass with adequate fluid intake. When managed at home, the doctor may recommend a pain-reliever and prescribe a medication (such as tamsulosin) to make it easier for the stone to pass.
Severe pain or nausea will need to be treated with stronger pain medications and intravenous fluids at the hospital.
Kidney stones that are larger than 9 or 10 millimeters rarely pass on their own and can cause bleeding, kidney damage, or urinary tract infection. These stones will require procedures to break up or remove the stones. The procedures include:
Ureteroscopy. This procedure uses a thin tube with a camera that allows the doctor to see and break up and remove the stone.
Shock wave lithotripsy. High energy shock waves that pass through the skin are used to break the stone into fragments so that they can be more easily passed.
Percutaneous nephrolithotomy. This minimally invasive surgery uses small telescopes and instruments inserted through a small incision in the back to remove the stone.
People who have had a kidney stone are likely to have another one in the future. Depending on the type of stone, certain lifestyle modifications can help decrease the risk of kidney stones.
Some of the preventative dietary measures include:
Drink at least 9 cups or 2 liters of fluids per day
Reduce salt intake
Reduce animal protein intake by eating less meat and more non-animal proteins such as legumes
Medications can be adjusted or prescribed by a doctor to reduce the risk of recurrence, depending on the type of stone.
Frassetto L, Kohlstadt I. Treatment and prevention of kidney stones: an update. Am Fam Physician. 2011 Dec 1;84(11):1234-42.
Khan SR, Pearle MS, Robertson WG, Gambaro G, Canales BK, Doizi S, Traxer O, Tiselius HG. Kidney stones. Nat Rev Dis Primers. 2016 Feb 25;2:16008.