Kidney stones are hard, pebble-like deposits that form inside your kidneys when high levels of certain minerals and salts are present in your urine. They can vary in size, from a grain of sand to a golf ball. This common condition typically does not cause permanent damage if managed appropriately.
Causes and Risk Factors
Kidney stones often begin to form when there is an imbalance in substances dissolved in urine, leading to crystals. A primary cause is insufficient fluid intake, which results in concentrated urine where minerals like calcium, oxalate, and phosphorus crystallize. Dehydration, especially from heavy exercise or hot climates, lowers urine production, allowing these stone-forming minerals to settle.
Dietary habits also play a substantial role. Diets high in sodium can increase calcium excretion in urine, promoting stone development. High intake of refined sugars can contribute to the risk. A diet rich in animal proteins can raise acid levels in the body and urine, increasing the likelihood of uric acid and calcium oxalate stones.
Certain medical conditions and personal history can increase susceptibility. Urinary tract infections (UTIs) are a known cause for struvite stones, while hyperparathyroidism can lead to elevated calcium levels in blood and urine. Digestive diseases, like Crohn’s disease, ulcerative colitis, or gastric bypass surgery, can alter how the body absorbs water and calcium, potentially increasing oxalate levels in urine. A family history of kidney stones or previous stones also raises the risk of developing more.
Recognizing the Symptoms
Kidney stone symptoms often become noticeable when a stone moves within the kidney or enters a ureter. The most prominent symptom is intense, sharp pain in the side and back, typically below the ribs. This pain can be described as colicky, meaning it comes in waves and fluctuates in intensity, often radiating to the lower abdomen and groin. Men may also experience pain in their testicles.
Individuals might experience a burning sensation during urination. Changes in urine appearance are also frequent, including pink, red, or brown due to blood (hematuria), or cloudy/foul-smelling urine. Increased urinary urgency and frequency are also reported.
Nausea and vomiting are common due to the intensity of the pain. If an infection is present, fever and chills can occur. The size of a kidney stone does not always correspond to the severity of pain; even small stones can cause extreme discomfort as they pass.
Medical Diagnosis and Treatment Options
When symptoms suggesting kidney stones arise, medical professionals use diagnostic methods to confirm and characterize them. A thorough medical history and physical exam are followed by laboratory tests, like urine and blood tests, to check for high levels of stone-forming minerals or signs of infection. Imaging tests are then conducted to pinpoint the stone’s size, location, and whether it is causing a blockage. CT scans are the standard for diagnosis, while ultrasounds are often used, especially for pregnant women or children.
Treatment approaches vary based on the stone’s size, type, and location. For smaller stones likely to pass on their own, home management is often recommended. This involves plenty of fluids to flush the stone, and pain relievers like NSAIDs. In some cases, an alpha-blocker medication, such as tamsulosin, can be prescribed to help relax the ureter muscles, making it easier for the stone to pass.
When stones are larger or do not pass naturally, more direct interventions become necessary.
Extracorporeal Shock Wave Lithotripsy (ESWL)
This non-invasive procedure uses high-energy sound waves to break the stone into smaller fragments. These smaller pieces can then be passed more easily through the urinary tract.
Ureteroscopy
This involves inserting a thin, lighted ureteroscope through the urethra and bladder, up into the ureter or kidney. Once the stone is located, it can either be removed with a basket or broken into smaller pieces using a laser.
Percutaneous Nephrolithotomy (PCNL)
For very large or complex stones, PCNL is often used. This surgical procedure involves making a small incision in the back to directly access the kidney and remove the stone, or break it up with a laser. These procedures are performed under anesthesia, with PCNL typically requiring a short hospital stay.
Lifestyle and Dietary Prevention
Preventing kidney stones largely centers on lifestyle and dietary adjustments. A primary preventative measure is consistently adequate hydration. Drinking enough water, aiming for 2-3 liters (8-12 cups) daily, helps dilute the concentration of stone-forming minerals in urine, making it less likely for crystals to form. Monitoring urine color, aiming for clear or light yellow, indicates proper hydration. Increase fluid intake during hot weather or intense physical activity to compensate for fluid loss through sweat.
Dietary modifications are also beneficial. Reducing sodium intake is important, as high levels can increase calcium excretion in urine, contributing to calcium-based stones. Limiting daily sodium to less than 2,300 milligrams is recommended, by avoiding processed and prepackaged foods.
Maintaining a balanced calcium intake is protective against stone formation. Adequate dietary calcium, 1,000-1,200 milligrams daily, helps calcium bind with oxalate in the gut, reducing the amount absorbed and excreted by the kidneys. However, calcium supplements taken without meals can increase stone risk by raising urinary calcium without the beneficial oxalate binding effect.
Limiting animal protein intake can also help prevent stones, particularly uric acid stones, as high consumption can increase uric acid levels and decrease citrate in urine, both factors that promote stone formation. Moderating portions can be beneficial.
For those prone to calcium oxalate stones, being mindful of oxalate-rich foods like spinach, rhubarb, almonds, and beets can be helpful. Pairing these foods with calcium-rich foods can help bind oxalate in the digestive tract, preventing it from reaching the kidneys.