Kidney Stones: Symptoms, Types, Causes and Treatment
Kidney stones (renal calculi, urolithiasis, or nephrolithiasis) are hard masses, deposits of minerals and salts that form inside the kidneys.
Kidney stones are usually the size of a chickpea, but they can also be as small as a grain of sand or as large as a golf ball. Small stones can pass through the urinary tract, but larger ones may require surgery.
Kidney stones can be caused by various factors, including diet, excess body weight, certain medical conditions, and certain supplements and medications. They can affect any part of the urinary tract, including the kidneys and bladder.
Kidney Stone Symptoms
A kidney stone usually does not cause symptoms until it moves around within the kidney or goes through the ureters, which connect the kidneys and bladder. It can block the flow of urine and cause the kidney to enlarge and the ureter to spasm, which can be quite painful. You may then experience the following signs and kidney stones symptoms:
As a kidney stone passes through the urinary tract, the pain it causes may vary—for example, it may migrate to a new spot or rise in intensity.
Types of Kidney Stones
Knowing the type of kidney stone can help determine its cause and may guide you on how to lower your risk of future kidney stones. If possible, save the kidney stone and bring it to the doctor for analysis.
- Calcium stones: The majority of kidney stones are calcium stones, most of which are calcium oxalate. Oxalate is a chemical that the liver produces or that people consume through their diet. Oxalate levels are high in several fruits and vegetables, as well as nuts and chocolate.
- Struvite stones: These develop as a result of a urinary tract infection. They can grow rapidly and become quite large, with minimal signs or warnings.
- Uric acid stones: People who consume high-protein diets, have diabetes or metabolic syndrome, and lose too much fluid due to chronic diarrhea or malabsorption are at risk of developing uric acid stones. Certain genetic factors may also enhance one's chances of developing uric acid stones.
- Cystine stones: These stones are formed in people who have cystinuria, a hereditary condition in which the kidneys discharge an excessive amount of specific amino acids.
What Causes Kidney Stones?
There is no known cause of kidney stones. However, certain conditions may increase the chances of developing this disorder.
- Dehydration: Inadequate fluid intake can lead to concentrated urine, promoting the formation of kidney stones as minerals become more focused and crystallize.
- Dietary Factors: Consuming a diet high in sodium, oxalate, and animal proteins, while low in calcium and fluids, can increase the risk of kidney stone formation by promoting the accumulation of minerals in the urine.
- Family History: A family history of kidney stones increases the likelihood of developing them, suggesting a genetic predisposition to stone formation or shared environmental factors.
- Medical Conditions: Certain medical conditions such as urinary tract infections, cystic kidney diseases, hyperparathyroidism, and inflammatory bowel diseases can alter urine composition or kidney function, predisposing individuals to kidney stone formation.
- Obesity: Excess weight and obesity are associated with metabolic changes that can increase urinary excretion of calcium, uric acid, and other substances that contribute to kidney stone formation.
Risk factors
Factors that increase the risk of developing kidney stones include:
- Dehydration: Not drinking enough water can raise the risk of kidney stones. People who live in hot, dry regions or who sweat a lot may be at a higher risk than others.
- Obesity: A high BMI, a large waist circumference, and weight gain have all been associated with an increased risk of kidney stones.
- Digestive diseases and surgery: Changes in the digestive process caused by inflammatory bowel disease or gastric bypass surgery might impair calcium and water absorption, increasing the amount of stone-forming chemicals in the urine.
How are Kidney Stones diagnosed?
- Blood testing: Blood tests may identify an excess of calcium or uric acid in your blood. The results help your doctor monitor the health of your kidneys and may lead him or her to examine you for other medical concerns.
- Urine testing: In this test, urine is collected 24 hours a day. This could indicate that the individual is excreting either too many stone-forming minerals or not enough stone-preventing chemicals. The doctor may recommend collecting two urine samples on two consecutive days for this test.
- Imaging: Urine imaging tests may reveal kidney stones. Even microscopic stones can be detected using high-speed or dual-energy computerized tomography (CT). Simple abdominal X-rays are less commonly utilized. Another imaging technique for diagnosing kidney stones is ultrasound, which is a non-invasive, rapid and easy test.
Kidney Stones Treatment
Small stones with minimal symptoms Most small kidney stones do not require invasive treatment. The small stone can be passed through:
- Drinking water: Drinking 1.8 to 3.6 litres of water per day will dilute the urine and may prevent stones from developing. Unless otherwise directed by the doctor, drink enough water to create clear or almost clear urine.
- Using sound waves to break up stones: The doctor may recommend extracorporeal shock wave lithotripsy (ESWL) for specific kidney stones. Sound waves are used in ESWL to generate intense vibrations (shock waves) that break the stones into little pieces that can be passed in your urine. The operation takes about 45 to 60 minutes and can be painful, so patients may be medicated or given light anaesthesia to make them more comfortable.
- Surgery to remove huge stones in the kidney: Percutaneous nephrolithotomy is a kidney stone surgery that removes the kidney stone using a small telescope that is placed through a small incision in the back. During the procedure, patients will be anaesthetized and hospitalized for one to two days to recover. If ESWL does not work, the doctor may recommend this surgery.
- Using a scope to remove stones: To remove a small stone in the ureter or kidney, the doctor may insert a thin tube, known as a ureteroscope, equipped with a camera through the urethra and bladder into the ureter. Once the stone has been identified, specific equipment can entrap it or break it up into pieces that will flow through the urine. The doctor may then insert a small tube (stent) into the ureter to reduce swelling and facilitate recovery. This operation may require a general or local anaesthetic.
How To Prevent Kidney Stones?
- Stay Hydrated: Drink plenty of water throughout the day to maintain adequate urine volume and prevent mineral concentration.
- Follow a Balanced Diet: Adopt a diet rich in fruits, vegetables, and whole grains while limiting sodium, animal proteins, and oxalate-rich foods.
- Monitor Calcium Intake: Ensure adequate but not excessive calcium intake from dietary sources to prevent calcium oxalate stone formation.
- Limit Oxalate-Rich Foods: Reduce consumption of oxalate-rich foods like spinach, nuts, and chocolate to lower the risk of calcium oxalate stone formation.
- Maintain a Healthy Weight: Achieve and maintain a healthy weight through a balanced diet and regular physical activity to reduce the likelihood of kidney stone formation.
