Kidney stones are common. Some types run in families. They often occur in premature infants.
There are different types of kidney stones. The cause of the problem depends on the type of stone.
Stones can form when urine contains too much of certain substances that form crystals. These crystals can develop into stones over weeks or months.
- Calcium stones are most common. They are most likely to occur in men between ages 20 to 30. Calcium can combine with other substances to form the stone.
- Oxalate is the most common of these. Oxalate is present in certain foods such as spinach. It is also found in vitamin C supplements. Diseases of the small intestine increase your risk of these stones.
Calcium stones can also form from combining with phosphate or carbonate.
Other types of stones include:
- Cystine stones can form in people who have cystinuria. This disorder runs in families. It affects both men and women.
- Struvite stones are mostly found in women who have a urinary tract infection. These stones can grow very large and can block the kidney, ureter, or bladder.
- Uric acid stones are more common in men than in women. They can occur with gout or chemotherapy.
- Other substances such as certain medicines also can form stones.
The biggest risk factor for kidney stones is not drinking enough fluids. Kidney stones are more likely to occur if you make less than 1 liter (32 ounces) of urine a day.
Symptoms of Kidney Stones
You may not have symptoms until the stones move down the tubes (ureters) through which urine empties into your bladder. When this happens, the stones can block the flow of urine out of the kidneys.
The main symptom is severe pain that starts and stops suddenly:
- Pain may be felt in the belly area or side of the back.
- Pain may move to groin area (groin pain) or testicles (testicle pain).
Other symptoms can include:
- Abnormal urine color
- Blood in the urine
- Nausea and vomiting
Kidney Stone Diagnosis
Your health care provider will perform a physical exam. The belly area (abdomen) or back might feel sore.
Tests that may be done include:
- Blood tests to check calcium, phosphorus, uric acid, and electrolyte levels
- Kidney function tests
- Urinalysis to see crystals and look for red blood cells in urine
- Examination of the stone to determine the type
Kidney Stone Treatment
Treatment depends on the type of stone and the severity of your symptoms.
Kidney stones that are small most often pass through your system on their own.
- Your urine should be strained so the stone can be saved and tested.
- Drink at least 6 to 8 glasses of water per day to produce a large amount of urine. This will help the stone pass.
- Pain can be very bad. Over-the-counter pain medicines (for example, ibuprofen and naproxen), either alone or along with narcotics, can be very effective.
Some people with severe pain from kidney stones need to stay in the hospital. You may need to get fluids through a vein.
For some types of stones, your provider may prescribe medicine to prevent stones from forming or help break down and remove the material that is causing the stone.
Surgery is often needed if:
- The stone is too large to pass on its own
- The stone is growing
- The stone is blocking urine flow and causing an infection or kidney damage
- The pain cannot be controlled
Minimally Invasive Treatments
Today, most treatments are much less invasive than in the past. Our physicians are experts in all treatment options, including minimally invasive procedures that are popular because of the potential for shorter hospital stays and quicker recovery times. For example,
- We offer laparoscopy for a variety of conditions.
- We are one of a few centers in the country offering robotic-assisted laparoscopic procedures for both children and adults. Our minimally invasive surgery team is headed by a world expert who helped establish robotic surgery in the field of urology and traveled the globe initiating urologic robotic surgery programs.
With robotic surgery, surgeons make small incisions in the patient’s abdomen through which a camera and robotic instruments are inserted. The surgeon sits at a console away from the patient and controls four instruments using finger and hand movements. The tiny centimeter-sized instruments eliminate the need for the six- to eight-inch incision required with traditional surgery. The camera gives the surgeon a three-dimensional view inside the patient’s body with a magnification of 10- to 15-fold.
Minimally invasive options for kidney stones include:
Shock wave lithotripsy – An energy source directs a shock wave at the stone, causing it to fragment into small pieces. Shock waves reach the patient through a water bath.
Ureteroscopy – The surgeon uses a small, fiber-optic instrument to gain access to the kidney or ureter. Instruments are used to remove the stone, or if it is too large, to shatter it first.
Percutaneous Nephrolithotomy – Used for large stones located in the kidney. It requires only a small incision in the flank.
Dietary Information for Kidney Stone Prevention
Diet is a key environmental factor which can be modified to reduce stone formation. A simple dietary approach which is beneficial for the majority of kidney stone patients is reviewed in this handout.
Urine needs to be supersaturated with the chemicals that compose the stones for them to develop. This means that there is a high concentration of these chemicals present. When this occurs, the respective chemicals crystallize, clump together (aggregate) and a stone eventually develops. This can be due to excessive excretion of these chemicals in urine and/or dehydration. This is a simplified description of this process which is actually quite complex and modulated by a number of other factors.
Consuming an adequate amount of fluid is a simple and safe method of decreasing urinary super saturation. Tap water is an excellent and readily available fluid for this purpose. However, other fluids may be utilized. Citrus juices and some mineral water preparations contain citric acid which is a chemical that inhibits the crystallization of stone-forming chemicals.
The goal for adult patients is to consume enough fluid for a daily urine output of 2 to 3 liters. Drinking 8 - 10 ounces of water per hour while awake will usually allow this to occur. Another index of adequate hydration is that urine should be almost as light as water.
The consumption of large amounts of animal protein produces a number of changes in the urinary environment which may promote stone formation including lower pH, increased excretion of calcium, oxalate and uric acid, and reduced excretion of citrate. Therefore, limiting consumption of animal protein, especially red meat, is advisable. The Atkin's diet should be avoided as it is based on high protein intake which will promote all of the aforementioned urinary changes. A daily protein intake of 1 gram per kilogram of body weight (1 kilogram = 2.2 pounds) is recommended.
High salt consumption should be avoided as it promotes a number of deleterious urinary changes for stone patients including an increase in urinary calcium and cystine excretion, and a reduction in citrate excretion. Sodium intake should be limited to 2 grams per day for adults.
The majority of kidney stones are composed of calcium, and a combination of oxalate or phosphate or both. Dietary calcium restriction was recommended for a number of years. However, there is now ample evidence that this should not be undertaken. Most adults should eat enough dairy products or other calcium containing foods which in total provides 1 to 1.2 grams of calcium per day. An effort should be made to equally distribute calcium intake throughout daily meals.
High-Oxalate Containing Foods
Calcium oxalate stone-formers should avoid eating foods containing high amounts of oxalate. Examples of such foods include spinach, parsley, rhubarb, cranberries, celery, peanuts, soy products, fiber containing cereals, bran and chocolate.
Stone patients should avoid consuming excessive amounts of Vitamin C (ascorbate/ascorbic acid). The amount of Vitamin C present in the standard multi-vitamin tablet it not excessive and thus these can be taken. However, other preparations containing greater amounts of this vitamin should not be taken as this may increase urinary oxalate excretion. Calcium supplements such as Tums and Citracal may promote increased calcium excretion when consumed. Thus, one should let their urologist know if they are taking such preparations so that specimen urine testing can be done to determine whether continued utilization is advisable.