If you’ve ever had a kidney stone, you know how extraordinary the pain can be. Many patients have told me this is the worst pain they have ever experienced.
Let’s start by talking about what kidney stones are. Your kidneys filter blood, and in doing so, they remove waste and excess water and minerals. These materials are carried out of the body as urine. If an imbalance of minerals occurs or dehydration is present, kidney stones can result.
Risk Factors for Kidney Stones
Risk factors are things that make you more likely to develop kidney stones. For instance, people who don’t drink enough water are at higher risk of getting kidney stones. Assess your own risk factors by answering “yes” or “no” to the questions below. The more times you answer “yes,” the higher your chances of forming kidney stones.
- Do you drink fewer than eight glasses of water a day?
- Have you had a kidney stone before?
- Has anyone in your family had kidney stones?
- Are you between the ages of 30 and 50?
- Do you live in a hot climate?
- Do you have frequent urinary tract infections?
- Do you have a history of gout or bowel disease?
- Is your diet high in sodium (salt) or animal protein?
- Do you often have cola, black tea, chocolate, spinach, or nuts?
- Are you overweight?
Symptoms & Diagnosis of Kidney Stones
Some patients never have symptoms of kidney stones and they are only picked up when imaging is done for some other reason. However, some classic symptoms for kidney stones include:
• Mild to severe pain, which typically starts in the mid-back or side (under the ribs) but can move to the front and down to the groin.
• Nausea and vomiting
• More frequent urination
• Fever- this is an emergency!
• Blood in the urine
Patients often come to the emergency room in tremendous pain and are examined for the cause. If a kidney stone is suspected, a CT scan is often obtain to determine that a kidney stone is the cause, and also the type, size and location of the kidney stone.
How Kidney Stones are Treated
In many cases, the treatment for kidney stones is to pass them, and to manage pain and other symptoms during the process. (Sometimes procedures are surgeries are needed, which I detail later in this article.)
The passage of a stone depends on location (upper, middle or lower ureter
, which is the tube that goes between the kidneys and the bladder), stone size, and any previous stone history.
The higher the stone when it gets “stuck,” the lower the chance of passing it. This is often when we see people showing up in the emergency department in terrible pain.
Kidney stones can be various sizes. Those that are 3mm and smaller have about an 85% of passing on their own. Stones 4mm have about a 50% chance, and stones 5mm and above have about a 30-40% chance of a person passing it successfully.
Those who may have passed stones in the past are usually able to pass larger stones in the future.
Passing a kidney stone
There are ways we can assist in the passing of a stone. This is called “medical expulsive therapy.” This means:
1) Controlling the pain and nausea with pain medication and anti-vomiting medication. We prefer to use nonnarcotic pain medications when possible as narcotic (opioid) pain medications carry their own risks of lung and GI problems as well as long-term dependence.
2) Medications to help the ureter relax so that the stone can pass through more easily. Currently, we use a drug called Flomax.
3) Stones made of uric acid (which occurs in about 10% of stones); we can sometimes help dissolve those with medication to make the urine less acidic.
4) Straining your urine with a urine strainer to catch any stones that pass. These can be analyzed to help prevent future stones.
5) Fluids, fluids, fluids! Anything you can keep down to increase the amount of urine you produce will improve your chances of passing the stone.
6) Regular follow-up with abdominal x-ray to determine if the stone is moving down or has passed.
If you are in the process of passing a kidney stone, contact your doctor OR go to the emergency room if you have the following symptoms, as they can be signs of an emergency that would require immediate medical care:
• Severe pain or nausea and vomiting that doesn’t respond to the oral medications.
• Development of fever above 101 degrees, and chills.
• Inability to urinate, more in men than women.
Procedures & Surgery for Kidney Stones
Sometimes stones don’t pass on their own, and often waiting for the stone to pass isn’t the best option, due to the location or size of the stone, or if infection is present. Stones greater than 1 cm in size rarely pass on their own and generally require a procedure or surgery. If that is the case, there are three primary procedures, which I’ll detail below.
Shock Wave Lithotripsy (SWL)
SWL is a common procedure used to treat kidney stones. SWL is not for every stone. It is typically used for stones in the kidney and upper ureter (the tube that connects the kidney and bladder). The procedure uses shock waves to break the stones into small pieces without making any cuts or putting anything inside of you.
During SWL, a machine generates shock waves that are transmitted into the kidney stone through a sensor outside your body. The waves are focused on the kidney stone, so there is little impact to the skin and nearby tissues. The stone is broken up into small, sandlike pieces, which can then pass easily out of the body in urine. X-rays are taken before and during the procedure to localize the stone and make sure it’s broken up.
During SWL, general anesthesia is most often used, and you’ll likely go home the same day. A few days later, you may have an x-ray to make sure that the stone is completely broken up and out of your body.
There are some risks with SWL, including the need for a repeat procedure, infection and bleeding. Overall, SWL is the least invasive procedure, but does have the highest chance of needing a follow-up operation to remove the stone.
A ureteroscope is small telescope with a camera on it that is inserted through the urethra and bladder and into the ureter. Sometimes the stone can just be removed with a basket without fragmentation. Other times a laser fiber is sent through the scope to break up the stone. The stone fragments can then pass in the urine.
Some differences in URS and SWL are:
- URS is more invasive
- URS usually requires a stent (hollow plastic tube) to drain the ureter. SWL most often does not require a stent. Stents can often cause symptoms of their own- frequent urination, blood in the urine and even pain similar to a kidney stone. This stent is important to allow the ureter to heal after having a telescope and stone inside of it.
- Stone-free rates are better with URS than SWL. That means that URS is more likely to remove all stones and stone fragments at once than SWL, and you are less likely to need a different procedure.
- Since URS employs a very powerful laser, harder stones respond much better than to SWL.
- URS is also done under general anesthesia, and you’ll likely go home the same day. A few weeks or months later, imaging tests may be done. These check if all stones were removed.
Bleeding, infection and possible injury to the ureter are possible risks, but are uncommon.
Percutaneous nephrolithotomy (PCNL)
PCNL is typically used for larger stones located in the kidney. This is the most invasive treatment and is used for very large stones. A small incision is made in the back, about the size of a quarter, and a telescope with a camera is inserted through the incision directly into the kidney. Lasers or other devices passed through the scope break up the stone, and the stone fragments are then sucked back out through the scope.
For this procedure, you’ll be hospitalized overnight afterwards, and you may have a tube in your kidney afterwards or a stent inside of you. These are temporary.
Advantages of PCNL are:
- Best way to treat large stones. Current recommendations are for PCNL to treat any stone larger than 1.5 cm. (about 2/3 of an inch—or the size of a nickel)
- It has the best result for leaving the kidney without stone fragments, and “washes out” any remaining particles. This means it has the highest “stone free” rate for bigger stones.
- This procedure relieves the burden of the patient trying to pass any remaining fragments, because they’re removed during the procedure. They’re literally crushed and sucked out through the scope.
- Areas that may not be reachable with other methods are sometimes best accessed via PCNL.
As with any surgical procedure, because it is more invasive, there is a slightly higher risk for infection and bleeding than with URS and SWL. There may be minor loss of kidney function, but serious complications are uncommon. However, because it is more invasive it is not for every patient. Older or sicker patients with other medical problems may not be candidates for PCNL.
Preventing Future Stones
Once you’ve had a kidney stone, you’re more likely to have another stone in the future. But you can take steps to prevent kidney stones.
Hydration. This is the most important step.
Drink lots of fluids. Staying hydrated helps flush minerals out of your kidneys before they can build up and cause stones. Aim to drink about eight 12 ounce glasses of fluid each day. Water is best. These tips can also help:
- Drink a glass of water at each meal.
- Drink a glass of water when you brush your teeth, right before bed, to keep you well hydrated throughout the night.
- Keep a bottle of water with you throughout the day, and take sips whenever you can.
- Limit alcohol and caffeine because these work as diuretics and tend to dehydrate.
- Check the color of your urine to see if you’re drinking enough. Clear or light yellow urine is good, and dark yellow urine means you need to drink more. Dark urine is more concentrated, which promotes the formation of stones. Your goal is to make 2 liters of urine every day.
Drinking lemonade can be VERY helpful in preventing stones. The citrates in lemonade are natural inhibitors of stone formation in the kidneys. Other options to add Citrate include adding natural lemons or lemon juice to water, lemon extract, Crystal Light and Sprite Zero.
Limit your intake of sodium, especially from processed, canned and frozen foods. Sodium often seems “hidden,” and we consume much more than just what we “shake on” at the table.
High-Oxalate Food and Drinks
Avoid high-oxalate foods and drinks, such as chocolate, nuts, black tea and colas. 90% of all stones are calcium-oxalate stones.
Consume the recommended daily amount of calcium in your diet. Too little calcium in your diet can lead to kidney stones because your body wants to replace the natural turnover of calcium. If you don’t have enough calcium in your diet, it’s leached from your bones and is more likely to cause kidney stones.
Lose any excess weight. Your doctor can help you create a weight loss plan.
Going forward, the best way to lower your risk of developing future kidney stones is to work with your doctor. This means following your treatment plan. Your doctor (urologist) may also suggest further testing and preventive medications.
Further testing can help determine why you formed kidney stones. This information can be used to help prevent stones. Tests can include stone analysis, 24-hour urine samples and blood tests.
Preventive medications can be prescribed to help prevent the formation of new stones. These include medications that reduce the amount of calcium excreted in the urine, reduce the amount of uric acid excreted in the urine, prevent certain types of stones, and dissolve uric acid stones.
After treatment for a kidney stone, it’s up to you to make lifestyle changes to help keep new stones from forming. Follow your doctor’s instructions, drink lots of fluids, and eat right. These simple steps can help you live free of kidney stone pain.
Krames patient education material content also contributed to this article.