Kidney stones may be small, but if you’ve had them, you know they can be a big pain – to your back and other areas. It’s probably no consolation to know that many people have shared in your pain. The National Kidney Foundation estimates that more than half a million Americans visit emergency rooms each year for kidney stone problems, and that one in ten people will have a kidney stone at some point in their life. From causes to prevention, there are a lot of myths and misunderstandings surrounding kidney stones. But according to Hannah Hong, MD, a urologist with The Christ Hospital Physicians – Urology, the facts are pretty well known.
What is a kidney stone?
A kidney stone is a small crystal that forms from chemical substances found in urine. In most cases, these crystal-forming substances are eliminated by the kidney, but when concentrations are too high, they can crystalize and form stones.
There are four types of kidney stones:
Calcium based stones: usually caused by high levels of calcium in the urine combined with either high levels of oxalate or phosphate.
Uric acid stones: often caused by excessive levels of purines (by-products of animal protein) combined with acidic urine.
Struvite stones: which form from urease-producing bacteria that cause urinary tract infections.
Cystine stones: which are usually due to an inherited condition called cystinuria.
According to Dr. Hong, calcium oxalate stones are by far the most common and people are typically more aware of the risk factors and symptoms associated with that type of stone.
Some kidney stones are created and passed without issue, but when they move into the ureter, they can become lodged and block the flow of urine. This can cause swelling and spasms in the kidney and urinary tract and bring on the commonly known symptoms:
Acute pain on the side or back near the ribs
Radiating pain that moves into the groin, which can cause severe testicular pain in men
Irritative urinary symptoms such as increased urinary frequency or urgency
Nausea or vomiting
Fever and chills
Kidney stones can range in size from one millimeter or more. But according to Dr. Hong, stones larger than 5 millimeters are more likely to become lodged and cause pain. “Though even stones as small as one millimeter are capable of causing severe pain if they become lodged,” she says.
Many kidney stones eventually pass on their own without issues beyond pain, but Dr. Hong warns that any blockage and backup can come with an increased risk of infection to not only the bladder, but also the kidneys, so people who are trying to pass a kidney stone should watch closely for symptoms such as worsening fever, chills, nausea, and vomiting. In those cases, they should either call their urologist immediately, or if they don’t have one, go to the emergency room.
“If you have a urinary tract infection in addition to an obstructing stone, that’s a urologic emergency. We will need to perform a procedure immediately to unblock the obstructed kidney with a stent and arrange for stone removal when the infection has been cleared.”
How are kidney stones diagnosed?
The best and most accurate way to diagnose a kidney stone is with a CT scan without contrast, according to Dr. Hong. But she points out that providers may start the work-up with a renal ultrasound or an X-ray.
“Of course,” Dr. Hong says, “if somebody comes to the emergency department with severe pain and symptoms, we don’t want to delay treatment, so in those cases, we may go straight to the CT scan.” She also adds that X-rays only show calcium-based stones and both X-rays and ultrasounds can show stones in the kidney but are not as effective at finding them in the ureter, which is often surrounded by more tissue and organs.
Treatment of kidney stones
The preferred treatment for kidney stones is to let it pass naturally through the urine. Doctors recommend drinking a lot of water to promote urination, and they might actually prescribe medication to relax the ureter lining to help it move through. “These are the same medications often prescribed long-term to BPH patients to help relax enlarged prostates, but they can also offer short-term assistance with passing kidney stones,” Dr. Hong says.
Passage of a kidney stone can be quick, but it can also take four or more weeks, according to Dr. Hong, and doctors can prescribe pain medication to provide relief during the process, dependent on the severity of the pain. Patients are also often provided a strainer to collect the stone.
“That allows us to be one hundred percent sure that it’s passed,” Dr. Hong says. “Plus, we can analyze the stone to determine what kind it is, and work with the patient on dietary adjustments to reduce the risk of further episodes. Or in some cases, it can allow us to identify other factors such as genetic mutations that might make you more prone to kidney stones.”
Doctors may also urge other treatment options based on factors such as timing, the patient’s pain threshold, the presence of an infection, a patient with only one kidney, or the patient’s medical history. Those options are:
Shockwave lithotripsy: During this non-invasive option, the provider uses ultrasound shockwaves to break apart the stones from outside the body to make it easier to pass the particles. While this is the least invasive and easiest option, Dr. Hong points out that it can still be painful, so as with the next two options, the patient is still placed under anesthesia.
Ureteroscopy: During this minimally invasive procedure, the provider inserts a scope through the urethra. The scope contains a camera that allows them to view the stone, and a laser used to break it up. At that point, the fragments can either flow out naturally, or be removed with a surgical instrument. “The biggest benefit of this procedure over the shockwaves is the direct visualization with a camera allows us to be sure that all stones are removed,” Dr. Hong says.
Percutaneous nephrolithotomy (PCNL): During this surgical procedure, a tube is inserted directly into the kidney through a tiny incision in the back. An ultrasonic probe is used to break the stone apart and suction it out through the incision. This option is reserved for extreme cases such as those when the stone is too large to pass on its own or be broken up via other options.
Reducing the risk and separating fact from fiction
It’s a fact that many kidney stones, especially calcium oxalate stones, are caused by an imbalance of the materials that combine to form the stones and the amount of calcium and fluid necessary to dispose of them. That’s why experts agree that they best prevention method for kidney stones is proper hydration.
“We recommend producing at least 2.5 liters of urine per day,” Dr. Hong says. “That means you have to drink much more than that amount. We suggest at least 12 cups of fluid. Water is best, but other fluids still help, as long as they are not high in sodium or sugar. Those liquids are actually counter-productive.”
Speaking of sodium and sugar, Dr. Hong points out that excessive intake of both greatly increase the risk of forming calcium oxalate stones. “Typically, processed and restaurant foods are much higher in sodium, so we tell our patients with a history of stones to limit those foods and to eat healthier, home-cooked meals. Unprocessed fruits and vegetables and whole grains are also useful for maintaining a balance that reduces the risk.
Dr. Hong points out that one of the biggest myths surrounding kidney stones is that it helps to limit food and drink such as dairy products that are high in calcium.
“I know it sounds counter-intuitive, but a healthy amount of calcium intake, especially through natural consumption versus supplements, actually helps reduce the risk of calcium oxalate stones forming,” she says. “We recommend 1,200 milligrams of calcium a day.”
She points out that everything we eat has oxalates, and those are attracted to calcium. Having a healthy amount of calcium in your gut allows the oxalates to bind to that calcium in the gut where it can be processed before it reaches the kidneys where it is more likely to crystalize when it binds to calcium.
Another myth that Dr. Hong points out is the use of cranberry juice to reduce the risk of kidney stones. Citrates can be useful in protecting against the formation of stones and she hears from patients who drink a lot of cranberry juice because it is high in citrates.
“The problem with cranberry juice is that while it has a lot of citrates, it also generally contains enough sugar to actually increase the risk, rather than reduce it,” Dr. Hong says. “We recommend getting citrates through other means such as eating fruits like grapefruits and oranges or putting a little bit of lemon juice in your water.”
Certain foods that are otherwise healthy also contain a lot of oxalates and can increase the risk of kidney stones. These include foods such as spinach, potatoes and certain nuts and seeds. Dr. Hong says she doesn’t suggest that most people concern themselves with eating such foods due to their otherwise healthy benefits, but that patients with a history of kidney stones should be aware of how much they are eating and be sure to not overdo it.
She also warns against excessive intake of supplements containing minerals that are important to your health such as Vitamin D and Vitamin C, as excessive intake can promote the formation of kidney stones. “You need those vitamins, and you should be sure you are getting enough,” she says. “But it’s best to do it naturally versus supplements that provide excessive amounts beyond what is even useful to the body.”
Animal protein can also increase the risk of certain kidney stone formation. “You need protein,” Dr. Hong says, “but the recommended maximum is one gram per kilo of bodyweight a day, so for most people if you’re taking in as much as 80-100 grams of animal protein, that’s probably more than you need. Like with other items, it’s best to stay aware of what you are taking in, especially if you have a history of kidney stones.”
Dr. Hong also recommends regular care from a urologist if you have a personal or family history of kidney stones. “We can do more than offer treatment and relief,” she says. “Your urologist can analyze stones when they occur to help you determine exact causes and to help you establish lifestyle and dietary changes to reduce your risk. We can also help to identify underlying metabolic or genetic issues that could be indicative of other health concerns. The benefits go beyond treatment and relief.”
To schedule with a urology expert with The Christ Hospital Health Network, call 513-721-7373, or click here to find an expert.