What Are Kidney Stones


What Are Kidney Stones?

Most of us have heard the term “kidney stones,” but do we understand what they are, what causes them and how best to prevent them? Read along to learn more. 

Kidney stones are caused when a buildup of dissolved minerals collect in the inner lining of your kidneys. There are several types, but the most common is composed of calcium oxalate. Typically, stones are small and can even pass through the urinary tract unnoticed, however, they can grow very large and maintain a crystalline or sharp structure causing much discomfort.

To understand more about kidney stones, let’s start with kidney basics.

Your kidneys are fist-sized organs located at the lowest part of your rib cage, on each side of your spine. They are one part of the urinary tract and are primarily known for their function as filter organs, removing waste from the body. But they also are responsible for several other functions, including releasing hormones that help regulate blood pressure, balances the body’s fluids, help to control the production of red blood cells and more.

Your kidneys make urine using water and your body’s waste. From there, urine travels down tubes called ureters to the bladder.

What are Stones?

There are several different types of stones, which dictate how they are treated and how best to prevent them.

Calcium Stones – This type makes up about 80% of all kidney stones and has two subcategories: calcium oxalate and calcium phosphate. Calcium stones form most often where there is too much calcium in the urine, however, they can also form under other conditions.

Uric Acid Stones – This type of stone makes up about 5-10% of all kidneys stones. Uric acid is a waste product that results from chemical changes within the body. These crystals formed from uric acid do not typically dissolve well in acidic urine and can form a uric acid stone. There are a few conditions that can increase your risk of having acidic urine. These include gout, type 2 diabetes, being overweight and a diet high in animal protein and low in vegetables and fruits.

Struvite Stones – This type, also known as infection stones, accounts for about 10% of kidney stones. They are related to chronic urinary tract infections (UTIs.) When urine becomes alkaline, or less acidic, from certain types of bacteria, this type of stone can form. They are typically fast-growing stones and often are large with branches.

Cystine Stones – This is a rare type of stone, accounting for only about 1% of all kidney stones. Cystine is an amino acid, a building block of protein, found in some foods. Some people have a rare, inherited disorder called cystinuria which causes the kidneys to not reabsorb the cysteine from the urine. This concentration of cystine leads to stones forming. These stones typically begin in childhood.

What Are the Symptoms of Kidney Stones?

Generally, when stones are forming in the kidneys there are little to no symptoms. Once a stone leaves the kidney, it travels through the ureter to the bladder. Often, the stone can then become lodged within the ureter and can block the flow of urine out of the kidney. In turn, this can lead to swelling within the kidney and cause pain.

The most common symptoms of kidney stones include:

  • Sharp, cramping pain in the back and side. It often starts suddenly, comes in waves and can move to the lower abdomen or groin.
  • Intense feeling of needing to urinate.
  • Increase in frequency of urination and burning sensation when urinating.
  • Blood in urine.
  • Nausea and vomiting.
  • For men, pain may be felt at the tip of the penis.

What Causes Kidney Stones?

Dehydration – Low urine volume, often presents with dark urine, which means that the urine is concentrated. This means that there is not enough urine to dissolve the salts and minerals in your body. It is recommended that adults consume about 3 liters of fluid a day, on average. More may be required if you are living or working in a hot place, exercising or based on other medical conditions.

Diet – While calcium stones are caused by high levels of calcium in the urine, doctors will rarely request a patient to reduce their calcium intake. This is typically not caused by the amount of calcium you consume, but rather the way your body handles the calcium. In addition, calcium is vital for bone health and reducing overall calcium intake may actually increase the risk of kidney stones. Instead, your doctor may recommend reducing your salt intake. Too much salt makes it more difficult for the body to absorb excess calcium. And, as mentioned before, diets high in animal protein may also increase the risk of developing kidney stones because it can raise the acid levels in the urine. When the urine is acidic, it makes it easier for calcium oxalate and uric acid stones to form.

Obesity – Obesity raises risk factors for many medical conditions, including kidney stones. It chances the acid levels of the body and the urine, again, making it easier for stones to form.

Medications & Family History – There are a few medications that may increase your risk of developing kidney stones. In addition, speak to your doctor if you have a family history of kidney stones.

Bowel Medical Conditions – Conditions such as Crohn’s Disease or ulcerative colitis or surgeries, such as gastric bypass, may increase the chance of diarrhea. This may, in turn, result in the loss of large amounts of fluids in the body, lowering overall urine volume.

How are Kidney Stones Diagnosed?

There are several ways to diagnose kidney stones. In the event that the stone is causing pain while passing, medical attention may be needed. Imaging tests such as a CT or ultrasound may diagnose a passing stone. If the stones are still forming the kidney, there is likely no symptoms. As such, they may only be diagnosed if the patient is undergoing an X-ray or other imaging during an exam for another condition.

How are Kidney Stones Treated?

Treatment can vary greatly depending on the type of stone, how bad the pain is and the length of time you may have been experiencing symptoms. Some treatment options may include:

Passing the Stone Naturally – Most often, stones will pass on their own, as long as they are small, the pain is bearable, there are no signs of infection and the kidney is not completely blocked. Your doctor may recommend drinking extra water and pain medication.

Medication – In addition to pain management, your doctor may also prescribe a medication that helps to relax the ureter, allowing the stone to pass more freely. Your doctor may also recommend anti-nausea medications.

Surgery or Procedures – Typically, surgery for kidney stones involves a very small or no incision at all. It results in minor pain and very minimal recovery time. Surgery may be recommended if:

  • The stone fails to pass on its own
  • The pain is too severe
  • If the stone is causing infections
  • Kidney function is being affected

Types of procedures may include the following:

Shock Wave Lithotripsy (SWL) – This procure is typically used to treat stones in the kidney and ureter. The patient will be given some form of anesthesia and using X-rays or ultrasound, shock waves are repeatedly fired at the stones. This causes the stone to break into small pieces, which can pass naturally over the following few weeks. This treatment is generally considered very safe, however, there may be some side effects including some blood in the urine and some pain when some stones pass.

Ureteroscopy (URS) – URS involves passing a small scope, known as a ureteroscope, into the bladder, and up the ureter into the kidney, while a patient is anesthetized. The urologist will be able to see the stones without the need for incisions. They will then remove smaller stones using a small basket-shaped tool. If a stone is too large, they will use tools to break up the stone in order to remove it. Your doctor may also place a temporary stent, which helps to hold open the ureter to pass urine more freely. This is temporary and it will be removed in 4-10 days, on average.

Percutaneous Nephrolithotomy (PCNL) - This treatment is used when there are large stones in the kidney and is administered under general anesthesia. Your doctor will make a small incision on your back or side and insert a scope. They will then use tools to break up the large stone and use suction to remove the smaller pieces. Most often, they will place a tube that allows the kidneys to drain into a bag located outside the body. Generally, this is left for 1-4 days. Your urologist may also request X-rays to ensure there are no stones left.

Whichever method is chosen for your specific case; your doctor will want to test the stone to determine what type of stone it is. This will help to develop a treatment plan to help prevent stones in the future.

How to Prevent Stones

Generally, there is no one way to prevent kidney stones from forming again. However, there are several steps your doctor may recommend for your treatment plan, which may include any of the following:

Drink enough fluids – as mentioned previously, dehydration is a common cause of stone development. Aim for about ten 10oz glasses of water each day.

Reduce salt intake – For those with high urine calcium or Cystine, reducing sodium levels can help. The Centers for Disease Control and Prevention (CDC,) advises no more than 2,300 mg of salt per day, however, your doctor may have a more specific recommendation.

Other diet recommendations – in addition to reducing sodium intake, be sure to eat plenty of fruits and vegetables to help get the fiber, potassium, magnesium and more that all help prevent the development of kidney stones. You should also enjoy calcium-rich foods including low-fat milk, kefir, yogurt and more. Ask your doctor if a calcium supplement is right for you. You should also enjoy a diet containing less animal protein. Instead of eating these foods once or twice a day, aim for a few times each week. Your doctor will have more specific recommendations for you based on your medical history.

Medications – Depending on your specific circumstances, increasing fluids and making dietary changes may not be quite enough. In this case, your doctor may prescribe medications to help. There are many types of medications that are specifically suited based on the type of stones formed.        


While kidney stones can be very painful, the majority will pass on their own with little or no medical intervention. Be sure to drink plenty of water and enjoy a healthy diet to help the prevention of stones. Be sure to talk to your doctor if you have concerns about kidney stones or kidney health.

Access is proud to have three urologists on our team, click on each name to learn more: Nabeel Hamoui, MD, Mohammed Nazir Hamoui, MD and Omar Hamoui, MD.

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Written by S. Campbell for Access Health Care Physicians, LLC