Diet and Nutrition

Kidney Stones: The Top 10 Questions

  • The size of a kidney stone may vary--kidney stones can be tiny enough to exit the body with urine flow or large enough that they inhibit normal urine flow from the kidneys, causing serious complications and leading to severe pain and discomfort.
  • Kidney stones can lead to death in cases where they inhibit the normal urine flow from the kidneys and through the urinary tract or when an infection develops. 
  • Kidney stone treatment depends on the stone's size, location, nature, and cause.

How Big Is a Kidney Stone?

A kidney stone, also known as a renal calculus (pl. renal calculi), is a solid mass that has formed in the kidneys due to an accumulation of minerals and acid salts due to various contributing factors. The size of a kidney stone may vary--kidney stones can be tiny enough to exit the body with urine flow or large enough that they inhibit normal urine flow from the kidneys and through the urinary tract, causing serious complications and leading to severe pain and discomfort.

Kidney stones of a size smaller than 2 mm are considered tiny stones and are easily flushed out. Kidney stones 2 mm to 4 mm are considered medium-sized, while those larger than 6 mm are considered large kidney stones. Sometimes, kidney stones can be even bigger than 9 mm or 10 mm.

The size of a kidney stone is important in relation to their susceptibility to getting flushed out from the urinary tract. Smaller stones are easily flushed out, while bigger kidney stones, especially those bigger than 6 mm, are not eliminated from the urinary tract without medical intervention.

Can Kidney Stones Lead to Death?

In general, kidney stones are not a serious condition and if small, they can be flushed out of the body without any problem. However, with bigger stones, stones accompanied by signs and symptoms, and recurrent kidney stones, the situation can get a bit tricky.

Kidney stones can lead to death in cases where they inhibit the normal urine flow from the kidneys or when an infection develops. When the bacteria that caused the kidney infection enter the bloodstream, septicemia occurs, leading to death within a short period of time. Also, any permanent damage to the kidney due to urine flow obstruction can lead to kidney failure, a serious medical condition that can also lead to death if left untreated.

How Does a Doctor Check for Kidney Stones?

If a kidney stone is suspected based on your medical history and physical examination, your doctor will order various examinations and imaging tests, typically any of the following:

Blood tests reveal whether there are increased levels of uric acid, calcium, phosphorus, and electrolytes in the blood.

Urinalysis reveals information about urine excretion from the kidneys. For a better diagnosis, a 24-hour urine collection test is necessary.

An abdominal ultrasound is used to determine the sizes, locations, and shapes of the kidneys. It also helps identify the presence of kidney stones inside the urinary system as well as their locations and sizes.

The intravenous pyelogram is an imaging test that consists in injecting contrast dye into the veins in order to evaluate the function of the kidneys, ureters, and bladder.  

The retrograde pyelogram is an imaging test that uses x-ray imaging to check the kidneys, ureters, and bladder. The procedure consists in injecting contrast dye through cystoscopy directly into the ureters.

The CT scan and MRI test are both used to detect kidney stones, identify their locations in the urinary system, and determine their sizes.

Analyzing passed stones is also helpful. By determining the nature of the stones created in the kidneys, your doctor can formulate a plan in order to prevent them from reoccurring in the future.

How Are Kidney Stones Treated?

Kidney stone treatment depends on the stone's size, location, nature, and cause. Small stones presenting no or minimal symptoms require only supportive treatment. This means drinking plenty of water every day, at least 2 liters a day in order to help flush out the stones from the kidneys as soon as possible. Over-the-counter painkillers are also helpful for mild kidney stone pain.

For larger kidney stones causing various signs and symptoms for which conservative measures provide no relief, extensive treatment such as one of the following is required:

  • Shockwave lithotripsy – a minimally invasive procedure that consists in using strong ultrasound waves to break up the stones into tiny pieces. Later, these pieces are flushed out through normal urine flow.
  • Ureteroscopy – a procedure that consists in removing the kidney stones from the urinary system with the help of a ureteroscope.
  • Percutaneous nephrolithotomy – an invasive surgical procedure that removes the large and complex kidney stones through a small incision in the back.

The most important thing when it comes to kidney stones is to prevent them from occurring in the first place. Also, kidney stones tend to reoccur, so knowing their nature will tell you what you can do to prevent them from reoccurring. Preventing kidney stones requires lifestyle changes, and preventing recurrence requires the same, combined with the use of medications.

Do You Need Surgery to Remove Kidney Stones?

Bigger stones or those that involve complications require surgical treatment. There are three main surgical techniques used for kidney stones:

  • Shockwave lithotripsy
  • Ureteroscopy and laser lithotripsy
  • Percutaneous nephrolithotomy

Shockwave lithotripsy is commonly used for the treatment of small to medium-sized kidney stones. This surgical procedure consists in using focused, intense sound waves to shatter the stones into tiny pieces in order for them to get eliminated naturally later with the help of urine flow. Shockwave lithotripsy is usually performed as an outpatient procedure under general anesthesia. The procedure is minimally invasive and involves minimal postoperative discomfort.

Ureteroscopy and laser lithotripsy are the preferred surgical methods for small to medium-sized kidney stones located in any part of the urinary tract. The procedure consists in using a small scope, which is inserted through the urinary opening into the urethra, the urinary bladder, and ureters, and up into the kidneys until the kidney stones are visible. Once the stones have been located in the urinary system, they are targeted and broken up with a laser into tiny pieces. These tiny pieces are then eliminated from the urinary system through normal urine flow. Ureteroscopy and laser lithotripsy are performed under general anesthesia as well.

Percutaneous nephrolithotripsy is a surgical procedure used for the removal of large or complex kidney stones. This procedure is also used when there are a large number of kidney stones in a single kidney. A channel is created from the drainage system of the kidney through a small incision in the back. Once the kidney stones are seen, they are removed from the kidney using vacuum suction. Usually, a drainage tube is left in place for a couple of days in order to help the kidney drain. Rarely, a second percutaneous nephrolithotripsy is required, usually for complicated stones or for those extremely large in size. Despite being an invasive surgical procedure, percutaneous nephrolithotripsy is safe and very effective.

How Long Does It Take to Recover From Kidney Stone Surgery?

Surgical treatment is usually required for kidney stones bigger than 6 mm and for complex kidney stones. Smaller kidney stones, especially those smaller than 2 mm, can be flushed out from the urinary system with normal urine flow.

Surgery is needed if a kidney stone does not pass with urine within a certain period of time, if it causes severe pain and discomfort, if it causes constant bleeding or damages the kidney tissue, if it has grown larger, or if it blocks normal urine flow. Kidney stones treatment has greatly improved and in most cases, they can be removed using minimally-invasive surgical techniques like shockwave lithotripsy or ureteroscopy and laser lithotripsy. These procedures are usually performed in an outpatient setting under general anesthesia. The recovery time is relatively short. Patients can return to their normal daily activities within a few days.

Another surgical treatment available for big and complex kidney stones is percutaneous nephrolithotomy. This is a more invasive surgical procedure that consists in removing the kidney stones through a small incision in the patient's back. After all of the kidney stones have been successfully removed, a drainage tube is left in place for a couple of days in order to help drain the kidney. Rarely, a revision or second surgery is necessary. All this means that the recovery period after percutaneous nephrolithotomy is longer, usually more than 2 weeks.

How Long Does It Take to Pass a Kidney Stone?

Kidney stones are solid masses created inside the kidneys due to various causes. Small kidney stones, usually those smaller than 2 mm, can be flushed out of the urinary system without causing any problem. However, bigger kidney stones are very painful and often require surgical treatment to be removed. 

Passing a kidney stone can be quite painful. They cause muscle spasms and pain in the lower back, lower abdomen, and groin area, along with many other signs and symptoms. How long it takes for a kidney stone to exit depends on its size and location. 

Smaller stones and those located close to the bladder are more likely to pass on their own and quickly. If the stone is located in the ureters and has a size smaller than 2 mm, it will usually be eliminated within 8 days. For kidney stones between 2 mm and 4 mm located in the ureters, the time needed to pass them is about 12 days, while for kidney stones between 4 and 6 mm, it is about 22 days. In general, most kidney stones are eliminated within 40 days.

Certain types of medications such as antispasmodics can help pass stones more quickly. These medications speed up the flushing process, and the kidney stones can be eliminated from the urinary system in about 5 to 7 days.

The American Urological Association suggests a waiting period of about 2 months. If the stones are not eliminated within the period, proper treatment is required. This is especially true in cases where certain complications arise while waiting for a stone to get flushed out on its own from the urinary system. Common kidney stone complications include nausea, vomiting, fever, chills, ureter blockage, and decreased kidney function.

What Are the Symptoms of a Kidney Infection?

Kidney stones can cause a kidney infection. A kidney infection, commonly known as pyelonephritis, is an infection that spreads to the kidneys from the lower parts of the urinary tract like the bladder and ureters. In general, a kidney infection occurs as a complication of a bladder infection and is a potentially serious medical condition. A kidney infection can lead to permanent kidney damage, kidney failure, sepsis, and even death.

Among the common signs and symptoms of a kidney infection are the following:

  • Painful urination
  • Frequent urination
  • An urge to urinate
  • Back pain on one side
  • Nausea and vomiting
  • High fever and chills
  • Confusion
  • Cloudy or smelly urine
  • Blood or pus in the urine

At the start, the signs and symptoms are mild to moderate, similar to those of a bladder infection. However, once the infection has spread to the kidneys, the signs and symptoms tend to get worse over a very short period of time.

Do Kidney Stones Cause Nausea?

Yes, kidney stones can cause nausea. Nausea and vomiting are common signs of kidney stones, especially in cases where a kidney stone is complicated with a kidney infection.

Nausea is a sensation of discomfort and uneasiness in the upper part of the abdomen accompanied with an involuntary urge to vomit. Vomiting, commonly known as emesis, is the involuntary expulsion of the stomach's contents through the mouth. The nausea caused by kidney stones may or may not be followed by vomiting. When they occur over a long period of time, nausea and vomiting can be debilitating.

How Do You Know If You Have Kidney Stones?

Kidney stones can be a real nightmare, and the pain they cause is often described as the worst pain possible. However, there are certain signs that signify a possible kidney stone. The sooner you know about any kidney stones you may have, the more time to you have to deal with it before any real pain starts.

Warning signs of kidney stones include frequent urination, the presence of blood in the urine, and repeated urinary tract infections.