What Are Kidney Stones?

Kidney stones—also known as renal calculi—are hard deposits made of minerals that build up in your urinary tract and form in your kidneys. Sometimes kidney stones can stay small in size and not produce any symptoms, while other stones can grow and cause pain, nausea, and blood in your urine.

Treatments for kidney stones usually depend upon their size and your symptoms. You may take over-the-counter pain relievers and wait for the stone to pass or a healthcare provider may perform medical procedures to remove or break up the stone. Your provider may also recommend steps to prevent future kidney stones from developing.

An estimated 10.1% of the United States population develop kidney stones once in their lifetimes. That said, knowing the symptoms, learning when to seek care, and understanding your treatment options is important.

Types of Kidney Stones

Healthcare providers classify kidney stones by what minerals and compounds they are made of. Your kidney stones can be made of any of the following materials:

• Oxalate: Calcium oxalate stones are the most common kidney stone type, accounting for 67% of all cases. Excess calcium levels in the body and lower urinary pH levels can lead to calcium oxalate stones developing. Unfortunately, both calcium oxalate and calcium oxalate stones have a high rate of happening again.
• Calcium phosphate: Those who eat foods high in protein (more than 1 milligram per kilogram of their body weight) tend to have calcium-containing stones because excess protein can release calcium into your urine.
• Uric acid: Uric acid stones are the third-most-common kidney stone type, occurring in 8% of people with stones. If you eat a diet high in purine-containing foods (such as meats and fish), you may be at greater risk for uric acid stones.
  
• Struvite: Struvite stones are very rare and occur in about 3% of people with kidney stones. People who experience chronic urinary tract infections may be more vulnerable to developing struvite stones.
• Cystine: Cystine stones are the least common kidney stone type. In fact, less than 1% of people with stones develop this type. Cystine stones may be caused by a genetic disorder that affects your kidney's ability to absorb cystine, a compound found in the body. As a result, too much cystine builds up in your urine, leading to the formation of kidney stones.
  

Symptoms

Pain is the most common kidney stone symptom. Generally, the larger your kidney stones are, the more discomfort you'll experience. These painful episodes typically last between 20 minutes and one hour in duration. It's also very common for the pain to come and go. You're likely to experience the most pain in your back, stomach, sides, and pelvic area. The good news: once the stones pass, the pain will usually go away.

Other kidney stone symptoms include:

• Blood in the urine
• Smelly urine
• Frequent urination
• Nausea
• Vomiting
• Cramping
• Stomach aches
• Sweating
• Restlessness
• Chills
• Fever
• Fatigue
  

Causes

Kidney stones can develop due to a number of factors. These include:

• Dehydration: If you don't drink enough fluids, the compounds in your urine have more time to form stones. Signs of dehydration include dark-colored urine and thirst.
• Dietary intake: Eating foods high in certain compounds, such as protein, oxalates, carbohydrates, or sodium can promote kidney stone formation.
• Family history: Research suggests that you are more likely to develop kidney stones if you have a parent or sibling who also has or had kidney stones.

Diagnosis

If you have symptoms of a kidney stone, it's best to see your healthcare provider as soon as possible to reduce pain and prevent the risk of complications. Your provider will first perform a physical exam and learn about your medical history to assess your symptoms. They will likely also order additional diagnostic testing, which may include:

• Bloodwork: Blood tests can assess how well your kidneys are working or if you could have an infection present.
• Urine testing: A provider can look for the presence of blood, white blood cells, or other compounds in your urine.
  
• Imaging studies: Medical imaging, such as an X-ray, computed tomography (CT) scan, or ultrasound may help your healthcare provider identify if a stone is present and if the stone is keeping urine from leaving your kidney.

Sometimes, a healthcare provider may be able to tell what the stone is made of by looking at it from a CT scan and stone analysis. For example, calcium stones may appear denser than stones made from cystine or magnesium ammonium phosphate.

Treatment

Healthcare providers can recommend medical interventions and supportive care to help you reduce symptoms and get rid of your kidney stones.

Medical Interventions

A urologist (or, a doctor who specializes in the urinary tract) will likely work with your primary care provider to remove your kidney stones. They may use any of the following procedures including:

• Shock wave lithotripsy: Uses shock waves to help break kidney stones into smaller parts, making the stones easier to pass. Although the procedure is not invasive (meaning, a surgeon will not cut you open), you will typically receive anesthesia to make the process more tolerable.
• Cystoscopy or ureteroscopy: Inserts a small, thin instrument with a camera on it to identify the stone and either removes the stone or uses a laser to break up the stone into very small pieces.
• Percutaneous nephrolithotomy: Involves cutting into your back to access your kidney. This procedure is usually for larger stones or ones that may be severely obstructing your ability to pass urine.
  

Supportive Care

Supportive care for kidney stones will focus on the following:

• Taking non-steroidal anti-inflammatory drugs (NSAIDs): These medications include Advil (ibuprofen) and Naprosyn (naproxen sodium). You may take them to manage mild to moderate kidney stone pain. Your healthcare provider may also prescribe Toradol (ketorolac) if over-the-counter medication isn't reducing pain.
  
• Using opioid pain relievers: Healthcare providers may prescribe opioid pain relievers such as morphine or hydrocodone to relieve severe pain related to kidney stones.
• Increasing hydration: Drinking more fluids or receiving fluids via an intravenous (IV) line can help your kidney stones move faster through your urinary tract.

How to Prevent Kidney Stones

If you have a family history of kidney stones, preventive measures can be important to avoid future stones from developing. Common ways to prevent kidney stones include:

• Staying hydrated with water or fluids with citrate (e.g., lemonade or orange juice)
• Reducing your salt intake
• Avoiding soda and other fizzy drinks
• Keeping calcium-rich foods in your diet

If you've had a kidney stone in the past, your healthcare provider may also prescribe certain medications or supplements to help reduce your risk of developing stones again. Make sure to take these medications as instructed to lower your chances of having another kidney stone.

Complications

Although severe complications are rare, kidney stones can lead to kidney obstruction. This means the stone is so large that urine cannot leave the kidneys. Your urine may become infected and you might develop sepsis or a severe urinary tract infection that can be life-threatening. Additionally, research suggests that 2% to 3% of people with kidney stones may also experience end-stage kidney failure. In order to lower your risk of these complications, seek care immediately.

Living With Kidney Stones

Kidney stones cause more than half a million visits to the emergency room in the United States each year. Because kidney stones can have a high rate of coming back, it's important to see a healthcare provider to test your stones if possible so you can make the necessary dietary and lifestyle changes that can reduce your risk for more stones. By making healthy efforts to stay hydrated and following your provider's treatment plan, you can pass kidney stones quickly and lower your chances of developing them again.