Kidney Stones: What You Need to Know

What Are Kidney Stones?

What are kidney stones?

Kidney stones are solid masses or crystals that form from substances (like minerals, acids and salts) in your kidneys. They can be as small as a grain of sand or — rarely — larger than a golf ball. Kidney stones are also called renal calculi or nephrolithiasis

Depending on the size of your kidney stone (or stones), you may not even realize that you have one. Smaller stones can pass through your urinary tract in your pee with no symptoms. Large kidney stones can get trapped in your ureter (the tube that drains urine from your kidney down to your bladder). This can cause pee to back up and limit your kidney’s ability to filter waste from your body. It can also cause bleeding.

It can take as long as three weeks for kidney stones to pass on their own. Even some small stones can cause extreme pain as they go through your urinary tract and out of your body. You may need a provider to break up and remove a stone that can’t pass on its own.

How common are kidney stones?

About 1 in 10 people will get a kidney stone during their lifetime. They’re most common in men in their 30s and 40s. They’re also more common among non-Hispanic white people.

Symptoms and Causes:

What are the symptoms of kidney stones?

The most common symptom of kidney stones is pain in your lower back, belly or side (flank pain). It might feel like it extends from your groin to your side. It can be a dull pain or sharp and severe. It’s sometimes called colicky pain because it can get worse in waves.

Other kidney stone symptoms include:

1. Nausea and vomiting.
2. Bloody pee.
3. Pain when you pee.
4. Inability to pee.
5. Feeling the urge to pee a lot.
6. Fever or chills.
7. Cloudy or foul-smelling pee.

What causes kidney stones?

Your pee contains minerals, acids and other substances, like calcium, sodium, oxalate and uric acid. When you have too many particles of these substances in your pee and too little liquid, they can start to stick together, forming crystals or stones. Kidney stones can form over months or years.

Types of kidney stones

Stones are named for the type of crystals they’re made up of:

Calcium-oxalate and calcium phosphate stones.

Calcium-based stones can form when you eat high-oxalate or low-calcium foods and aren’t drinking enough fluids. Calcium-oxalate stones are the most common type of kidney stones.

Uric acid stones.

Eating animal proteins (beef, poultry, pork, eggs and fish) can cause uric acid stones to form.

Struvite stones.

Bacterial infections can cause struvite stones. Repeated infections can lead to a staghorn calculus, a very large kidney stone that usually needs to be surgically removed.

Cystine stones.

An inherited condition called cystinuria causes cystine stones. Cystine is a substance made of two cysteine amino acids bound together.

How Do They Affect the Body?

Small stones may pass without symptoms.

Larger stones can block the urinary tract, causing pain, infection, or kidney damage.

Passing a stone can take up to three weeks and may be very painful.

Medications:

If you have a kidney stone that can pass on its own and isn’t causing infection, a provider may prescribe or recommend medications to:

Relax your ureter to help stones pass.

Commonly prescribed medicines include tamsulosin and nifedipine.

Manage nausea and vomiting.

Manage pain. Even small stones that can pass on their own can be very painful. Your healthcare provider may prescribe medications or make recommendations for over-the-counter (OTC) medications to manage the pain. Ask your provider before taking ibuprofen. It can increase the risk of kidney failure if you take it during an acute attack of kidney stones — especially if you have underlying health conditions.

How to Prevent Kidney Stones

1. Drink Plenty of Water

Aim for at least 2.5–3 liters (10–12 cups) of water a day.

Staying well-hydrated keeps your urine dilute and prevents crystals from forming.

A good rule: Your pee should be light yellow or clear.

2. Limit Sodium Intake

High sodium (salt) levels increase calcium in your urine.

Avoid salty snacks, canned soups, processed foods, and restaurant meals.

Keep sodium under 2,300 mg/day (about 1 teaspoon of salt).

3. Eat Calcium-Rich Foods (but not too much)

Don’t avoid calcium—just get it from food, not supplements.

Dairy products like milk, yogurt, and cheese are good sources.

Pair calcium-rich foods with oxalate-rich ones to help bind them in the gut, preventing stone formation.

4. Reduce Oxalate-Rich Foods

Oxalates can bind with calcium to form stones.

Limit:

Spinach

Beets

Rhubarb

Nuts and nut butters

Chocolate

Sweet potatoes

Especially important if you've had calcium-oxalate stones before.

5. Limit Animal Protein

Eating too much red meat, poultry, eggs, and seafood can raise uric acid levels.

Try to have more plant-based meals and moderate meat intake.

6. Avoid Excessive Sugar and Soda

Sugary drinks and sodas (especially cola) can raise stone risk.

Limit or avoid drinks with high fructose corn syrup and phosphoric acid.

7. Maintain a Healthy Weight

Obesity and metabolic issues can increase stone risk.

Exercise regularly and eat a balanced diet to keep your weight in check.

Who’s at Risk?

Certain medical conditions increase the risk of developing kidney stones, including:

1. Diabetes
2. Gout
3. Cystic fibrosis
4. High blood pressure
5. Obesity
6. Osteoporosis
7. Parathyroid disorders
8. Inflammatory Bowel Disease (IBD)
9. Kidney cysts
10. Genetic disorders like cystinuria or primary hyperoxaluria
11. Paralysis (hemiplegia or paraplegia)

How Are Kidney Stones Treated?

For Small Stones:

Drink plenty of fluids to help flush the stone out.

Your doctor may prescribe medications to:

Relax your ureter (e.g., tamsulosin, nifedipine)

Control nausea, vomiting, and pain

Note: Always talk to your provider before using over-the-counter pain relievers like ibuprofen—it can be harmful during a kidney stone episode, especially for people with pre-existing kidney issues.

For Larger Stones:

If a stone is too large to pass, causes infection, or blocks urine flow, your doctor may recommend procedures like:

Shock wave therapy (ESWL) to break up the stone

Ureteroscopy to remove or break the stone

Surgical removal (for very large or complicated stones)

Takeaway

Kidney stones are painful but treatable. Staying hydrated, watching your diet, and managing underlying health issues can go a long way in preventing them. If you’re experiencing symptoms, don’t wait—early treatment can save you from serious complications.