Kidney stones, also called nephrolith or renal calculi, are the most common health condition associated with the urinary system. Every year, there are about 600,000 kidney stone cases in the United States.

The stones are hard mineral fragments that can form in your kidneys. Often, they’re small enough to exit your body through your urine. But if they’re too large, you may need medical assistance to have them broken up or removed.

If you think you might have a kidney stone, seek medical attention right away. In particular, a fever with a kidney stone or a urinary tract infection (UTI) with a kidney stone are surgical emergencies.

Serious complications from kidney stones are rare when addressed early but can be severe if left untreated.

Read on to learn more about the symptoms of kidney stones.

Kidney stones are hard collections of salt and minerals often made up of calcium or uric acid. They form inside the kidney and can travel to other parts of the urinary tract.

Stones vary in size. Some are as small as the period at the end of this sentence — a fraction of an inch. Others can grow to be a few inches across. Some kidney stones can become so large they take up the entire kidney.

A kidney stone forms when too much of certain minerals in your body accumulate in your urine. When you aren’t well-hydrated, your urine becomes more concentrated with higher levels of certain minerals. When mineral levels are higher, it’s more likely that a kidney stone will form.

Stones are more common in men. In the United States, around 11 percent of men and 6 percent of women will develop kidney stones at least once during their lifetime.

Kidney stones are also more common in people who have diabetes or obesity. Kidney stones can also be caused by a genetic condition called cystinuria.

Smaller kidney stones that remain in the kidney often don’t cause any symptoms. You might not notice anything is amiss until the stone moves into your ureter — the tube that urine travels through to get from your kidney to your bladder.

If the stone is small enough, it’ll continue from your bladder to your urethra and exit your body through your urine. The smaller the stone, the more likely it’s to pass on its own, and the more quickly the process will happen.

Most stones that pass naturally will take 31 to 45 days. If a stone hasn’t passed within this timeframe, it’s important to get medical attention, as the stone could increase the risk of kidney damage and other complications.

A doctor may advise you to drink a lot of water to help with this process. They may also have you strain your urine in order to catch the stone. Analyzing the stone can help determine the underlying cause.

Kidney stones are typically very painful. Most stones will pass on their own without treatment. But you may need a procedure to break up or remove stones that don’t pass.

If you have a very small kidney stone, you may not have any symptoms as the stone passes through your urinary tract. But if your kidney stone is larger, you’ll likely have some symptoms.

Outlined below are 8 signs and symptoms of kidney stones.

1. Pain in the back, belly, or side

Kidney stone pain — also known as renal colic — is one of the most severe types of pain imaginable. Some people who’ve experienced kidney stones compare the pain to childbirth or getting stabbed with a knife.

The pain is intense enough to account for more than half a million visits to emergency rooms each year.

Usually, the pain starts when a stone moves into the narrow ureter. This causes a blockage, which causes pressure to build up in the kidney. The pressure activates nerve fibers that transmit pain signals to the brain.

Kidney stone pain often starts suddenly. As the stone moves, the pain changes location and intensity.

Pain often comes and goes in waves, which is made worse by the ureter contracting as it tries to push the stone out. Each wave may last for a few minutes, disappear, and then come back again.

You’ll typically feel the pain along your side and back, below your ribs. It may radiate to your belly and groin area as the stone moves down through your urinary tract.

Large stones can be more painful than small ones, but the severity of the pain doesn’t necessarily relate to the size of the stone. Even a little stone can be painful as it moves or causes a blockage.

2. Pain or burning during urination

Once the stone reaches the junction between your ureter and bladder, you’ll start to feel pain when you urinate. Your doctor might call this dysuria.

The pain can feel sharp or burning. If you don’t know you have a kidney stone, you might mistake it for a UTI. Sometimes you can have an infection along with the stone.

3. Urgent need to go

Needing to go to the bathroom more urgently or frequently than usual is another sign that the stone has moved into the lower part of your urinary tract.

You may find yourself running to the bathroom or needing to go constantly throughout the day and night.

Urinary urgency can also mimic a UTI symptom.

4. Blood in the urine

Blood in the urine is a common symptom in people with kidney stones. This symptom is also called hematuria.

The blood can be red, pink, or brown. Sometimes the blood cells are too small to see without a microscope (called microscopic hematuria), but your doctor can test your urine to see if it contains blood.

5. Cloudy or smelly urine

Healthy urine is clear and doesn’t have a strong odor. Cloudy or foul-smelling urine could be a sign of an infection in your kidneys or another part of your urinary tract.

One 2021 study found that about 16 percent of people with acute kidney stones had a UTI.

Cloudiness is a sign of pus in the urine, or pyuria. The smell can come from the bacteria that cause UTIs. An odor may also come from urine that’s more concentrated than usual.

A UTI with a kidney stone is considered a surgical emergency — with or without a fever.

6. Going a small amount at a time

Large kidney stones sometimes get stuck in a ureter. This blockage can slow or stop the flow of urine.

If you have a blockage, you may only urinate a little bit each time you go. Urine flow that stops entirely is a medical emergency.

7. Nausea and vomiting

It’s common for people with kidney stones to have nausea and vomiting.

These symptoms happen because of shared nerve connections between the kidneys and the GI tract. Stones in the kidneys can trigger nerves in the GI tract, setting off an upset stomach.

Nausea and vomiting can also be your body’s way of responding to intense pain.

8. Fever and chills

Fever and chills are signs of an infection in your kidney or another part of your urinary tract. This can be a serious complication of a kidney stone. It can also be a sign of other serious problems besides kidney stones. Any fever with pain requires urgent medical attention.

Fevers that occur with an infection are usually high — 100.4˚F (38˚C) or more. Chills or shivering often occur along with the fever.

Although anyone can develop a kidney stone, there are some factors that can increase your risk. Some risk factors can’t be changed, while others can be controlled or modified.

You may be at a higher risk of developing kidney stones if:

  • you’re male
  • you’re non-Hispanic white
  • you’ve had kidney stones before
  • somebody in your family has had kidney stones
  • you don’t drink enough fluids
  • your diet is high in protein, salt (sodium), and/or sugar
  • you have overweight or obesity
  • you have diabetes
  • you have gout
  • you have polycystic kidney disease
  • you take calcium-based antacids or diuretics (water pills)
  • you’ve had gastric bypass surgery or other gastrointestinal surgery
  • you’re of reproductive age and have had one or more pregnancies
  • you eat a diet that’s high in red meat or high in oxalates
  • you have a condition that causes high levels of cystine, uric acid, calcium, or oxalate in your urine

Call your doctor if you have any symptoms of kidney stones. Get medical help right away if you have the following symptoms, which could indicate that you have an infection or other serious complication:

  • pain so severe that you can’t get comfortable
  • nausea, vomiting, fever, or chills with the pain
  • blood in your urine
  • trouble urinating

Kidney stones are hard collections of salt and minerals that form in your kidneys and can travel to other parts of your urinary system.

Stones cause symptoms like pain, trouble urinating, cloudy or smelly urine, nausea, and vomiting.

Some stones will pass on their own. Others need treatment with sound waves or surgery to break them up or remove them.

Call your doctor if you have any symptoms of kidney stones. The earlier you get treatment, the less likely you’ll have complications from kidney stones.

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