If you have sudden, sharp pain in your side or back just below your ribs, you may have kidney stones. Kidney stones are hard clusters of minerals and salts that form in your kidneys and can move through your urinary tract, and they often come with pain that arrives in waves, along with changes in your urine or an upset stomach.
Those symptoms can help your doctor suspect a kidney stone, but a CT scan can confirm whether a stone is present and show its size and exact location.
In this guide, you’ll learn the most common signs of kidney stones, what the pain usually feels like, how long symptoms tend to last and how a CT scan gives you and your doctor the answers you need.
How Do You Know If You Have Kidney Stones?
You may suspect a kidney stone when pain in your side or lower back appears suddenly and returns in waves. Pink or cloudy urine, a burning feeling when you urinate or nausea that shows up alongside the pain are other common symptoms.
If your doctor suspects a kidney stone, they may use a urine test, blood work and imaging to find out what is causing your symptoms. A CT is the most accurate scan for kidney stones because it can show how many stones you have, how large they are and where they are located. That information helps confirm the diagnosis and guide your treatment.
What Are Signs of Kidney Stones?
Kidney stones can form when your urine contains high levels of minerals and other substances, such as calcium, oxalate and uric acid. If there isn’t enough fluid to dilute them, these substances can stick together and form crystals. Over time, the crystals can grow into a kidney stone.
Some stones stay as small as a grain of sand, while others grow large enough to get stuck as they move through the urinary tract.
The most common signs of kidney stones include:
- Pain in the lower back, side or belly that comes and goes
- Pain that spreads toward the lower stomach and groin
- Urine that looks pink, red or brown
- Urine that appears cloudy or smells unusual
- A burning feeling while you urinate
- A frequent urge to go, or passing only small amounts
- Nausea and vomiting
- Fever or chills, which can point to an infection
About 1 in 10 people develop a kidney stone at some point, and they’re most common in men in their 30s and 40s. Your risk increases if you don’t drink enough fluids, eat a diet high in sodium or animal protein, carry extra weight or have a family history of stones.
What Do Kidney Stones Feel Like?
Not every kidney stone is painful. The pain usually starts once the stone moves into the ureter, which is the narrow tube that carries urine from your kidney to your bladder. When a stone blocks that path, urine backs up, the kidney swells and the ureter spasms.
Kidney stone pain tends to be sharp and intense, often starting in the side or back just below the ribs. It may build and ease in waves rather than staying steady, which doctors sometimes call “colicky pain.” Many people also feel the pain spread toward the groin as the stone moves.
You may notice that kidney stone pain usually doesn’t improve when you shift positions the way a pulled muscle does. Lying down, stretching or standing up rarely brings relief. The location can also change over the course of a day or two as the stone moves farther along your urinary tract.
How Long Do Kidney Stone Symptoms Last?
Symptoms of kidney stones usually last as long as the stone is moving through your urinary tract. Around 80% of kidney stones pass on their own, and size is the biggest factor in how long that takes.
A stone under 4 millimeters often clears in a week or two. Bigger stones can take closer to three weeks. Once the kidney stone reaches your bladder, it typically leaves the body within a few days, and the pain often eases at that point.
You may not need a procedure to remove a kidney stone. Most stones smaller than 5 millimeters pass on their own, and stones between 5 and 10 millimeters pass about half the time. Larger stones often need treatment. If four to six weeks go by and you still haven’t passed a stone, follow up with your doctor. They may recommend imaging to check the stone’s size and location and see if it’s blocking the flow of urine.
Can You Have Kidney Stones Without Symptoms?
Smaller stones can stay in the kidney for a long time without causing pain or noticeable changes in your urine. Doctors often find smaller kidney stones by chance when you have imaging for another reason, such as abdominal pain or a routine follow-up scan.
Finding a kidney stone before it causes symptoms gives you and your doctor a chance to monitor it and take steps that may keep it from growing. That may include drinking more water or making changes to your diet. Because having one kidney stone increases your chances of developing another, your doctor can also watch for new stones over time.
When Should You See a Doctor for Kidney Stone Symptoms?
Talk to your doctor if you have pain in your side or back between your ribs and hip, or if you notice changes in your urine. The following symptoms need prompt medical attention:
- Pain intense enough that you can’t sit still or get comfortable
- Pain paired with nausea and vomiting
- Fever or chills
- Visible blood when you urinate
- Difficulty urinating or an inability to go at all
These can signal a blockage or an infection that needs care right away. A stone that stops the flow of urine can cause the kidney to swell, and untreated blockages raise the risk of kidney infection or reduced kidney function. If you have fever or chills along with kidney stone pain, or severe pain you can’t control, you may need to contact your doctor right away or go to the emergency room.
Getting evaluated early removes the guesswork and lets your doctor decide whether to let the stone pass on its own or step in with treatment.
What Is Commonly Misdiagnosed as Kidney Stones?
Pain in the flank or lower abdomen has plenty of possible sources, and more than a few of them mimic a stone. Conditions frequently confused with kidney stones include:
- Urinary tract infections and kidney infections
- Appendicitis
- Diverticulitis
- Gallstones
- Ovarian cysts
- Muscle strain in the lower back
- A hernia
These conditions can cause similar symptoms, so it may be hard to tell what’s wrong based on how you feel alone. Your doctor may order a CT scan of your abdomen and pelvis to look for a kidney stone and check for other possible causes of your pain.
The scan shows your organs, soft tissues, blood vessels and bones in detail, helping your doctor understand what may be causing your symptoms and choose the right next step.
How Are Kidney Stones Diagnosed?
To find out whether you have a kidney stone, your doctor may use a combination of urine tests, blood work and imaging:
- A urine test looks for blood, mineral crystals and any sign of infection.
- Blood work measures kidney function and looks for high levels of calcium, uric acid or other substances tied to stone formation.
- Imaging shows the stone itself, including how large it is and where it has traveled.
Kidney stones show up on CT scans with remarkable clarity because CT creates thin cross-sectional images of your body that can be layered into a detailed 3D view. Nearly every stone type is visible on CT, including small stones and uric acid stones that a standard X-ray can miss.
American Health Imaging uses advanced multi-slice, low-dose CT technology to produce sharp, high-quality images while limiting radiation exposure. During a CT scan for kidney stones, your imaging team may position you on your stomach rather than your back, which can help show whether a stone has reached the bladder.
What If You Have Symptoms of Kidney Stones, But CT Didn’t Show Them?
If your CT scan doesn’t show a kidney stone, the results can still help explain what may be causing your symptoms. One common explanation is that the stone has already passed, and the soreness you’re feeling is irritation left behind in the ureter. If the stone has already passed, your doctor can focus on treating any lingering irritation or symptoms.
The other possibility is that something else is behind your symptoms, and a CT of the abdomen and pelvis is built to catch it. The same images that rule out a stone can reveal inflammation, an infection or another finding worth following up on.
If the scan points to another cause, you and your doctor will have clearer information about what may be causing your symptoms and what to do next.
Schedule a CT Scan To See If You Have Kidney Stones
American Health Imaging uses advanced multi-slice, low-dose CT technology to help find kidney stones clearly and accurately. A board-certified, subspecialized radiologist reads your exam, and you’ll receive a Scanslated® report by text within 48 hours after your report is finalized. Your Scanslated® report uses plain language and diagrams to help you understand where a stone is, how large it is and what else your scan found.
Our imaging centers are in-network with 99% of major insurance plans, offer same-day appointments and provide CT imaging at up to 60% less than hospital imaging. With a 97% patient satisfaction rating, your imaging team supports you from check-in to results. You can also call your nearest center for a cost estimate before your appointment.
Talk to your doctor about imaging and schedule your CT scan with American Health Imaging today.