Many kidney stones cause no symptoms at all until the moment they start to move. Then the signs of kidney stones can hit fast and hard, often with sudden flank pain, nausea, and blood in the urine. This guide breaks down the early warning signs, the symptoms of kidney stones that show up as a stone travels, and the red flags that mean you need care right away.
Can You Have a Kidney Stone Without Symptoms?
Yes. A kidney stone can stay inside the kidney for months or years and cause nothing you would notice. Most stones stay silent because they have not moved into a spot where they block urine flow. A 2023 study of 677 patients with ureteral stones found that 6.4 percent had no symptoms at all, and these silent stones were often larger and more likely to cause swelling in the kidney than the ones that did cause pain.
Research tracking the natural course of stone disease also shows that only about 20 percent of people with a known silent stone go on to develop symptoms in a given year. This is exactly why routine imaging sometimes turns up silent kidney stones nobody knew were there.
Early Signs of Kidney Stones
The early signs of kidney stones tend to be mild and easy to shrug off. A dull ache in the back or side, a small amount of blood in the urine, or the urge to pee more than usual can all show up days before the pain becomes severe.
Flank or Back Pain That Comes in Waves
The most recognizable of all signs of kidney stones is flank pain, a deep ache below the ribs on one side of the back. Unlike a pulled muscle, this pain does not stay steady. It builds, peaks, eases off, then builds again in cycles that can last twenty minutes to an hour. Doctors call this pattern renal colic, and it happens because the ureter squeezes and spasms as it tries to push the stone along. The pain often starts in the back and shifts location as the stone moves lower into the urinary tract.
Changes in Urine Color, Smell, or Frequency
A stone scrapes against the lining of the urinary tract as it moves, which is why blood in urine kidney stone cases are so common. Urine may turn pink, red, or cola colored, or the blood may only show up on a lab test. Cloudy urine, a strong or foul smell, and needing to urinate more often but in smaller amounts are also common early clues. These urinary changes frequently show up before the pain becomes intense enough to send someone to urgent care.
Signs a Kidney Stone Is Actively Passing
Once a stone enters the ureter, the signs of kidney stones shift from a background ache to sharp, radiating pain, and nausea is the two clearest markers that a stone is on the move.
Sharp Pain Radiating to the Groin
As the stone travels down the ureter toward the bladder, pain that started in the back typically spreads to the lower abdomen and groin. This is one of the clearest kidney stone emergency signs patients describe: a stabbing pain that can radiate to the testicles in men or the labia in women. The pain often gets worse right before the stone reaches the bladder, then eases sharply once it passes through.
Nausea and Vomiting
Severe pain from a moving stone triggers the same nerve pathways that control the stomach, so nausea and vomiting are common companions to renal colic. This is not just discomfort; it is the body reacting to a real physical obstruction. Vomiting that will not stop, combined with an inability to keep fluids down, is one reason many people with kidney stone pain end up in the emergency room.
Do Kidney Stone Signs Differ Between Men and Women?
Kidney stone symptoms in men more often include pain that radiates into the testicles, since the male urethra is longer and the anatomy is closer to the path of a descending stone. Kidney stone symptoms in women are more likely to be felt as pelvic pain, cramping, or lower abdominal pressure, which gets mistaken for menstrual cramps, ovarian cysts, or a urinary tract infection.
This overlap with gynecologic symptoms can delay diagnosis in women, since the pain does not always point clearly to the kidneys. Anyone with new, unexplained pelvic or groin pain paired with urinary changes should mention kidney stones as a possibility, regardless of gender.
Red Flag Signs That Need Emergency Care
Most stones pass with fluids and pain control at home, but certain kidney stone emergency signs point to a complication that needs same-day treatment. Fever and an inability to urinate top that list.
Fever and Chills (Possible Infection)
A fever above 100.4°F combined with flank pain is never something to wait out. When a stone blocks the ureter and bacteria build up behind it, infected urine can back up into the kidney. Urology guidelines from the American Urological Association and European Association of Urology describe an infected, obstructed kidney as a true urological emergency, since bacteria can enter the bloodstream and cause sepsis within hours. This combination requires urgent imaging and, often, a procedure to drain the kidney before the stone itself is treated.
Inability to Urinate
If both kidneys are affected, or if a single functioning kidney becomes completely blocked, urine output can drop to almost nothing. This is a medical emergency, not a symptom to monitor at home. Complete inability to pass urine, paired with pain and a swollen, tender abdomen, means the kidney is under pressure it cannot relieve on its own, and permanent damage can start within days if the blockage is not cleared.
Kidney Stone Signs vs Other Conditions (UTI, Back Strain)
A kidney stone vs UTI comparison is often confusing because both can cause burning urination and the urge to go frequently. The difference is in the pain pattern.
Kidney stones cause colicky pain that comes in waves and often radiates to the groin, while a UTI usually causes a constant burning sensation focused in the bladder, without pain that spreads to the back. B
ack strain, by contrast, worsens with movement and improves with rest, while stone pain keeps building regardless of position and does not ease with stretching. For a deeper side-by-side comparison of kidney pain versus general back pain, our related guide on kidney pain versus back pain covers positional clues in more depth.
| Feature | Kidney Stone | UTI | Back Strain |
| Pain pattern | Comes in waves | Constant burning | Worsens with movement |
| Fever | Only if infected | Common with kidney infection | Rare |
| Blood in urine | Common | Sometimes | Never |
| Eases with rest | No | Not related to rest | Yes |
When to See a Doctor
See a doctor promptly for new flank pain, even mild pain, especially if you have a family history of stones or have had one before. Go to an emergency room immediately for pain so severe you cannot sit still, pain with fever and chills, visible blood in the urine, persistent vomiting, or an inability to urinate. Recognizing the signs of kidney stones early, and knowing which ones demand urgent care, is what keeps a painful but treatable condition from turning into a kidney-threatening emergency.
FAQs
What are the very first signs of kidney stones?
Mild back or side pain, a small amount of blood in urine, and needing to urinate more often are usually the first signs before pain becomes severe.
Can kidney stones cause symptoms without pain?
Yes. Small or non-obstructing stones can cause blood in the urine or mild urinary changes with no pain at all.
Is kidney stone pain constant or does it come and go?
It comes in waves. Pain builds, peaks, and eases in cycles as the ureter spasms around the stone, unlike steady muscle pain.
How do you tell a kidney stone from a UTI?
Kidney stones cause colicky pain radiating to the groin. UTIs cause constant burning during urination without pain spreading to the back.
Sources
- Mayo Clinic: Kidney stones, Symptoms and causes link
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): Kidney Stones link
- Urology Care Foundation (American Urological Association): What Are Kidney Stones? link
- National Kidney Foundation: Kidney Stones link
- Cleveland Clinic: Kidney Stones, Causes, Symptoms, Diagnosis and Treatment link
- PMC: A comparison between asymptomatic and symptomatic ureteral stones link
- ClinicalTrials.gov: Silent Ureteral Stone, Impact on Renal Function and Kidney Anatomy link
- PMC: Urological Guidelines for Kidney Stones, Overview and Comprehensive Update link
- PMC: Systemic inflammatory response syndrome in patients with acute obstructive upper tract urinary stone link
- Mayo Clinic Health System: Kidney stones, Tiny, painful, treatable link
This article is for general information only and does not replace advice from a licensed doctor. If you think you have a kidney stone or you are in severe pain, contact a healthcare provider or go to an emergency room.
