Kidney Stone Pain: What Does It Feel Like and When Is It Urgent?

Kidney stone pain often feels like a sharp, cramping ache in the side or back that comes in waves and may spread toward the lower abdomen and groin. It can arrive suddenly and be severe enough to cause nausea and restlessness. Pain with fever and chills, an inability to pass urine, or fainting needs emergency care. This article describes the pain pattern, related symptoms, and which signs call for urgent evaluation.

What kidney stone pain feels like

A kidney stone is a hard deposit of minerals and salts that forms in the kidney. According to MedlinePlus, a stone may cause no symptoms while it stays in the kidney. Pain often begins when a stone moves into the ureter, the narrow tube that carries urine from the kidney to the bladder.

People commonly describe the pain as sharp, stabbing or cramping. It is often felt in the flank (the side of the body between the ribs and the hip) and the back, and it may be on only one side. Many people find they cannot get comfortable and keep shifting position, which differs from pain that eases when you lie still.

Why the pain comes in waves

The ureter squeezes in rhythmic contractions to push urine along. When a stone blocks or irritates it, urine can back up and the tube can spasm. Several factors probably contribute to the intensity, including the stone's size and position and how much the kidney swells. The exact mechanism is not fully understood, and stone size does not always match how bad the pain is. A small stone can hurt a great deal, and a larger stone in the kidney may cause little.

Where the pain travels

As a stone moves down the ureter, the pain can shift. It may start in the back or side under the ribs, then move toward the lower abdomen and groin. In men it can sometimes be felt in the testicle, and in women in the labia. Pain near the bladder may come with an urge to urinate often or a burning feeling, which can resemble a urinary infection. If burning is your main symptom and a urine test for infection is negative, our article on burning with a negative UTI test covers other explanations.

Other symptoms that can come with a stone

• Nausea and vomiting. These are common, partly because the kidneys and the digestive tract share nerve pathways.
• Blood in the urine. Urine may look pink, red or brown. Sometimes blood is only visible under a microscope. Blood in the urine has several possible causes, discussed in our article on painless blood in urine.
• Cloudy or strong-smelling urine. This may suggest infection along with a stone.
• Frequent urge to urinate or passing small amounts.
• Fever and chills. These can suggest that a blocked kidney is also infected, which is an emergency.

Why a blocked, infected kidney is the main danger

Most stones are painful but pass without lasting harm. The serious situation is a stone that blocks urine flow while infection is present. Trapped, infected urine can spread to the bloodstream and become life-threatening, and a blocked kidney can be damaged if the blockage continues. Fever with flank pain, shaking chills, confusion, a racing heart, or feeling severely ill requires emergency evaluation. A person with only one working kidney, or with kidney disease, should treat a blockage with extra concern because there is less reserve.

Other causes of side and back pain

Not every sharp flank pain is a stone. Clinicians combine your history, an examination, urine tests and often imaging to sort out the cause. Other possibilities include a kidney or bladder infection, muscle strain, and problems in the abdomen. Some of these are serious, such as appendicitis, a twisted ovary or testicle, and an ectopic pregnancy in someone who could be pregnant. For a wider list, see causes of abdominal pain and causes of lower back pain. Severe sudden pain in the groin or testicle, or abdominal pain with a missed period, needs prompt evaluation whether or not you suspect a stone.

How clinicians evaluate suspected stones

A clinician will usually ask about the pain pattern, previous stones, fluid intake, and family history. A urine test can look for blood and signs of infection, and blood tests can check kidney function (see MedlinePlus on kidney tests). Imaging, such as a CT scan or ultrasound, may be used to find a stone and see whether urine is backing up. Which test is chosen depends on your situation, including pregnancy.

What happens next

Many smaller stones pass on their own, and care often focuses on pain control and monitoring. Your clinician may discuss pain medicines, and may prescribe a medicine to help the stone pass or recommend a procedure if the stone is large, will not pass, or causes a blockage or infection. Pain relievers such as ibuprofen carry label cautions, including for people with kidney disease, stomach ulcers, or those taking blood thinners, so ask your clinician or pharmacist what is safe for you. Do not change prescription doses on your own.

Drinking fluids is commonly advised, but forcing large amounts while in severe pain with vomiting is not a substitute for evaluation. If you cannot keep fluids down, you need to be seen.

Reducing the chance of another stone

MedlinePlus notes that stones can recur. Prevention depends on the stone type, which your clinician may identify by analyzing a passed stone. Strategies may include drinking enough fluid, adjusting salt and certain foods, and sometimes medicine. Some stones are related to other conditions, such as gout, which is explained on MedlinePlus's gout page. Strain any urine through a filter if your clinician asks so the stone can be caught and tested.

Making sense of your pain

Write down when the pain started, where it moves, whether it comes in waves, and any fever, vomiting or changes in urine. This helps a clinician decide how quickly you need to be seen. For a general overview, read MedlinePlus on kidney stones.

When to Seek Medical Care