It’s not the stone itself that causes pain. In fact, if a stone can sit in the kidney or ureter without causing a blockage, there may be little or no pain.

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The first thing most people think about kidney stones is that passing one can be very painful. A number of factors determine if you are going to have a kidney stone. The size of the stone determines if it will make its way out of the urinary tract. Learn the symptoms of a kidney stone, the cause of kidney stone pain, what to do if you get and what you can do to prevent another stone.

Kidney Stones: Mineral Concentration

Kidney stones develop when minerals and salts in the urine become concentrated in the kidney and form pebble-like lumps, usually made of calcium and oxalate or phosphorus, A stone  may eventually move out of your kidney and travel through your  ureter, bladder, and urethra.

The ureter is the tube that drains urine from the kidney to the bladder; the urethra is the tube through which urine travels on its way out of the body. Eighty percent of stones include  calcium, but the body can also produce other types of stones, including  , uric acid, struvite, and cysteine (an amino acid that helps build protein) stones.

The most common contributing factor to kidney stones is dehydration, according to Washington University School of Medicine in St. Louis. Urine is a solution, but with dehydration, there may not be enough fluid in the urine to dilute  the minerals and salts that develop into stones.

The Cause of Kidney Stone Pain

It’s not the stone itself that causes pain. In fact, if a stone can stay in the kidney or pass through the ureter without causing a blockage, there may be little or no pain. But when a stone moves around in the kidney or gets stuck in the ureter and blocks the passage of urine, the blockage can cause the following symptoms:

• Sharp stabbing pain in the back or side
• Pain that comes and goes
• Nausea, vomiting
• Frequent urination
• Painful urination
• Blood in the urine
• Fever, but only if an infection is present

The smaller the stone, the more likely it will pass on its own. Eighty percent of kidney stones fall into that category (less than 4mm), but it takes an average of 31 days to happen. If the stone is 4-6mm, it will pass about 60 percent of the time. If greater than 6mm, the stone will pass about 20 percent of the time. In most cases where the stone is greater than 4mm, a medical procedure is necessary.

Managing the Pain

Medications include aspirin, acetaminophen, prescription pain medications, diuretics, and antibiotics. Drink plenty of fluids to increase urinary volume that may help pass the stone. Stay as active as possible. Walking helps. Your doctor may prescribe a drug that relaxes the ureter, which allows the stone to pass. Taking a hot shower or sitting in a tub of warm water offers temporary relief.

When to See a Doctor for Kidney Stones

Notify your doctor if you think you have a kidney stone. If you have severe pain and other signs and symptoms of a stone, get help right away. Your healthcare provider may recommend some of the measures above, and may ask you to capture a stone if it passes so it can be analyzed.

Blood tests can show calcium levels, glandular problems, and kidney dysfunction. A CT scan can identify a kidney stone, and ultrasound scans detect swelling of the kidney and/or the ureter—an indication that the stone is blocking the flow of urine.

Under the supervision of a doctor, you might be able to treat a kidney stone at home. If the stone is too large, the pain too severe, infection is present, or there is significant bleeding, the kidney stone will have to be removed surgically or broken into fragments that can move through the urinary tract.

Prevention

About half the people who have a kidney stone will never have another incident. For those who have recurring stones, the prognosis depends on the cause and on how well the patient responds to prevention guidelines. They include drinking more fluids, eating less protein, reducing the intake of salt, and increasing the intake of citrate (lemons, oranges, grapefruit), a chemical that inhibits the production of kidney stones.

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This article was originally published in 2018. It is regularly updated.