Bladder stones are small masses of minerals that form in your bladder. Bladder stones develop when urine in your bladder becomes concentrated, causing minerals in your urine to crystallize. Concentrated, stagnant urine is often the result of an enlarged prostate, nerve damage or recurring urinary tract infections.

Bladder stones don't always cause signs or symptoms and are sometimes discovered during tests for other problems. When symptoms do occur, they can range from abdominal pain to blood in your urine.

Small bladder stones sometimes pass on their own, but you may need to have others removed by your doctor. Left untreated, bladder stones can cause infections and other complications.

Some people with bladder stones have no problems — even when their stones are large. But if a stone irritates the bladder wall or blocks the flow of urine, signs and symptoms can develop. These include:

• Lower abdominal pain
• In men, pain or discomfort in the penis
• Painful urination
• Frequent urination, especially during the night
• Difficulty urinating or interruption of urine flow
• Urine leakage (incontinence)
• Blood in your urine
• Abnormally dark-colored urine

Bladder stones come in a variety of characteristics:

• They can be small, or large enough to fill your entire bladder.
• They can be soft or hard.
• They can be smooth, or jagged and spiked.
• You can have a single bladder stone or several.

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Male urinary system

Your kidneys filter your blood, absorbing substances your body needs and removing excess liquid and waste, which is excreted as urine. The urine leaves your kidneys through two slender tubes (ureters) and enters your bladder, where it's stored until it passes out of your body.

If your bladder doesn't empty completely, the retained urine can begin to form crystals that eventually become bladder stones. In most cases, an underlying condition affects your bladder's ability to empty completely. The most common of these conditions include:

• Prostate gland enlargement. An enlarged prostate, or benign prostatic hyperplasia (BPH), is one of the most common causes of bladder stones in men. As the prostate enlarges, it can compress the urethra and interrupt urine flow, causing urine to remain in your bladder.
• Neurogenic bladder. Normally, nerves carry messages from your brain to your bladder muscles, directing your bladder muscles to tighten or release. If these nerves are damaged — from a stroke, spinal cord injury or other health problem — your bladder may not empty completely.
• Bladder diverticula. These are weakened areas in the bladder wall that bulge outward in pouches. Bladder diverticula may be present at birth or develop later as a result of benign prostatic hyperplasia or other conditions that cause poor bladder drainage.

Other conditions that can cause bladder stones include:

• Inflammation. Bladder stones can develop if your bladder becomes inflamed. Urinary tract infections and radiation therapy to your pelvic area can both cause bladder inflammation.
• Medical devices. Occasionally, catheters — slender tubes inserted through the urethra to help urine drain from your bladder — can cause bladder stones. So can objects that accidentally migrate to your bladder, such as a contraceptive device or stent. Mineral crystals, which later become stones, tend to form on the surface of these devices.
• Kidney stones. Stones that form in your kidneys are not the same as bladder stones — they develop in different ways and often for different reasons. But small kidney stones occasionally travel down the ureters into your bladder and if not expelled, can grow into bladder stones.

In developing nations, bladder stones are common in children — often because of dehydration and a low-protein diet — but in other parts of the world, bladder stones occur primarily in older men. If you live in an industrialized country, these factors increase your risk:

• Your sex. Bladder stones occur primarily in men.
• Your age. In wealthy countries, bladder stones tend to occur in people age 50 and older, although younger men who have urinary retention may also develop stones.
• Bladder outlet obstruction. The most common cause of bladder stones in men, bladder outlet obstruction refers to any condition that blocks the flow of urine from your bladder to the urethra, the tube that carries urine out of your body. Bladder outlet obstruction has many causes, but the most common is an enlarged prostate. Other possible causes include prostate cancer, narrowing of the urethra from infection or surgery — even certain medications.
• Neurogenic bladder. Stroke, spinal cord injuries, Parkinson's disease, diabetes, a herniated disk and a number of other problems can damage the nerves that control bladder function. Some people with neurogenic bladder may also have an enlarged prostate or other type of bladder outlet obstruction, which further increases the risk of stones.
• Frequent bladder infections. Inflammation from chronic bladder infections can lead to the formation of bladder stones.

Bladder stones that aren't removed — even those that don't cause symptoms — can lead to complications, such as:

• Chronic bladder dysfunction. Left untreated, bladder stones can cause long-term urinary problems, such as pain or frequent urination. Bladder stones can also lodge in the opening where urine exits the bladder into the urethra, and block the passage of urine from your body.
• Urinary tract infections. Recurring bacterial infections in your urinary tract may be caused by bladder stones.
• Bladder cancer. Chemicals or objects that cause chronic irritation of the bladder wall, including bladder stones, increase your risk of bladder cancer.

You're likely to have one or more tests to help diagnose bladder stones. Be sure to ask your doctor whether you need to avoid eating, drinking or taking certain medications before the test. You might also find it helpful to prepare a list of other questions for your doctor, such as:

• Do bladder stones pass on their own?
• If not, should they be removed and what is the best method?
• What are the risks of the treatment you're proposing?
• What will happen if the stones aren't removed?
• Is there any medication I can take to eliminate bladder stones?
• How can I keep them from coming back?

Making a diagnosis of bladder stones begins with a physical exam. Your doctor will likely feel your lower abdomen to see if your bladder is distended and, in some cases, perform a rectal exam to determine whether your prostate is enlarged. You may also discuss any urinary signs or symptoms that you've been having.

Other tests used to make a diagnosis of bladder stones may include:

• Urinalysis. A sample of your urine may be collected and examined for microscopic amounts of blood, bacteria and crystallized minerals. A urinalysis is also helpful for determining whether you have a urinary tract infection, which can cause bladder stones.
• Cystoscopy. During cystoscopy, your doctor inserts a tube with a small camera at the end (cystoscope) through your urethra and into your bladder. After the cystoscope is in place, your doctor fills the cystoscope with water, which flows into your bladder. As fluid fills your bladder, it stretches the bladder wall, allowing your doctor to view the bladder interior. Cystoscopy is the most sensitive test for diagnosing bladder stones because it helps your doctor see the number, size and location of the stones in your bladder.
• Spiral computerized tomography (CT) scan. A conventional CT scan combines multiple X-rays with computer technology to create cross-sectional images of your body rather than the overlapping images produced by regular X-rays. A spiral CT speeds up this process, scanning more quickly and with greater definition of internal structures. Spiral CTs can detect even very small stones and are considered one of the most sensitive tests for identifying bladder stones of all types.
• Ultrasound. An ultrasound, which bounces sound waves off organs and structures in your body to create pictures, can help your doctor visualize bladder stones.
• X-ray. An X-ray of your kidneys, ureters and bladder helps your doctor determine whether stones are present in your urinary system. This is an inexpensive and easy test to obtain, but some types of stones aren't visible on conventional X-rays.
• Intravenous pyelogram. An intravenous pyelogram is a test that uses a contrast material to visualize organs in your urinary tract. The material is injected into a vein in your arm and flows into your kidneys, ureters and bladder, outlining each of these organs. X-ray pictures are taken at specific time points during the procedure to check for stones. In many cases, helical CT scans have now replaced this test.

Most bladder stones should be removed. If the stone is small, your doctor may recommend that you drink an increased amount of water each day to help the stone pass. If the stone is large or doesn't pass on its own, your doctor may need to remove the stone.

Breaking stones apart
Bladder stones are often removed during a procedure called a cystolitholapaxy. A small tube with a camera at the end (cystoscope) is inserted through your urethra and into your bladder to view the stone. Your doctor then uses a laser, ultrasound or mechanical device to break the stone into small pieces and flushes the pieces from your bladder.

You'll likely have regional or general anesthesia prior to the procedure to make you comfortable. Complications from a cystolitholapaxy aren't common, but urinary tract infections, fever, a tear in your bladder and bleeding can occur. Your doctor may give you antibiotics before the procedure to reduce the risk of infections. About a month after the cystolitholapaxy, your doctor will likely check to make sure that no stone fragments remain in your bladder.

Occasionally, bladder stones that are large or too hard to fragment are removed through open surgery. In these cases, your doctor makes an incision in your bladder and directly removes the stones. Any underlying condition causing the stones, such as an enlarged prostate, may be corrected at the same time.

For centuries, some people have tried to use herbs to treat and prevent stones that form in the kidneys and bladder. Traditional herbs for bladder stones include gravel root (also called kidney root, queen of the meadow and Joe Pye), stone root (also called citronella and colinsonia) and hydrangea (wild or mountain hydrangea).

These herbs are used alone or in various combinations and drunk as tea or taken in tincture form. Some herbal formulas add marshmallow, which is said to coat the fragments so that they can be eliminated painlessly. No studies, however, have confirmed that herbs can break up bladder stones, which are extremely hard and usually require a laser, ultrasound or other procedure for removal.

Bladder stones usually result from an underlying condition that's hard to prevent, but you can decrease your chance of developing bladder stones by following these tips:

• Ask about unusual urinary symptoms. Early diagnosis and treatment of an enlarged prostate or another urological condition may reduce your risk of developing bladder stones.
• Drink plenty of fluids. Drinking lots of fluids, especially water, may help prevent bladder stones because fluids dilute the concentration of minerals in your bladder. How much water you should drink depends on your age, size, health and level of activity. Ask your doctor what's an appropriate amount of fluid for you.
• Try cranberry juice. Chronic bladder infections can lead to the formation of bladder stones. Cranberry juice may help prevent these infections by slowing bacterial growth and preventing bacteria from adhering to the lining of your bladder.