Sometimes bladder stones — even large ones — cause no problems. But if a stone irritates the bladder wall or blocks the flow of urine, signs and symptoms may include:

• Lower abdominal pain
• Pain during urination
• Frequent urination
• Difficulty urinating or interrupted urine flow
• Blood in the urine
• Cloudy or unusually dark-colored urine

Bladder stones can develop when your bladder doesn't empty completely. This causes urine to become concentrated urine. Concentrated urine can crystallize and form stones.

Some infections can lead to bladder stones. Sometimes an underlying condition that affects the bladder's ability to hold, store or eliminate urine can result in bladder stone formation. Any foreign materials present in the bladder tend to cause bladder stones.

The most common conditions that cause bladder stones include:

• Prostate gland enlargement. An enlarged prostate (benign prostatic hyperplasia, or BPH) can cause bladder stones in men. An enlarged prostate can obstruct the flow of urine, preventing the bladder from emptying completely.
• Damaged nerves. 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. This is known as neurogenic bladder.

Other possible causes of bladder stones include:

• Inflammation. Bladder inflammation, sometimes caused by urinary tract infections or radiation therapy to the pelvis, can lead to bladder stones.
• Medical devices. Bladder catheters — slender tubes inserted through the urethra to help urine drain from your bladder — may cause bladder stones. So can objects that accidentally migrate to your bladder, such as a contraceptive device or urinary stent. Mineral crystals, which later become stones, tend to form on the surfaces of these devices.
• Kidney stones. Stones that form in your kidneys are not the same as bladder stones. They develop in different ways. But small kidney stones may travel down the ureters into your bladder and, if not expelled, can grow into bladder stones.

Men, especially those over 50, are more likely to have bladder stones.

Conditions that can raise the risk of bladder stones include:

• An obstruction. Any condition that blocks the flow of urine from your bladder to the urethra — the tube that carries urine out of your body — can lead to bladder stone formation. There are a number of causes, but the most common is an enlarged prostate.
• Nerve damage. Stroke, spinal cord injuries, Parkinson's disease, diabetes, a herniated disk and a number of other problems can damage nerves that control bladder function.

It's possible to have nerve damage and a condition that causes bladder outlet obstruction. Having these together further increases the risk of stones.

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

• Chronic bladder problems. Untreated bladder stones can cause long-term urinary difficulties, 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 flow of urine.
• Urinary tract infections. Repeated bacterial infections in your urinary tract may be caused by bladder stones.

Bladder stones are usually caused by an underlying condition that's hard to prevent, but you can decrease your chances of bladder stones by following these tips:

• Tell your doctor about unusual urinary symptoms. Early diagnosis and treatment of an enlarged prostate or another urologic condition may reduce your risk of developing bladder stones.
• Drink plenty of fluids. Drinking more 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.

Diagnosing bladder stones may involve:

• A physical exam. Your doctor will likely feel your lower abdomen to see if your bladder is enlarged (distended) or may perform a rectal exam to determine whether your prostate is enlarged. You'll also discuss any urinary signs or symptoms that you're having.
• A urine test. A sample of your urine may be collected and examined for microscopic amounts of blood, bacteria and crystallized minerals. A urine test also looks for a urinary tract infection, which can cause or be the result of bladder stones.
• CT scan. CT uses X-rays and computers to quickly scan and provide clear images of the inside of your body. CT can detect even very small stones. It's one of the most-sensitive tests for identifying all types of bladder stones.
• Ultrasound. This test bounces sound waves off organs and other structures in your body to create images that help detect bladder stones.
• X-ray. An X-ray of your kidneys, ureters and bladder helps your doctor determine whether you have bladder stones. Some types of stones can't be seen on conventional X-rays, however.

Drinking lots of water may help a small stone pass naturally. However, because bladder stones are often caused by difficulty emptying your bladder completely, extra water may not be enough to make the stone pass.

Most of the time, you'll need to have the stones removed. There are a few ways to do this.

Breaking stones apart

In one method, you're first given numbing medication or general anesthesia to make you unconscious. After that, a small tube with a camera at the end is inserted into your bladder to let your doctor see the stone. Then, a laser, ultrasound or other device breaks the stone into small pieces and flushes them from the bladder.

Surgical removal

Occasionally, bladder stones are large or too hard to break up. In these cases, your doctor will surgically remove the stones from your bladder.

If your bladder stones are the result of a bladder outlet obstruction or an enlarged prostate, these problems need to be treated at the same time as your bladder stones, typically with surgery.

There's no evidence that herbal remedies can break up bladder stones. These stones are extremely hard and usually require a laser, ultrasound or other procedure for removal. Always check with your doctor before taking any alternative medicine therapy to be sure it's safe and that it won't cause any problems with other medications you're taking.

If you have signs and symptoms of bladder stones, you're likely to see your primary care doctor first. You may then be referred to a doctor who specializes in treating urinary tract disorders (urologist).

What you can do

To get ready for your appointment, make a list of:

• Any symptoms you're experiencing, including any that may seem unrelated to your condition
• Key personal information, including any major stresses or recent life changes
• All medications you're taking, as well as any vitamins or supplements

In addition:

• Be aware of any pre-appointment restrictions. Ask if there's anything you need to do in advance, such as restrict your diet.
• Ask a family member or friend to come with you. Someone who accompanies you may remember information that you missed or forgot.

It's also a good idea to make a list of questions for your doctor. For bladder stones, some basic questions to ask include:

• Is it possible my bladder stones could pass without treatment?
• If not, do they need to be removed, and what's 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?
• I have other health conditions. How can I best manage these conditions together?
• Are there any dietary restrictions that I need to follow?
• Will the stones come back?
• Do you have any printed materials that I can have? What websites do you recommend?

Don't hesitate to ask additional questions that may come up during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, such as:

• When did you begin experiencing symptoms?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• Have you had a fever or chills?
• Does anything seem to improve your symptoms?
• Does anything make your symptoms worse?