Causes

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.