What is an urolith?

What is a urolith? The answer is a urinary tract stone.

A urolith is a mineral deposit or calculus that forms within the urinary system. The urinary tract includes the kidneys, ureters, bladder, and urethra, so a urolith is not restricted to the bladder.

Uroliths develop when dissolved substances in urine become concentrated and crystallize. The resulting stones may contain compounds such as calcium oxalate, uric acid, struvite, or cystine. Their size and composition vary widely.

When stones remain in the kidney, the condition is commonly called nephrolithiasis. Urolithiasis is the broader term for urinary stones, including stones that form elsewhere in the urinary tract. Because the terms are sometimes used loosely, “kidney stone” may refer to urinary stones generally, but it is narrower than “urolith.”

Uroliths can cause pain, blood in the urine, difficult urination, infection, or obstruction, depending on their location and size. A bladder stone is one possible type of urolith, not the complete definition.