Causes of White Blood Cells in Urine

Conditions affecting your urinary tract can make daily tasks uncomfortable. Urine is normally sterile and does not contain blood cells. The presence of white blood cells -- WBCs -- in a urine sample indicates an abnormal condition within the urinary tract or kidney. The kidney, bladder and other parts of the urinary tract may become inflamed or infected.

Urinary Tract Infection

A urinary tract infection -- UTI -- is a common cause of WBCs in urine. Bacteria enter the urethra and travel up to the bladder, causing cystitis -- an infection of the bladder 2. Women have shorter urethras than men, making women more prone to these infections. In men, infection may start in the prostate and move up into the bladder, causing cystitis. Symptoms of UTI include urinary frequency, bladder spasms, urgency to urinate every few minutes and pain just above the pubic bone. Antibiotics are typically used to treat UTIs.

Interstitial Cystitis

Unlike UTI, interstitial cystitis is not caused by infection. White blood cells in the urine are caused by inflammation of the bladder wall. IC is more common in women than men, and causes urinary urgency, frequency and pelvic pain. This condition is treated with oral medications to protect the mucous lining of the bladder, reduce inflammation, adjust hormone levels and reduce pain. If conservative treatment is not successful, surgery may be required.

Pyelonephritis

Pyelonephritis -- infection of the kidney -- can cause WBCs in your urine. Symptoms of pyelonephritis may include severe pain, fever, malaise, nausea and vomiting. This condition is caused by bacterial or viral infections, and is typically treated with antibiotics. Pyelonephritis affects people of all ages, but is more common in women.

Kidney Stones

Kidney stones impede the passage of urine in the urethra. As a result, urine stagnates, increasing risk of bacterial infection. Irritation of the urethra from these stones may also cause WBCs in your urine. Kidney stones cause severe pain that may come in waves, making it difficult for you to stay in one position. If the stone is blocking the urethra, it may be difficult to urinate or you may urinate only small amounts at a time. Bladder spasms and pain during urination may also occur. People who have had one kidney stone are more likely to have more. If the stones are too large to pass through your urinary tract, they can be broken up with ultrasound or surgically removed.