Diagnosing Urinary Tract Infections

Urinary tract infection (UTI) is the second most common type of infection, leading to millions of doctor visits per year in the United States. Doctors at NYU Langone are skilled in diagnosing and treating UTI in both men and women.

The urinary tract consists of the kidneys, which filter waste from the blood and produce urine; the ureters, which carry urine from the kidneys to the bladder; the bladder, which stores it; and the urethra, which carries urine out of the body. A UTI can occur at any point along this tract.

Women are more prone to UTIs than men because a woman’s urethra is shorter and closer to the anus. This makes it easier for bacteria from the bowel to enter the bladder.

UTIs are also common in children, accounting for up to 1 million pediatrician visits each year, and in older adults.

UTIs are typically caused by bacteria around the urethra, in the vagina, or in the bowel. Sexual activity can cause bacteria, such as Escherichia coli, or E. coli, to enter the urethral opening, particularly in women. UTIs can also be caused by certain bacteria that are present in the urethra and the reproductive system.

Symptoms of a UTI can include a strong urge to urinate, burning with urination, passing small amounts of urine, or urine that is cloudy, red, pink, brown, or strong-smelling. Other symptoms may include pain in the pelvis, rectum, or under the ribs; chills, fever, nausea, and vomiting. Left untreated, the infection can lead to a life-threatening kidney condition. However, when a UTI doesn’t cause any symptoms, it may not require treatment.

A person’s risk of developing a UTI is higher if he or she uses a urinary catheter. The use of certain forms of birth control, such as a diaphragm, can increase risk in women. People with conditions that affect the immune system, such as diabetes, and those with kidney stones or benign prostatic hyperplasia, also have a higher risk of a UTI. Kidney stones or an enlarged prostate can prevent the bladder from emptying completely, which may encourage bacteria.

Pregnant women have a higher risk of UTI because pregnancy hormones cause changes in the urinary tract that increase susceptibility to infection. Because UTIs can cause bacteria to travel to the kidneys, which can lead to a life-threatening condition called septicemia, your NYU Langone obstetrician–gynecologist routinely tests your urine for bacteria throughout pregnancy.

To diagnose a UTI, your NYU Langone doctor asks about your medical history, performs a physical exam, and may recommend one or more tests.

Urinalysis

You are given a sterile container for a “clean catch” urine sample. This is performed by first washing the genital area with a supplied antiseptic wipe. Women should wipe from front to back and men should clean the urethral opening on the penis. You begin urinating in the toilet, stop midstream, and then collect the remaining urine in the container. This method helps prevent bacteria on the genitals from affecting test results.

This urine sample is tested for bacteria in the doctor’s office. A positive result indicates a high likelihood of infection. In that case, the specimen is examined for specific bacteria in a laboratory. If you are experiencing symptoms and the initial test results are positive, your doctor may prescribe medication at that time.

Home test kits for UTI can be purchased at a local pharmacy without a prescription. These typically include treated plastic strips, or dipsticks, that you hold in your urine stream or dip into a urine sample in a supplied container. If your urine tests positive for a bacterial infection, an area on the dipstick changes color. If the test results indicate you may have a UTI, contact your doctor for treatment.

Ultrasound

If you have frequent urinary tract infections, your doctor may order an ultrasound to check the kidneys and bladder for irregularities that may require treatment. This test uses sound waves to create images of structures inside the body. The doctor or technician places a device called a transducer on the abdomen, which transmits images to a computer monitor.

CT Scans

Your doctor may perform a CT scan to provide clear, three-dimensional images of the urinary tract. This test can help in detecting infections, stones, cysts, or tumors.

In a CT scan, a series of X-rays of the urinary tract is taken and images are sent to a computer monitor for review.

Cystoscopy

Sometimes a cystoscopy is performed to diagnose the cause of a recurrent UTI. It can help the doctor look inside the bladder for signs of infection, including irritation. Cystoscopy can also help doctors identify causes of symptoms or infection, such as stones, obstructions, or lesions in the bladder.

During this test, the doctor guides a narrow, flexible scope through the urethra into the bladder and injects a sterile solution to fill the bladder. This procedure is performed in the doctor’s office using a local anesthetic.