An in-depth report on the causes, diagnosis, treatment, and prevention of urinary tract infections.
A doctor can confirm if you have a urinary tract infection by testing a sample of your urine. For some younger women who are at low risk of complications, the doctor may not order a urine test and may diagnose a urinary tract infection based on the description of symptoms.
Urinalysis. A urinalysis is an evaluation of various components of a urine sample. It involves looking at the urine color and clarity, using a special dipstick to do different chemical testing, and possibly inspecting some of the urine underneath a microscope. A urinalysis usually provides enough information for a doctor or nurse to start treatment.
Urine Culture. If necessary, the doctor may order a urine culture, which involves incubating and growing the bacteria contained in the urine. A urine culture can help identify the specific bacteria causing the infection, and determine which type of antibiotics to use for treatment. A urine culture may be ordered if the urinalysis does not show signs of infection but the doctor still suspects a UTI is causing the symptoms. It may also be ordered if the doctor suspects complications from the infection.
Clean-Catch Sample. To obtain an untainted urine sample, doctors usually request a so-called midstream, or clean-catch, urine sample. To provide this, the following steps are taken:
The sample is generally given to the doctor or sent to the laboratory for analysis.
Collection with a Catheter. Some patients (small children, elderly people, or hospitalized patients) cannot provide a urine sample. In such cases, a catheter may be inserted into the bladder to collect urine. This is the best method for providing a contaminant-free sample.
If the infection does not respond to treatment, the doctor may order other tests to determine what is causing symptoms. Imaging tests can help identify:
Ultrasound. Ultrasound is a noninvasive imaging test that can be used to screen for hydronephrosis (obstructions of the flow of urine), kidney stones that predispose to infection, and kidney abscesses. In men, ultrasound can detect enlargement or abscesses of the prostate and is an accurate method for detecting incomplete emptying of the bladder, a common cause of UTI in men over age 50. In children with urinary tract infections, it also can be used to detect vesicoureteral reflux, the defect of the valve-like mechanism between the ureter and bladder.
X-Rays. Special x-rays can be used to screen for structural abnormalities, urethral narrowing, or incomplete emptying of the bladder, which can cause stagnation of urine and predispose to infection. Due to the possible risks to the fetus, x-rays are not performed on pregnant women.
Cystoscopy. Cystoscopy is used to detect structural abnormalities, interstitial cystitis, or masses that might not show up on x-rays during an IVP. The patient is given a light anesthetic, and the bladder is filled with water. The procedure uses a cystoscope, a flexible, tube-like instrument that the urologist inserts through the urethra into the bladder.
Computed Tomography (CT). A computed tomography (CT) scans may be used to check for kidney stones or other obstructions
Blood Cultures. If symptoms are severe, the doctor will order blood cultures to determine if the infection is in the bloodstream and threatening other parts of the body.
About half of women with symptoms of a UTI actually have some other condition, such as irritation of the urethra, vaginitis, interstitial cystitis, or sexually transmitted diseases (STDs). Some of these problems may also accompany or lead to UTIs.
Vaginitis. Vaginitis is a common vaginal infection that can be caused by a fungus (candidiasis) or bacteria. Occasionally, the infection causes frequent urination, mimicking cystitis. The typical symptoms of vaginitis are itching and an abnormal discharge.
Sexually Transmitted Diseases. Women with painful urination whose urine does not exhibit signs of bacterial growth in culture may have a sexually transmitted disease. The most common microorganism is Chlamydia trachomatis. Other STDs that may be responsible include gonorrhea and genital herpes.
Interstitial Cystitis. Interstitial cystitis (IC) is an inflammation of the bladder wall that occurs almost predominantly in women. The average age of patients with IC is 40 years old, but 25% of cases occur in women under age 30. Symptoms are very similar to cystitis, but no bacteria are present. Pain during sex is a very common complaint in these patients, and stress may intensify symptoms.
Kidney Stones. The pain of kidney stones along with blood in the urine can resemble the symptoms of pyelonephritis. There are no bacteria present with a kidney stones, however.
Thinning Urethral and Vaginal Walls. After menopause, the vaginal and urethral walls become dry and fragile, causing pain and irritation that can mimic a UTI.
Disorders in Children that Mimic UTIs. Problems that might cause painful urination in children include reactions to chemicals in bubble bath, diaper rashes, and infection from the pinworm parasite.
Prostate Conditions in Men. Prostate conditions, including prostatitis (inflammation of the prostate) and benign prostatic hyperplasia, can cause symptoms similar to urinary tract infections.
Azzarone G, Liewehr S, O'Connor K. Cystitis. Pediatr Rev. 2007 Dec;28(12):474-6.
Colgan R, Nicolle LE, McGlone A, Hooton TM. Asymptomatic bacteriuria in adults. Am Fam Physician. 2006 Sep 15;74(6):985-90.
Conway PH, Cnaan A, Zaoutis T, Henry BV, Grundmeier RW, Keren R. Recurrent urinary tract infections in children: risk factors and association with prophylactic antimicrobials. JAMA. 2007 Jul 11;298(2):179-86
Faust WC, Pohl HG. Role of prophylaxis in vesicoureteral reflux. Curr Opin Urol. 2007 Jul;17(4):252-6.
Foster RT Sr. Uncomplicated urinary tract infections in women. Obstet Gynecol Clin North Am. 2008 Jun;35(2):235-48, viii.
Hodson EM, Wheeler DM, Vimalchandra D, Smith GH, Craig JC. Interventions for primary vesicoureteric reflux. Cochrane Database Syst Rev. 2007 Jul 18;(3):CD001532.
Jepson RG, Craig JC. Cranberries for preventing urinary tract infections. Cochrane Database Syst Rev. 2008 Jan 23;(1):CD001321.
Lin K, Fajardo K; U.S. Preventive Services Task Force. Screening for asymptomatic bacteriuria in adults: evidence for the U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med. 2008 Jul 1;149(1):W20-4.
Litwin MS, Saigal CS, editors. Urologic Diseases in America. US Department of Health and Human Services, Public Health Service, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases. Washington, DC: US Government Printing Office, 2007; NIH Publication No. 07-5512.
Modgil G, Baverstock A. Should bubble baths be avoided in children with urinary tract infections? Arch Dis Child. 2006 Oct;91(10):863-5.
Moore KN, Fader M, Getliffe K. Long-term bladder management by intermittent catheterisation in adults and children. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD006008.
Mori R, Lakhanpaul M, Verrier-Jones K. Diagnosis and management of urinary tract infection in children: summary of NICE guidance. BMJ. 2007 Aug 25;335(7616):395-7.
Norrby SR. Approach to the patient with urinary tract infection. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap.306.
Perrotta C, Aznar M, Mejia R, Albert X, Ng CW. Oestrogens for preventing recurrent urinary tract infection in postmenopausal women. Cochrane Database Syst Rev. 2008 Apr 16;(2):CD005131.
Peterson J, Kaul S, Khashab M, Fisher AC, Kahn JB. A double-blind, randomized comparison of levofloxacin 750 mg once-daily for five days with ciprofloxacin 400/500 mg twice-daily for 10 days for the treatment of complicated urinary tract infections and acute pyelonephritis. Urology. 2008 Jan;71(1):17-22.
Pohl A. Modes of administration of antibiotics for symptomatic severe urinary tract infections. Cochrane Database Syst Rev. 2007 Oct 17;(4):CD003237.
Roussey-Kesler G, Gadjos V, Idres N, Horen B, Ichay L, Leclair MD, et al. Antibiotic prophylaxis for the prevention of recurrent urinary tract infection in children with low grade vesicoureteral reflux: results from a prospective randomized study. J Urol. 2008 Feb;179(2):674-9; discussion 679. Epub 2007 Dec 20.
Shaikh N, Morone NE, Lopez J, Chianese J, Sangvai S, D'Amico F, Hoberman A, Wald ER. Does this child have a urinary tract infection? JAMA. 2007 Dec 26;298(24):2895-904.
U.S. Preventive Services Task Force. Screening for asymptomatic bacteriuria in adults: U.S. Preventive Services Task Force reaffirmation recommendation statement. Ann Intern Med. 2008 Jul 1;149(1):43-7. Ann Intern Med. 2008 Jul 1;149(1):W20-4.
Williams GJ, Wei L, Lee A, Craig JC. Long-term antibiotics for preventing recurrent urinary tract infection in children. Cochrane Database Syst Rev. 2006 Jul 19;3:CD001534.
© 2011 University of Maryland Medical Center (UMMC). All rights reserved.
UMMC is a member of the University of Maryland Medical System,
22 S. Greene Street, Baltimore, MD 21201. TDD: 1-800-735-2258 or 1.866.408.6885