Urinary tract infection: Encyclopedia - Urinary tract infection

Urinary tract infection

A urinary tract infection (UTI) is an infection of the urinary tract. An infection anywhere from the kidneys to the ureters to the bladder to the urethra qualifies as a urinary tract infection.

Urinary tract infection - Symptoms & Signs

• Urethritis: discomfort or pain at the urethral meatus or a burning sensation throughout the urethra with micturition (dysuria).
• Cystitis: pain in the midline suprapubic region and/or frequent urination
• Hematuria (bloody urine)
• cloudy and foul-smelling urine

Urinary tract infection - Diagnosis

A patient with dysuria (painful voiding) and urinary frequency generally has a spot mid-stream urine sample sent for urinalysis, specifically the presence of nitrites, leukocytes or leukocyte esterase. If there is a high bacterial load without the presence of leukocytes, it is most likely due to contamination. Pyelonephritis is ruled out by checking for costovertebral angle tenderness (CVAT). The diagnosis of UTI is confirmed by a urine culture.

If the urine culture is negative:

• symptoms of urethritis may point at Chlamydia trachomatis or Neisseria gonorrheae infection.
• symptoms of cystitis, may point at interstitial cystitis.
• in men, prostatitis may present with dysuria.

In severe infection, characterised by fever, rigors or flank pain, urea and creatinine measurements may be performed to assess whether renal function has been affected.

Urinary tract infection - Causative agents

Common organisms that cause UTIs include: Escherichia coli and Staphylococcus saprophyticus. Less common organisms include Proteus mirabilis, Klebsiella pneumoniae, and Enterococcus spp.

A mnemonic that can be used to remember the bacteria that cause UTIs is SEEK PP (Staph saprophyticus, E. coli, Enterococcus, Klebsiella, Proteus, Pseudomonas).

Urinary tract infection - Prevention

The following are a list of things that can be done to avoid a urinary tract infection. As many people, especially women, experience recurrent infections some commonly recommended preventative measures are

• Having adequate fluid intake, especially water.
• Not resisting the urge to urinate.
• Taking showers, not baths, or urinating soon after taking a bath.
• Practicing good hygiene, including wiping from the front to the back to avoid contamination of the urinary tract by faecal pathogens.
• Cleaning genital areas prior to and after sexual intercourse.
• For sexually active women, and to a lesser extent men, urinating within 15 minutes of sexual intercourse to allow the flow of urine to expel the bacteria before specialized extensions anchor the bacteria to the walls of the urethra.
• It has been advocated by some, that cranberry-juice would decrease the incidence of UTI, by acting as a urinary antiseptic.

Urinary tract infection - Epidemiology

UTIs are most common in sexually active women, and increased in diabetics and people with sickle-cell disease or anatomical malformations of the urinary tract.

The use of urinary catheters in both men and women who are elderly, people experiencing nervous system disorders and people who are convalescing or unconscious for long periods of time may result in an increased risk of urinary tract infection for a variety of reasons. Scrupulous aseptic technique may decrease this risk.

Women are more prone to UTIs than males because in females, the urethra is much shorter and closer to the anus than in males. The article on vulvovaginal health has some health tips for preventing UTIs.

A common cause of UTI is an increase in sexual activity, such as vigorous sexual intercourse with a new partner. The term "honeymoon cystitis", although somewhat demeaning, has been applied to this phenomenon[1].

Urinary tract infection - Treatment

Most uncomplicated UTIs can be treated with oral antibiotics such as trimethoprim, cephalosporins, Macrodantin, or a fluoroquinolone (e.g. ciprofloxacin, levofloxacin). (Whilst co-trimoxazole was previously used (and continues to be used in the U.S.), the additional benefits of the sulphonamide gave little additonal benefit compared to the trimethoprim component alone, but was responsible for its both high incidence of mild allergic reactions and rare but serious complications).

If patient has symptoms consistent with pyelonephritis, intravenous antibiotics may be indicated.

Patients with recurrent UTIs may need further investigation. This may include ultrasound scans of the kidneys and bladder or intravenous urography (X-rays of the urological system following intravenous injection of iodinated contrast material).

Adapted from the Wikipedia article "Urinary tract infection", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki