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
• High temperature lasting for more than 3 days should be a trigger to get the urine culture done to ascertain whether the fever is due to UTI or not. UTI is very harmful especially in infants since it can cause permanent renal damage.
• Nausea and vomiting, accompanied by high fever may indicate a more complicated UTI in which the kidney is infected
• Some urinary tract infections are asymptomatic.
• Increased confusion and associated falls are common presentations to Emergency Departments for elderly patients with UTI.

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.

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).

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.
• Practising good hygiene, including wiping from the front to the back to avoid contamination of the urinary tract by faecal pathogens.
• Cleaning the urethral meatus (the opening of the urethra) after intercourse has been shown to be of some benefit; however, whether this is done with an antiseptic or a placebo ointment (an ointment containing no active ingredient) does not appear to matter.^[1]
• 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 that cranberry juice can decrease the incidence of UTI. A specific type of tannin found only in cranberries and blueberries prevents the adherence of certain pathogens (eg. E. coli) to the epithelium of the urinary bladder (studies referenced in External Links section)

Epidemiology

UTIs are most common in sexually active women, and increase 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. The bladder wall is coated with various mannosylated proteins, such as Tamm-Horsfall proteins (THP), which interfere with the binding of bacteria to the uroepithelium. As binding is an important factor in establishing pathogenicity for these organsisms, its disruption results in reduced capacity for invasion of the tissues. Moreover, the unbound bacteria are more easily removed when voiding. The use of urinary catheters (or other physcial trauma) may physically disturb this protective lining, thereby allowing bateria to invade the exposed epithelium.

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].

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

Recurrent UTIs

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).

Often long courses of low dose antibiotics are taken at night to help prevent otherwise unexplained cases of recurring cystitis.

Acupuncture has been shown to be effective in both treating urinary tract infections, (sometimes along with chinese herbs with antibiotic compounds) as well as preventing new infections in chronic cases^{[2] [3] [4]} . A study published in October 2002 in the American Journal of Public Health showed that urinary tract infection occurrence was reduced by 50% for 6 months^[5] . Acupuncture appears to reduce the total amount of residual urine in the bladder.

If there is no response to treatments, Interstitial cystitis may be a possibility.

References

External links

• NIH articles on Urinary Tract Infections in Adults and in Children.
• The IC Community (ICC)
• Drug Watch: Cranberry juice reduces bacteriuria and pyuria
• MedlinePlus Overview urinarytractinfections
• GPnotebook -375783424