Urinary tract infection

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Urinary tract infection
Classification & external resources
ICD-10 N39.0
ICD-9 599.0
DiseasesDB 13657
MedlinePlus 000521
eMedicine emerg/625  UTI Male
emerg/626 UTI Female

A urinary tract infection (UTI) is a bacterial infection that affects any part of the urinary tract. Although urine contains a variety of fluids, salts, and waste products, it usually does not have bacteria in it.[1] When bacteria get into the bladder or kidney and multiply in the urine, they cause a UTI. The most common type of UTI is a bladder infection which is also often called cystitis. Another kind of UTI is a kidney infection, known as pyelonephritis, and is much more serious. Although they cause discomfort, urinary tract infections are usually quickly and easily treated by seeing a doctor promptly.[2]

Contents

[edit] Symptoms & Signs

[edit] For Bladder Infections

[edit] For Kidney Infections

  • The above symptoms.
  • Emesis: Vomiting is common.
  • Back, side (flank) or groin pain.
  • Abdominal pain or pressure.
  • Shaking chills.
  • Night Sweats.
  • Extreme Fatigue.

[edit] 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. The diagnosis of UTI is confirmed by a urine culture.

If the urine culture is negative:

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.

[edit] Causative agents

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

[edit] Prevention

The following are measures that studies suggest may reduce the incidence of urinary tract infections. These may be appropriate for people, especially women, with recurrent infections:

  • 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]
  • It has been advocated that cranberry juice can decrease the incidence of UTI (some of these opinions are referenced in External Links section). 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. A review by the Cochrane Collaboration of randomized controlled trials states 'some evidence from trials to show cranberries (juice and capsules) can prevent recurrent infections in women. Many people in the trials stopped drinking the juice, suggesting it may not be a popular intervention'.[2]
  • For post-menopausal women, a randomized controlled trial has shown that intravaginal application of topical estrogen cream can prevent recurrent cystitis.[3] In this study, patients in the experimental group applied 0.5 mg of estriol vaginal cream nightly for two weeks followed by twice-weekly applications for eight months.
  • 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 preventing new infections in recurrent cases.[4][5][6] One study showed that urinary tract infection occurrence was reduced by 50% for 6 months.[7] However, this study has been criticized for several reasons.[8] Acupuncture appears to reduce the total amount of residual urine in the bladder[citation needed]. All of the studies are done by one research team without independent reproduction of results.

The following measures seem sensible, but have not been studied:[citation needed]

  • 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.
  • 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 fecal pathogens.

[edit] 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 organisms, 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 physical trauma) may physically disturb this protective lining, thereby allowing bacteria to invade the exposed epithelium.

Elderly individuals, both men and women, are more likely to harbor bacteria in their genitourinary system at any time. These bacteria may be associated with symptoms and thus require treatment with an antibiotic. The presence of bacteria in the urinary tract of older adults, without symptoms or associated consequences, is also a well recognized phenomenon which may not require antibiotics. This is usually referred to as asymptomatic bacteriuria. The overuse of antibiotics in the context of bacteriuria among the elderly is a concerning and controversial issue.

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[3].

[edit] Treatment

Most uncomplicated UTIs can be treated with oral antibiotics such as trimethoprim, cephalosporins, nitrofurantoin, or a fluoroquinolone (e.g. ciprofloxacin, levofloxacin). Whilst co-trimoxazole was previously internationally used (and continues to be used in the U.S.), the additional 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.

[edit] 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). If there is no response to treatments, interstitial cystitis may be a possibility.

During cystitis, uropathogenic Escherichia coli (UPEC) subvert innate defenses by invading superficial umbrella cells and rapidly increasing in numbers to form intracellular bacterial communities (IBCs).[9]

Researchers at Center for Genomic Sciences, Allegheny Singer Research Institute, and the Department of Microbiology and Immunology, Drexel University College of Medicine have shown that biofilms are responsible for chronic infections and, from a clinical perspective, traditional antibiotic therapy will never be a successful treatment against biofilm bacteria.[10]

[edit] References

  1. ^ Meyhoff H, Nordling J, Gammelgaard P, Vejlsgaard R (1981). "Does antibacterial ointment applied to urethral meatus in women prevent recurrent cystitis?". Scand J Urol Nephrol 15 (2): 81-3. PMID 7036332. 
  2. ^ Jepson R, Mihaljevic L, Craig J. "Cranberries for preventing urinary tract infections.". Cochrane Database Syst Rev: CD001321. PMID 14973968. 
  3. ^ Raz R, Stamm W (1993). "A controlled trial of intravaginal estriol in postmenopausal women with recurrent urinary tract infections.". N Engl J Med 329 (11): 753-6. PMID 8350884. 
  4. ^ Aune A, Alraek T, Huo L, Baerheim A (1998). "[Can acupuncture prevent cystitis in women?]". Tidsskr Nor Laegeforen 118 (9): 1370-2. PMID 9599500.  (cf acupuncture group, x2 incidents in the sham group, x3 in the control group)
  5. ^ Alraek T, Baerheim A (2001). "'An empty and happy feeling in the bladder.. .': health changes experienced by women after acupuncture for recurrent cystitis". Complement Ther Med 9 (4): 219-23. PMID 12184349. 
  6. ^ Alraek T, Baerheim A (2003). "The effect of prophylactic acupuncture treatment in women with recurrent cystitis: kidney patients fare better". J Altern Complement Med 9 (5): 651-8. PMID 14629843.  (highlights need for considering different TCM diagnostic categories in acupuncture research)
  7. ^ Alraek T, Soedal L, Fagerheim S, Digranes A, Baerheim A (2002). "Acupuncture treatment in the prevention of uncomplicated recurrent lower urinary tract infections in adult women.". Am J Public Health 92 (10): 1609-11. PMID 12356607. 
  8. ^ Katz AR (2003). "Urinary tract infections and acupuncture". Am J Public Health 93 (5): 702; author reply 702-3. PMID 12721123 (no abstract). 
  9. ^ Justice S, Hunstad D, Seed P, Hultgren S (2006). "Filamentation by Escherichia coli subverts innate defenses during urinary tract infection". Proc Natl Acad Sci U S A 103 (52): 19884-9. PMID 17172451. 
  10. ^ Ehrlich G, Hu F, Shen K, Stoodley P, Post J (Aug 2005). "Bacterial plurality as a general mechanism driving persistence in chronic infections". Clin Orthop Relat Res: 20-4. PMID 16056021. 

[edit] External links

Retrieved from "http://en.wikipedia.org../../../u/r/i/Urinary_tract_infection.html"