ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

A General Overview, Etiology And Pathogenesis Of Urinary Tract Infections

Updated on February 6, 2014

Urinary Tract Infections

What Are The Signs And Symptoms Of Urinary Tract Infection?
What Are The Signs And Symptoms Of Urinary Tract Infection?

Etiology And Pathogenesis

The urinary tract is a common site for bacterial infections in humans. Women i=of child-breaing age are affected more. About 20% of all women develop urinary tract infection at sometime or other in their lives.

The term acute ‘pyelonephritis’ refers to acute inflammation of the kidney and its pelvis. In chronic pyelonephritis, there is inflammation of pelvis and calyces with fibrosis and deformity of renal parenchyma. Infection limited to the bladder is termed “cystitis”. Presence of more than 100,000 (105) pathogenic bacterial/ml of urine is ‘significant bacteriuria’. Sometimes significant bacteriuria may exist without producing symptoms- “asymptomatic bacteriuria”. Reflux nephropathy denotes the renal involvement which occurs as a result of vesico-ureteric reflux. Vesico-uretheric reflux is frequently caused or accompanied by bacterial infection.

Etiology: The organisms associated with urinary tract infection are those found most frequently in the gastrointestinal tract or in the vaginal vestibule. Approximately 80-85% are caused by Escherichia coli (E.Coli). Proteus, Klebsiella and Enterobacter species are relatively more common in hospital- acquired infections. Other organisms include Streptococcus fecalis, Pseudomonas aeruginosa and some species of Candida. The urine is strongly acidic in E.Coli infection. In Proteus infection, the urine is highly alkaline as a result of conversion of urea into ammonia in the urinary tract.

Pathogenesis: In many women there is a tendency for colonization of the organisms in the introitus. On account of the shortness of the urethra and tendency to produce lower urinary tract obstruction during pregnancy, women suffer more. Sexual intercourse serves to precipitate infection in predisposed individuals. Bacteria gain access to the urethral meatus from the anorectal regions and they ascend through the urethra or periurethral tissue into the bladder, ureters, renal pelvis, and parenchyma. Structural abnormalities of the urinary tract, obstructive lesions, presence of foreign bodies such as calculi or catherters, vesico-ureteric reflux, pregnancy and diabetes mellitus predispose to urinary infection.

Vesico-ureteric reflux is the pathological condition in which urine from the bladder regurgitates into the ureter and ascend to the Kidney during the process of micturition. Urinary tract infection is a common complication of vesico-ureteric reflux. A combincation of factors such as the back pressure transmitted from the bladed and persistence of infection leads to renal acarring and chronic interstitial nephritis.

Host defence against bacteria depends on the integrity of the phagocytes and the immune system. Local protective factors are the constant downward flow of urine and periodic evacuation of the bladder, the pH of urine, and prostatic secretions in males. Hematogenous infection of the urinary tract, through relatively rare, may occur as part of septicemia or in immunosuppressed hosts.

Urinary Tract Infections



In acute pyelonephritis, the kidneys are enlarged and contain several small abscesses. Areas of inflammation may be seen. With very severe infection, the bases of renal papillae may undergo necrosis and detached fragments may be passed in urine. These may cause acute ureteric obstruction or even reflex anuria. Histologically, the interstitium shows edema and patchy infiltration by polymorphonuclear leucocytes. The glomeruli are relatively normal.

In chronic pyelonephritis, the kidneys are often smaller than normal and their surfaces showing scarring. The renal calyces may show abnormalities on account of scarring. The corticomedullary junction may be indistinct and the renal cortex itself may be thinned out. Histological features are tubular damage, infiltration of the interstitium with chronic inflammatory cells, fibrosis and scarring. Glomeruli may show areas of focal sclerosis.

© 2014 Funom Theophilus Makama


    0 of 8192 characters used
    Post Comment

    No comments yet.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)