tract infection

Chapter 54 Urinary tract infection




Infection of the urinary tract is a common disease. If it involves the kidneys, it can cause renal failure. Normally, the bladder and upper urinary tract are sterile, although commensal organisms are found in the distal urethra. Host defence mechanisms that keep the bladder and upper urinary tract free of infection include regular evacuation of the bladder, which helps to eliminate any organisms that gain access to the bladder lumen; tight junctions between cells of the transitional epithelium, which act as a mechanical barrier; and resident inflammatory cells in the mucosa, including plasma cells that secrete IgA.




Aetiology and pathogenesis


By far the most common route of infection is via the urethra. These ascending infections are caused by organisms derived from the patient’s own faecal commensals that gain access to the urethra. Escherichia coli is the most frequent, but any faecal organism can be responsible. Sometimes, sexually transmitted organisms such as Neisseria gonorrhoeae cause ascending infections.


Any of the factors that predispose to infection in general increase the risk of urinary tract infection (Ch. 16). There are also factors specific to the urinary tract, which will predispose to ascending infection (Fig. 3.54.1).



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Jul 3, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on tract infection

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