an inflammatory reaction of the urinary tract epithelium in response to pathogenic micro-organisms

Urinary tract - normally sterile but can become colonised

Most common causative organisms:

• E. coli
• Proteus miribalis (can be associated with stones)
• Klebsiella

Host risk factors for UTIs

Gender: far more common in women

Extremes of age : younger children & older adults (post-menopausal ♀)

Compromised barriers to infection : Physical (anatomical) :

• Shorter ♀ urethra (especially if sexually active or post-menopausal)
• Malformations (PKD, renal & ureteric malformations, strictures)
• Internal obstructions (stones or tumours)
• Bladder outflow obstruction (pregnancy, prostate enlargement)
• Iatrogenic (urinary catheters, operations, post-operative changes) Catheters are a key source of infection, catheter associated infections tend to be more significant and difficult to treat.

Immunocompromised host: UTI more common with diabetes mellitus

PC:

Lower UTI:

• Dysuria