24. Urinary tract infections
Urinary tract infections (UTI) are more common at certain ages (Fig. 3.24.1). While many infections are mild, renal infections may lead to long-term kidney damage, and the urinary tract is a common source of life-threatening Gram-negative bacteraemia. Risk factors for UTI in infants and children are anatomical and functional anomalies (e.g. ureteric reflux, strictures, neurogenic bladder). Women have a shorter urethra than men and so are more prone to bladder infection, particularly after intercourse. Any obstruction to urine flow can predispose to infection. In pregnancy, the ureter is dilated and can be obstructed by the gravid uterus. In elderly men, prostate enlargement obstructs the urethra and in elderly women a cystocele can lead to residual urine volumes in the bladder. Catheterization introduces exogenous flora, which in hospital are often multiresistant. Figure 3.24.2 shows the likely infecting species in the hospital setting and in the community.
