So the urinary tract does have some defense
against the urinary tract pathogens.
It's got these glycosaminoglycans or gag layer
that's in the normal mucus of the urinary tract.
This is a sulfonated surface polysaccharide
that covers the umbrella cells and the surface mucosal cells
that are polypoid or octaploid with their tight junctions.
So you got this lining that covers that,
and this glycosaminoglycan prevents the passage of urine
into or through superficial cells
One point I'd like to make about it
is that there are patients who have a condition called interstitial cystitis
where this glycosaminoglycan is not intact.
And since urine is normally acid,
you can get acid urine into the deep layers of the bladder,
and these poor patients have a chronic problem with cystitis
but it's not of infectious nature.
Now, back to cystitis
the shorter urethra in women is obviously closer to the anus
and closer to colonic flora
and so the organisms that are going to cause urinary tract infection
are in the vaginal introitus and the periurethral area.
And when the urethra is massaged in women
especially by sexual intercourse
those bacteria can be forced into the bladder.
Furthermore, if the bacteria are motile
they can actually ascend the urinary tract
against the urine stream.
Most notorious among these bugs would be Proteus, which has swarming motility in many species.
Now how does it present -- cystitis in children?
It's pretty non-specific. You can't tell that the child is having problems
unless they're, for example, having enuresis.
A child wasn't bed wetting and now starts bed wetting.
Fever may be a clue.
Failure-to-thrive in infants,
and if they start vomiting
a good pediatrician or a family physician is going to be thinking of an infection.
Now in women, almost all of them, have frequent painful urination
of small amounts of turbid urine.
They may have also kind of some suprapubic pain or heaviness
and they usually do not have fever.
Now in men,
they have some of the same symptoms, but if they've got fever
it may be a focus in the prostate gland
or worse, it could be a kidney infection -- pyelonephritis.