UTIs Flashcards
what is a UTI?
the presence and multiplication of microorganisms in the urinary tract
give examples of clinical syndromes caused by UTIs
cystitis prostatitis Epididymitis/orchitis Urethritis Pyelonephritis
what a re the classifications of UTIs?
Asymptomatic bacteriuria
Uncomplicated
Complicated
what is the difference between bacteriuria and pyuria?
bacteriuria is the presence of bacteria in the urine and pyuria is the presence of leucocytes in the urine
what is sterile pyuria?
presence of white cells in the urine but a pathogen cannot be cultured
what is the most common age group to get asymptomatic bacteriuria?
over 65s
what percentage of people with a catheter will have asymptomatic bacteriuria?
100%
describe the prevalence of asymptomatic bacteriuria
increases with age in both genders
higher in women at all ages
rapid and marked increase with pregnancy
what is the popln that comes under uncomplicated bacteriuria
non pregnant women
what is the popln that comes under complicated bacteriuria
Pregnant Men Catheterised Children Recurrent/persistent infection Immuncompromised Noscomial infection Structural abnormality Urosepsis Associated urinary tract disease
in children who are girls or boys more likely to get UTIs?
girls
if it happens in boys, it is a sign of structural abnormality which needs to be reviewed
what percentage of women experience a UTI in their life?
10-20%
what is the complication of asymptomatic bacteriuria in renal transplant pts?
pyelonephritis
what are some of the causative organisms for UTI?
E. coli - most common causative organism Proteus Klebsiella Enterococci Staph. saprophyticus S. aureus Pseudomonas aeruginosa
which of the bacterial causes is associated with renal stones?
proteus - as it produces ureas which causes an increase in the pH of the urine and this is the pH that stones form at
where does Klebsiella come from?
the gut - it is an Enterobacteriaceae
who does Staph saprophyticus most commonly affect?
young women
what needs to be checked for when we have a pt with Staph aureus bacteriuria?
endocarditis, abscesses, prosthetic joint infections, likes to seed places, can be in the kidneys - so the pt needs to be investigated for a deep infections
What are the G+ cocci that cause UTIs?
Enterococcus
Staph. saprophyticus
Staph aureus
What are the G- bacteria that can cause UTIs?
Neisseria
Enterobacteriaciae ie E.coli and Kelbsiella, Proteus
Bacteroides
what are the culture negative causes of UTI?
mycobacteria Chlamydia Fungi eg Candida albicans Mycoplasma Ureaplasma urealyticum
explain the pathogenesis of UTIs
colonic flora colonises the vagina, then the urethral meatus and then the bacteria ascend further till they cause a UTI
What factors predispose to UTI?
obstruction from prostatic hypertrophy bladder stones or tumour low urinary volume ureteric stones stasis during pregnancy ureteric reflux female short urethra catheterisation low urinary volume eg due to dehydration
what factors make uropathogenic E.coli virulent?
adherence molecules ie fimbriae
toxins that cause extensive tissue damage
What happens post-menopause for the risk of UTI to increase?
after menopause, the pH rises and there is increased colonisation by colonic flora
reduction in vaginal mucus secretion means there is increased vaginal mucosal receptivity to uropathogenic E. coli
How is the normal acidic vaginal pH maintianed?
the normal vagina is heavily colonised with lactobacilli, which metabolise glycogen to lactate which is acidic
What are the symptoms of a UTI?
frequency
dysuria
fever
haematuria
What are the investigations that are done to diagnose a UTI?
collect a urine sample
urinalysis
microscopy
culture and sensitivity
What may be found on urinalysis in a UTI?
blood protein pH change glucose and ketones as diabetics are more prone to UTIs leukocytes nitrates
What are the different types of urine sample?
MSU CSU - catheter specimen of urine early morning urine - for TB SPA - suprapubic aspirate clean catch - clean down below before giving the sample
What may be seen on microscopy with a UTI?
WBCs RBCs casts bacteria epithelial cells