UTIs Flashcards
what is an infection?
it is an invasion of the body tissues by a pathogenic organism that causes an immune response which gives rise to symptoms
what is a UTI?
an infection of any part of the urine tract
what causes UTIs most commonly?
an endogenous bacteria that has got into the wrong place and invaded
where is the prostate gland?
it lies below the bladder
what areas are sterile in the UT?
the kidneys, ureter and the bladder
why is the urethra not sterile?
perineal flora is found in it
what are some predisposing factors for UTIs?
urinary stasis, urological instrumentation, female, sexual intercourse, fistulae and congenital abnormalities
what is the epidemiology of UTIs?
mostly in sexually active women
M:F is 10:1
what fistulae can there be ?
recto-vesical and vesico-vaginal
what congenital abnormalities are there that affect UTI predisposition?
VUR - vesico-ureteric reflux
what are causes of urinary stasis?
pregnancy, prostatic hypertrophy, stones, strictures, neoplasia and poor bladder emptying leading to residual urine
what are the main flora on the skin?
the coagulase negative staphylococci
what are the lower GIT flora?
there is internal colonising bacteria that are often found on the skin around the relevant orifice
there is anaerobic and aerobic bacteria
aerobic can be enterbacterales - these are coliforms and enteric gram negatic bacci
they are also gram positive cocci such as the enterococcus species
what are the two main sources of bacteria?
endogenous and haematogenous which is rare
what is meant by endogenous spread?
most infections are cause by gut bacteria - this is the enteric flora such as the perineal flora, and there is movement of bacteria along a lumen such as in fistulae
also movement from the GIT or genital tract
what is haematogenous spread?
spreading of the bacteria to the urinary tract via the blood such as with staphylococcus aureus
what is the most common UTI bacteria?
E coli
others include staph saprophyticus (GP)
enterococcus (hospitals)
pseudomonas
other than causing UTIs what else can these bacteria do?
contaminate poorly taken samples, colonise catheters such as from nephrostomy and urostomy, and cause asymptomatic bacteriuria - particularly in over 65s
what are the key to diagnosis and what does microbiology do?
clinical signs and symptoms are the key
they guide the identification and appropriate directed treatment
what is asymptomatic bacteriuria?
no symptoms of a UTI but culture urine sample grows a single organism in significant numbers
what are the symptoms of UTIs?
rigors, fevers, haematuria, dysuria, back and loin pain and suprapubic pain
urgency, systemic infection, pus, polyuria and nocturia
what is cystitis?
it is a lower UTI that is more common in women - dysuria, frequency, urgency, haematuria, nocturia, polyuria, suprapubic pain or tenderness
what is pyelonephritis?
it is an infection of the kidney or the renal pelvis
it gives symptoms of the lower UT with loin or abdo pain or tenderness, fever and other systemic symptoms such as nausea, vomiting, diarrhoea, rigors, elevated CRP and WBC
what is a complicated UTI?
there is an underlying abnormality such as structural or functional, urinary stasis due to obstruction or retention, presence of a foreign body, catheter, renal calculi or biofilm
what is an uncomplicated UTI?
absence of the signs of complicated that occurs in children under the age of ten or men under 65
what is a catheter associated UTI?
indwelling catheterisation can result in bacteriaemia and removal or manipulation can result in this
what can be used if there is potential for CA uti?
antibiotic prophylaxis
what are the implications for antibiotic prophylaxis?
previous symptomatic CA UTI, traumatic insertion, purulent urethral or suprapubic catheter exit site discharge or colonisation with staph aureus or MRSA
what cannot be used in CA UTI?
dipsticks are no use - there is no distinguisment between sterile and normal sites
what are procedure that result in CA UTI?
nephrostomy - haematuria or purulent discharge, pain or tenderness at site and fever
ileal conduit or urostomy - fever, ascending infection
parastomal skin infections - redness, swelling and pus
what is a nephrostomy?
it is a percutaneous line straight to the kidney
what is an ileal conduit/urostomy?
short section of ileum used to drain the ureters directly to a stoma on the anterior abdo wall after cystetomy
why are symptoms key?
like catheteres there is colonisation of the bag and the tubing
what is urosepsis?
systemic signs of infection related to any underlying urinary source of infection - fever, rigors, nausea, vomiting, diarrhoea
may be haemodynamic compromise and raised inflammatory markers such as CRP or WBC
why is it important to differentiate urosepsis from pyelonephritis?
often thought to be akin to pyelo but there are no clinical signs