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
what is urethritis?
it is inflammation of the urethra
why does urethritis occur?
some STIs can cause urethral symptoms such as gonorrhoea
thrush - vulvovaginal candidiasis - irritation and symptoms such as dysuria
urethral syndrome
what is urethral syndrome?
it is a controversial term that is symptoms of the lower UT without any demonstrable infection - abacterial cystitis frequency-dysuria syndrome
mostly affects women that are 30-50 years old
where can UT abscesses be?
perinephric or intra renal
what is perinephric abscess?
it is an uncommon complication or renal stones or diabetes and a secondary complication to obstruction of the infection kidney that is caused by gram negative bacilli
what is a intrarenal abscess?
it is from haematogenous spread resulting in unilateral, single renal cortex abscess from staph aureus or can be associated with classic acute pyelonephritis - cortex or medulla
what types of prostatitis are there?
chronic or acute bacteria
what is prostatitis?
inflammation of the prostate
what are the signs and symptoms for acute prostatitis?
fever, tender and tense on examination by PR, acute retention and lower UT symptoms
what are the typical pathogens for acute prostatitis?
the usual UTI ones - S aureus or E coli
what are the risk factors for acute prostatitis?
procedures involving the prostate - trans urethral resection or trans rectal USS guided
indwelling urinary catheters
what are the symptoms of chronic prostatitis?
enlarged or tender prostate on examination, tender or pain around the perineum or genitalia and lower UT symptoms
what is the main cause of chronic prostatitis?
over 90% are due to chronic pelvic pain syndrome - negative urine culture and non bacterial
what is chronic bacterial prostatitis?
it is recurrent UTIs with the same organism that is asymptomatic inbetween
what is the function of imaging in UTIs?
is the urinary tract anatomically normal, identify stones, abscesses and guide therapy
what are the functions of investigations into UTIs?
to confirm clinical suspicion, find the pathogen and best treatment, direct the approach, confirm empirical choice and prompt change, narrowest spectrum of ABs and little damage to microbiome, and monitor response with inflammatory marker trends
What are the types of microbiological investigations?
dipsticks, ward tests and urinalysis
what is the benefit of microbiological tests?
quick screen suitable for between 3 and 65 years as reliable
when can microbiological tests not be used?
in over 65s, for 3months - 3 years if high risk need to send for culture regardless of result, less than 3 months, catheter samples
what do dipsticks test for?
blood, protein, nitrite and WBCs
what samples are used in microbiological lab/ward tests?
MSU, CSU, urine, SPA, clean catch, pad bag (paediatric), blood cultures
what tests are done for suspected pyelonephritis or severe sepsis?
microscopy, culture and sensitivity testing
what do lab tests use?
utilises clinical information such as age gender pregnancy status symptoms antibiotics and allergies
why use MSU?
initial stream gives bacteria that colonises the urethra - midstream will give those in bladder or upper UT
what should sample bottles be?
sterile, not decanted into from non sterile containers, preservative with boric acid, right amount of urine and preventing over growth
what is MSU?
it is antibiotic susceptibility testing and semi quantitative cultures
what does the RCC and WCC indicate?
RCC - bleeding
WCC - inflammation
what does the presence of epithelial cells indicate?
contamination
what is made of the antibiotic results?
tailored to the syndrome, allergies and current treatments considered
what does bacterial growth show?
in the presence of symptoms there is confirmation of diagnosis but is impossible to interpret properly without symptoms
what is sterile pyuria?
it is when there is raised WCC and pus cells in the urine but no organisms grown with standard lab methods
why might organisms not be grown with normal lab methods?
inhibition of bacterial growth due to ABs or specimen contaminated with antiseptic
fastidious / hard growing organisms such as mycobacterium TB or anaerobes
urinary tract inflammation due to renal or bladder stones or disease
urethritis due to sexually transmitted pathogens such as chlamydia or gonorrhoea
what are special lab tests?
early morning urine x3
if suspected urinary TB
need to request a acid fast bacilli specifically - usually by specialists
what is done if there is poor sensitivity in the tests?
a tissue biopsy at the site of suspected disease
what are indications for further investigations in UTIs?
in childhood, males, recurrent or pyelonephritis
what are the investigations done for UTI if needed to go further?
renal tract USS CT KUB specialised tests isotope scans such as a MAG3, DMSA or DTPA micturating cytourethrogram
what is the non antimicrobial management of UTIs?
fluid intake, anti inflammatories, device removal if no longer indicated, or changed if needed, drainage if obstruction or abscess, cranberry juice or extract
what is recurrent UTIs?
reinfection or bacterial persistence - significant will be over three episodes in 12 months
what are the ideal UTI ABs?
gets into the urine, little resistance, little collateral damage, minimally toxic, effective against the likely organisms, easily administered and cheap
what are examples of UTI ABs?
nitrofurantoin, pivmecillinam, trimethoprim and fosfomycin
what is nitrofurantoin used for?
lower UTIs only
inadequate for systemic infections
not for prostatitis
how is cystitis treated in females?
treatment will often preempt microbiology results, short course of antibiotics for 3 days and in mild cases then a delayed prescription if the increased fluids and ibruprofen do not work
what needs to be considered if there are recurrent UTIs in men?
prostate
what is done in recurrent UTIs or males?
longer course of ABs for 7 days
what is the treatment of pyelonephritis?
it is empirical or directed
empirical:
systemically active, broad action against likelym, e.g. cefuroxime, aztreonam, ciprofloxacin or gentamicin
directed:
sensitivity results - narrowest spectrum, not all agents are suitable for a PO stepdown such as nitrofurantoin
7 days depending on AB used
how is prostatitis treated?
it needs to be active against the likely agent and penetrate the prostate which is poor in most ABs. Penetration is better in the inflammation in acute prostatitis. Empirical options are piperacillin-tazobactam (IV) or ciprofloxacin (IV or PO). Directed is trimethoprim or co-trimoxazole and the duration is 2-4 weeks
who is treated with asymptomatic bacteria?
only those in specific groups
pregnant
association w upper UTI - preterm delivery and low birth weight babies
infants
prevention of pyelonephritis and renal damage
prior to urological procedures
prevention of UTI and bacteriaemia
why do the elderly or catheterised not required antibiotics?
it is common in over 65s
how can you treat recurrent UTIs in adults?
lifestyle modification or antimicrobial strategies
what is incorporated in lifestyle modification?
increased fluid intake. review of contraception, voiding before and after coitus, oestrogen replacement in post menopausal women, cranberry products
what is incorporated in review of contraception?
away from spermicide and cervical diaphragm
what is incorporated in antimicrobial strategies?
acute self treatment - course at home
continuous prophylaxis with methanamine hippurate
no catheter and acidic urine
what are the arguments for and against prophylactic ABs?
resistance and therefore breakthrough infections with resistant organisms with AB use
short term benefit in those who have recurrent infections
