6: Urological Infections Flashcards
what are 5 factors that normally keep the urinary tract sterile and resistant to bacterial colonisation
- emptying of bladder during micturition
- vesico-ureteral valves
- immunological factors
- mucosal barriers
- urine acidity
what does ascending colonisation of bacteria from the urethra lead to in the bladder
cystis
what does ascending colonisation of bacteria from the urethra lead to in the kidney
pyelonephritis
give 6 risk factors for developing a urinary tract infection and explain
- female - short urethra and closer to rectum
- obstructions - stones, enlarged prostate, retroperitoneal fibrosis
- neurological conditions affecting bladder empyting - MS, stroke
- pregnancy - enlarged uterus, hormonal effects on relaxation of musculature
- abnormal renal tract - vesico-ureteric reflex in children, indwelling urinary catheter
- impaired host defence - DM, immunosuppression
at which ages is prevelance of UTIs most common for women and why
- infancy - Genetic abnormalities in urinary tract diagnosed early on
- pre school (5-10) - children first taking responsbility for their own toilet trips (not hygenic)
- 20-30 ‘Honeymoon Cystitis’ - due to increase in sexual activity
- 25-28 - Pyelitis of pregnancy
why does prevelance of UTIs drastically increase for men over age 60
due to BPH - enlarged prostate causing obstruction of urine
what is the most common causative organism of UTIs
coliforms (gram negative organisms) e.g. E.coli
what are virulence factors of E.coli which cause UTIs
- flagellar: movement
- pili: attachment
- capsular polysaccharide: colonisation
- haemolysin, toxins: damages host membranes and causes renal damage
what are less common causative organisms of UTIs
- proteus
- enterococci
- coag negative staph
- staph aureus
what is the difference between cystitis and pyelonephritis
cystitis: lower UTI
pyelonephritis: upper UTI
what are signs and symptoms of cystitis
- dysuria (may be due to other causes of inflammation)
- cloudy urine
- nocturia or frequency
- uregency
- suprapubic tenderness
- haematuria
- pyrexia (usually mild)
what are signs and symptoms of pyelonephritis
- high fever +/- rigors
- loin pain and tenderness
- nausea/vomiting
- +/- symptoms of cystitis
what are some other causes of inflammation that may lead to dysuria
- STIs
- post sexual intercourse
- contact w irritants
- symptoms of menopause, atrophic vaginitis or vaginal atrophy
define an uncomplicated UTI
infection by a usual organism in a patient with a normal urinary tract and normal urinary function
- may occur in males and females of any age
what is a complicated UTI
> 1 factors that predispose to persistent infection, recurrent infection or treatment failure for previous uncomplicated UTI
- abnormal urinary tract
- virulent organism
- impaired host defense (immunosuppression)
- impaired renal function
- suspected pyelonephritis
when are urine cultures not required
in healthy, non-pregnant women of child bearing age (uncomplicated UTI) no need for urine culture
how are complicated UTIs investigated
- Mid-stream urine – cleansing not required, ideally holding labia apart in women
- Clean catch in children
- Culture urine within 4 hours of collection, refrigerate or use boric acid preservative
- urine dipstick to aid diagnosis as visual changes such as cloudy urine will be present
what type of patients are urine dipsticks not useful in
- patients >65 (asymptomatic infection common)
- catheterised patients
what criteria makes urine dipsticks useful
if patient presenting with just 1 of the following:
- dysuria
- new nocturia
- cloudy urine present
if a urine dipstick is negative for nitrites and positive for LE what does it suggest the causative organism is
Staphylococcus saprophyticus
when should imaging of the urinary tract be considered
- all children with UTI
- valuable in septic patients to identify renal involvement (i.e. pyelonephritis)
how should a UTI be treated
- increase fluid intake
- regular analgesia
- address underlying disorders
- antibioticsL 3 day for uncomplicated, 7 day for complicated lower UTI e.g. pregnant, male, underlying disorders
what is the choice of antibiotics for women with cystitis
-
nitrofurantoin - 100mg bd for 3 days
- not effective in renal failure
- cannot be used in final trimester -
trimethoprim - 200mg bd for 3 days
- cannot be used in 1st trimester of pregnancy
what is the choice of antibiotics for men with cystitis
- trimethoprim - 200mg bd for 7 days
- nitrofurantoin - 100mg bd for 7 days
how is pyelonephritis/septicemia treated
- Pyelonephritis 7-14 day course
- Use agent with systemic activity (NOT nitrofurantoin)
- Possibly IV initially unless good oral absorption and patient well enough/tolerating orally
- Cefalexin
- Co-amoxiclav/Trimethoprim (only if culture results available and susceptible)
- Ciprofloxacin (effective as a 7 day course)-Gentamicin
what measures will help to prevent UTIs
- encourage hydration
- promote good hygiene practises
- encourage post-coital voiding
- avoid unnecessary catheterisation
how long do you have to culture urine after taking a sample
within 4 hours of collection
refrigerate or use boric acid preservative if not
what is bacteruria
defined on an MSU as >10^5 colony forming units/ml
- absence of bacterial growth or white cells on an MSU makes UTI v unlikely
do you treat asymptomatic bacteruria or not and why
NO
- actively harmful as it replaces low virulence organisms with something worse
what are the 2 exceptions to treating asymptomatic bacteruria
- pregnancy women (inc risk of preterm labour)
- prior to urological surgery
what other abx options are there for treating UTIs
- cefalexin, augmentin, ciprofloxacin
- IV: augmentin, taozcin, gentamicin, meropenem
how are multi-resistant organisms (MGNO) treated
- in community, some can be treated w trim or nitro if sensitive +/- oral fosfomycin
- IV meropenem
how are recurrent UTIs in women managed
- excluse structural causes w USS +/- cystoscopy
- advise fluid intake, avoid synthetic pants, expensive/perfumed soaps
what are non-abx treatments for recurrent UTIs
- topical oestrogens if post-menopausal
- cranberry tablets
- D-Mannose
- methenamine hippurate
how are abx prescribed for recurrent UTIs
- post-coital - single dose of abx
- self start at first sign of symptoms
- low dose finite 3-6 month prophylactic abx course
what is intravesical treatement for recurrent UTIs
- GAG layer replacement instillations
- intravesical gentamicin
what is the typical history of epididymo-orchitis
acute infection of testis/epididymis
- younger men: STI e.g. chlamydia, gonorrhoea
- older men: coliforms
- gradual onset
- unilateral
- recent H/O viral infection e.g. mumps or drug induced e.g. amiodarone
how would a patient w testicular torsion present
- under 40s
- SUDDEN onset - wake from sleep (>24 hours unlikely to be torsion)
- unilateral pain
- high lying, laterally orientated testis
- Prehn’s/cremasteric reflex
how is testicular torsion managed
emergency scrotal exploration
- reduction and orchidopexy of torted testis if viable
- if non-viable then orchidectomy
- orchidopexy of contralateral testis
how is orchitis managed
- send urine for MSU and NAAT
- USS to exclude abscess or tumour
- PO doxy +/- IM ceftriaxone in younger men & PO ciprofloxacin in older men
- IV abx if septic or unwell
- 10-14 day course
- swelling can take 6-8 weeks to settle
What is positive Prehn’s sign?
Pain is relieved when elevating testicle (eg. In epididymo-orchitis)
- this result is negative in testicular torsion ie. pain is not relieved from elevating testicle
what are the causes of ATN
ischaemia:
- shock
- sepsis
nephrotoxins:
- aminoglycosides
- myoglobin secondary to rhabdo
- radiocontrast agents
- lead
what are the investigation findings of ATN (expected lab results)
- raised urea, Cr, K
- muddy brown casts in urine
- can also present as dark amber, cloudy urine with granular epithelial cell casts
what is decompression haematuria
- occurs commonly after catheterisation for chronic urinary retention due to the rapid decrease in the pressure in the bladder
- usually does not require further treatment and resolves spontaneously over a few days
what is the purpose of cyproterone acetate
- prevents paradoxical increase in symptoms with GnRH agonists
- GnRH agonists may cause ‘tumour flare’ when started, resulting in bone pain, bladder obstruction and other symptoms
