Theme 4 Lecture 5: Urinary Tract Infections Flashcards
What is a UTI?
- An infection of any part of your urinary system
- an immune response, gibing rise to symptoms. if there are no symptoms, the bacteria are not causing harm
What are the risk factors for UTIs?
- female sex –> 10:1 female: male ratio to short urethra
- anything that leads to urinary stasis - pregnancy, prostatic hypertrophy, stones, strictures, neoplasia
- urological instrumentation e.g catheters
- sexual intercourse
- fistulae
- congenital abnormalities e.g VUR
Which parts of the urinary tract should have bacteria, and which shouldnt?
- kidney, ureter shouldn’t have any bacteria
- urethra, perineum will have bacteria
- bladder is debatable (as you get older it is more common to have asymptomatic bacteria)
- essentially, the further you go up the urinary tract, the less you should have any bacteria
What makes up perineal flora? (found in the urethra)
- skin flora (mainly coagulase negative staphylococci)
- lower GI tract flora
- enterobacterales (coliforms - usually enteric gram -ve bacilli)
- gram +ve cocci - enterococcus spp
Where are the two places invading bacteria in the perineum can come from?
- endogenous
- most infections are caused by gut bacteria - haematogenous spread (rare)
- seeding of bacteria to the urinary tract via the blood
What are the organisms that commonly cause UTIs?
- E.coli
- staphylococcus saprophyticus (CNS)
- proteus mirabilis
- enterococcus spp
- klebsiella spp
- pseudomonas aeruginosa
How do you know if you should treat UTIs?
- clinical signs and SYMPTOMS
- and microbiology results guide you to the culprit and appropriate, directed treatment
What are the symptoms of UTIs? (14)
- urgency
- systemic - fever, pain
- retention
- loin
- rigors
- fevers
- back pain
- frequency
- pus
- polyuria
- dysuria
- supra-pubic pain
- haematuria
- nocturia
What are the symptoms of cystitis (lower UTI)?
- dysuria
- frequency
- urgency
- supra-pubic pain or tenderness
- polyuria, nocturia, haematuria
What is pyelonephritis?
- swollen kidney and ureter also filled with pus
- infection of kidney/renal pelvis
What are the symptoms of pyelonephritis?
- symptoms of lower UTI
- loin/abdominal pain or tenderness
- fever
- other signs of systemic infection: rigors, nausea, vomiting, diarrhoea
- elevated CRP, WBC
what features make a UTI a ‘complicated’ UTI?
- underlying abnormalitity e.g stone
- urinary stasis
- presence of ‘foreign body’
- catheter
- biofilm
- children < 10-12
- men < 65
What is a CA-UTI?
Catheter associated UTIs:
indwelling catheterisation results in bacteriuria - they should be removed the moment they are not needed
biofilm formation (bacteria forming around the catheter) –> colonisation
In what patient groups is antibiotic prophylaxis indicated?
- previous symptomatic CA-UTI with catheter change/removal
- traumatic catheterisation (if t has taken two or more attempts to insert a catheter)
- purulent/ urethral suprapubic catheter exit site discharge
- colonisation with staph aureus inc MRSA
What is a urinary ‘ostomies’
holes we make to get urine out other than catheters
What are the two types of urinary ‘ostomies’?
- nephrostomy - percutanoeus straight into kidney
- ileal conduit/ urostomy - short section of ileum removed and used to drain ureters directly into a stoma on the anterior abdominal wall after cystectomy
What is urosepsis and what are the symptoms?
Systemic signs of infection related to any underlying urinary source of infection:
- urinary
- rigors
- nausea, vomiting, diarrhoea
- +/- haemodynamic compromise
- raised inflammatory markers (CRP, WCC)
what is ‘urethral syndrome’
symptoms of lower UTI without any demonstrable infection
What is a perinephric urinary tract abscess?
- uncommon condition
- renal stones and/or diabetes
- secondary to obstruction of infected kidney
- normally gram -ve bacilli
What is a intrarenal urinary tract abscess?
- haematogenous spread
- staph aureus common
What is prostatitis?
inflammation of the prostate
What are the signs and symptoms of acute bacterial prostatitis?
- LUT symptoms
- fever
- tender, tense prostate on PR palpitation
- acute retention
What are the risk factors for acute bacterial prostatitis?
- procedures involving the prostate
- trans-urethral resection of prostate (TURP)
- trans-rectal ultra-sound guided (TRUS)
- indwelling urinary catheter
What is chronic bacterial prostatitis
recurrent UTIs with the same organism
asymptomatic in between
Which microbiological investigations are used for UTIs?
- dipstick
- ward-tests
- urinalysis
When should you not use microbiological investigations?
- catheter samples (these always have bacteria)
- unreliable in > 65y
- in children: do not use if <3 months, 3m-3y can use, >3yr is reliable
What do dipsticks tell us?
- blood
- protein
- nitrite
- white blood cells (leucocyte esterase)
Why does the urine being investigated need to be mid-stream?
- the initial stream will pick up the bacteria colonising the urethra
- the midstream better represents any bacteria actually in the bladder
What is ‘sterile pyruria’
-pus cells (raised WCC) in the urine but no organisms grown with standard lab methods
What are some causes of sterile pyuria?
- inhibition of bacterial growth e,g antibiotics (collect sample before starting)
- specimen contaminated with antiseptic
- ‘fastidious’ (hard to grow) organisms e.g mycobacterium tuberculosis, anaerobes
- urinary tract inflammation
- urethritis (sexually transmitted pathogens) - neisseria gonorrhoea, chlamydia trachomatis
What do specialists do if they suspect urinary tuberculosis?
- early morning urine sample (EMU) x3
- need to request acid fast bacilli (AFBs) specifically
What are the 4 indications for further investigations of UTIs?
- recurrent UTI
- any UTI in male patient
- any UTI in childhood
- pyelonephritis
What is the non-antimicrobial management methods of UTIs?
- excess fluid intake
- antiinflammatories e.g NSAID, ibruprofen
- device removal if no longer needed
- draining if obstruction/abscess
What are the requirements of a good UTI antibiotic?
- needs to get into urine
- minimally toxic
- effective against likely organisms
- easily administered and cheap
What are 4 examples of UTI antibiotics?
- nitrofurantoin
- pivmecillinam
- trimethoprim (although high resistance)
- fosfomycin
What are the benefits and limitations of using nitrofuratoin?
- inadequate for systemic infections
- lower UTIs only
- not good prostatitis
however:
- has good activity with gram -ve and few gram +ve that cause UTIs
- not huge issue with resistance as only used for bladder infections
What is the treatment of cystitis for females?
short course of antibiotics for 3 days
What is the treatment of cystitis for males?
longer course - 7 days
Which antibiotics can we use to treat pyelonephritis?
- cefuroxime
- axtreonam
- ciprofloxacin
- gentamicin
for 7-14 days depending on the antibiotic
Why is it slightly more difficult to treat prostatitis?
most antibiotics have poor penetration into prostatic tissue
What can we use to treat prostatitis and how long is the treatment duration?
Empirical options
-piperacillin-tazobactam or ciprofloxacin
Directed options:
as above or trimethoprim
duration is 2-4 weeks
In which groups would you treat asymptomatic bacteruria?
- pregnant women - associated with upper UTI, pre-term delivery and low birth weight babies
- infants - prevent pyelonephritis and renal damage
- prior to urological procedures
If a middle age male patient has recurrent UTI symptoms would you treat them?
yes as you must think about the prostate and treat with prostate active agent
