UTI Flashcards
definition of UTI
bacturia - bacteria in the urine - this is not a disease, can be symptomatic or not
UTI - dx based on sx and signs, tests that show bacteria in urine may provide more info
Characterized by presence of>100,000 of colony-forming units per ml of urine.
may affect bladder (cystitis), kidney/renal pelivis (pyelonephritis) or prostate (prostatitis).
lower UTI - cystitis, prostatitis
upper - pyelonephritis
abacterial cystitis/urethral syndrome - dx of exclusion in patients with dysuria and frequency, without demondtratable infection
aetiology of UTI
usually transurethral ascent of normal colonic organisms
most common - E coli
others include Proteus mirabilis, Klebsiella and Enterococci (more common in hospitals).
epidemiology UTI
common in females - 30% experience UTI at some point
seen in 5% pregnant women, 2% non-preg, 20% of elderly living at home and 50% of institutionalised elderly
UTI is rare in children and young men (if present, suspect an underlying cause).
Annual incidence of UTI in women is 10–20%.
10% of men and 20% of women >65 years have asymptomatic bacteriuria (>65 years MSU is no longer diagnostic and clinical assessment is mandatory).
Pyelonephritis = 3 per 1000 patient years
general sx of UTI
may be asymptomatic bacturia
Up to 30% of women with UTI symptoms may not have bacteruria
sx of cystitis
frequency
urgency
dysuria - pain on micturition
haematuria
suprapubic pain
smelly urine
sx of acute pyelonephritis
fever
malaise
rigors
loin/flank pain
vomiting
costovertebral pain
associated cystitis sx
septic shock
sx of prostatitis
fever
malaise
nausea
low back/perineal/rectum/scrotum/penis/bladder pain
irritative/obstructive symptoms - hesitancy, urgency, intermittency, poor stream, dribbling
swollen or tender prostate on PR
sx of UTI in elderly
malaise,
nocturia,
incontinence,
confusion
signs of cystitis
asymptomatic
fever
abdo/suprapubic/loin tenderness
bladder distension
signs of pyelonephritis
asymptomatic
fever
loin/flank tenderness
signs of prostatitis
asymptomatic
tender
swollen prostate
ix for uti
In non-pregnant women, if ≥ 3 (or one severe) symptoms of cystitis, and no vaginal discharge, treat empirically without further test
midstream urine
- dipstick test
- use in non-pregnant women <65 years with less than three symptoms. A negative dipstick reduces probability of UTI to <20%. Do not use in pregnant women. Limited data for men.
- nitrites (urinary bacteria reduces nitrites to nitrates)
- leucocytes
- protein
- blood
- microscopy, culture and sensitivity
- >=10(5)colonies/mL indicates a significant bacteriuria, but in the presence of UTI symptoms, the threshold is lower, in women (>10(2)/mL) and in men(>10(5)/mL).
- Use in pregnant women, men, children, and if fail to respond to empirical antibiotics. Catheterized sample only if septic.
- if sterile pyuria (pus cells with no organisms) - consider if may be partially treated UTI, TB stones, tumour, interstitial nephritis or renal papillary necrosis
blood - only if systemically unwell (FBC, UE, CRP, blood culture - positive in only 10–25% of pyelonephritis. consider fasting glucose)
renal US or IV urogram considered in women with frequent UTIs, and in children and men
- exclude predisposing structural/functional abnormalities.
cystoscopy, urodynamics, CT from urology for men with upper UTI, failure to respond to treatment, recurrent UTI (>2/yr), pyelonephritis, unusual organism, persistent haematuria
Mx of cystitis
If three or more symptoms (or one severe) of cystitis, and no vaginal discharge; consider local microbiological policies: co-trimoxazole, trimethoprim, nitrofurantoin (if eGFR >30) or amoxicillin (in non-pregnant females) and ciprofloxacin (males).
If first-line empirical treatment fails, culture urine and treat according to antibiotic sensitivity
If symptoms suggest prostatitis (pain in pelvis, genitals, lower back, buttocks) consider a longer (4-week) course of a fluoroquinolone (eg ciprofloxacin) - ability to penetrate prostatic fluid
Mx for pyelonephritis
IV gentamicin, cefuroxime, ciprofloxacin
women
- take culture and treat initially with broad spectrum AB eg co-amoxiclav
- consider hospitalisation because of AB resistence
- Avoid nitrofurantoin as it does not achieve eff ective concentrations in the blood.
men - refer to urology
Mx for catheterised pts - UTI
obtain culture and consider changing catheter
only treat if symptomatic - catheters invariably get colonised
UTI prophylaxis
high fluid intake
regular micturition to keep bladder empty
cranberry based products reduce frequency of recurrence
In some cases, low-dose long-term (6–12 months) antibiotics for women with frequent UTIs.
surgical Mx for UTI
rarely necessary
relief of obstruction and removal of any renal calculi
complications for UTI
Renal papillary necrosis (in those with underlying renal disease, e.g. diabetes mellitus or stones).
Renal/perinephric abscess (seen on renal ultrasound).
Pyonephrosis (pus in palvicalyceal system)
Gram-negative septicaemia.
prognosis for UTI
Mostly resolve with treatment.
Among pregnant women, 20% developacute pyelonephritis if not treated;
there is a high relapse rate.
uncomplicated UTI
normal renal tract structure and function
complicated UTI
structural/functional abnormaloty of GUT eg obstruction, catheter, stones, neurogenic bladder, renal transplant
RF for UTI
increased bacterial inoculation - sexual activity, urinary incontinence, faecal incontinence, constipation
increased binding of uropathic bacteria - spermicide use, low oestrogen, menopause
reduced urine flow - dehydration, obstructed urinary tract
increased bacterial growth - DM, immunosuppression, obstruction, stones, catheter, renal tract malformation, pregnancy
general signs for UTI
fever
abdo or loin tenderness
check for distended bladder, enlarged prostate
if vaginal discharge consider PID
dont rely on classical sx and signs in a catheterised pt
organisms for UTI
usually anaerobes and gram -ve bacteria from bowel and vaginal flora
E coli is the main organism (75-95% in community byt less in hospital)
Staphylococcus saprophyticus (a skin commensal) in 5–10%.
Other enterobacteriaceae such as Proteus mirabilis and Klebsiella pneumonia.
infection causes of sterile pyuria (high WCC, sterile on standard culture)
TB
recently treated UTI
inadequately treated UTI
fastidious culture requirement
appendicitis, prostatitis, chlamydia
non-infectious causes of sterile pyuria
calculi
renal tract tumour
papillary necrosis
tubulointerstitial nephritis
chemical cystitis
polycystic kidney
recent catheter
pregnancy
SLE
drugs eg steroids
Mx of UTI in pregnancy
expert help
associated with pre-term delivery and intrauterine growth restriction
. Asymptomatic bacteriuria should be confi rmed on a second sample.
Treat with an antibiotic
Mx of UTI in catheterised patients
all are bacteriuric - only send MSU if symptomatic
symptoms of UTI may be non-specific or atypical
fever, flank/suprapubic pain, change in voiding pattern, vomiting, confusion, sepsis
change long term catheter before starting AB
urinary tract TB
A cause of sterile pyuria: dysuria, frequency, suprapubic pain but negative standard culture
malaise, fever, night sweats, weight loss, back/flank pain, visible haematuria
can cause interstitial nephritis and renal amyloidosis. glomerulonephritis is rare
dx by microscopy with acid-fast techniques adn mycobacterial culture of an early morning MSU and or urinary tract tissue
Treat with rifampicin and isoniazid for 6 months in conjunction with pyrazinamide and ethambutol for 2 month
