S9) Urinary Tract Infections Flashcards
Identify and describe causes of UTI’s (host factors)
- Shorter urethra – more infections in females
- Obstruction – enlarged prostate (men later on BPH), pregnancy, stones, tumours
- Neurological problems – incomplete emptying, residual urine, MS, stroke pathways don’t sync up
- Ureteric reflux – ascending infection from bladder
- pregnancy - enlarged uterus, hormonal effects on uterus
- impaired host defence - diabetes, immunosuppressed
Identify the different sites (A-C) of urinary tract obstruction and point out their respective causes
A – PUJ: calculi
B – Ureter: calculi, Ca2+, retroperitoneal fibrosis
C – Bladder: neuropathic bladder
Identify the different sites (D-G) of urinary tract obstruction and point out their respective causes
D – VUJ: calculi
E – Bladder neck: hypertrophy
F – Prostate: BPH / Ca2+
G – Urethra: stricture
Describe 4 causes of UTIs (bacterial factors)
- Haemolysins damage host membranes and cause renal damage
- Fimbriae allow attachment to host epithelium
- K antigen permits production of polysaccharide capsule
- Urease breaks down urea encouraging bacterial growth
What is the primary causative organism for UTI’s?
Coliforms (E. coli, etc)
flagella - move
pili - to attach
capsular polysaccharide - colonisation
haemolysin toxins - damage host membrane and causes renal damage
Identify 5 clinical conditions where UTIs are commonly observed
- Cystitis (lower UTI)
- Acute pyelonephritis (upper UTI)
- Chronic pyelonephritis
- Asymptomatic bacteriuria e.g. pregnancy
- Septiceamia (± shock)
Identify 4 signs and symptoms of lower urinary tract infections (cystitis)
- Dysuria - pain peeing
- Frequency
- Urgency
- Low grade fever (sometimes)
- cloudy urine
- haematuria
- nocturia
Identify 4 signs and symptoms of upper urinary tract infections (pyelonephritis)
- Fever
- Loin pain
- Dysuria (sometimes)
- Frequency (sometimes)
- nausea and vomiting
What is an uncomplicated UTI?
An uncomplicated UTI is an infection caused by a usual organism in a patient with a normal urinary tract and normal urinary function (occur in males & females of any age normally non pregnant )
What is a complicated UTI?
A complicated UTI is an infection occurring when 1/more factors are present that predispose the person to persistent infection, recurrent infection, or treatment failure
Provide 4 examples of situations when a complicated UTI occurs
- Abnormal urinary tract e.g. vesicoureteric reflux, indwelling catheter
- Virulent organism e.g. Staph. aureus
- Impaired host defences e.g. poorly controlled diabetes, immunosuppression
- Impaired renal function
When would one investigate a UTI with a urine culture (microscopy)?
Complicated UTI – pregnancy, recurrent infections, suspected pyelonephritis, male, children
Identify 3 ways in which the urine specimen can be collected when treating a UTI
- Supra-pubic aspiration
- MSU (midstream urine culture and sample)
- Catheter sample
- urine dipstick
What does one test for in urine dipstick testing?
- Leucocyte esterase
- Nitrite
- Haematuria
- Proteinuria
What does one look out for in a visual inspection of a urine sample?
Turbidity
Compare and contrast the sensitivity, specificity and NPV urine dipstick testing and visual inspection
When is dipstick testing useful?
Excludes UTI in:
- Children >3yrs
- Men with mild/non-specific symptoms
- Elderly/institutionalised women
When is dipstick testing not useful?
- Acute uncomplicated UTI in women
- Men with typical/severe symptoms
- Catheterised patients
- Asymptomatic bacteriuria (older patients)
Outline a differential diagnosis for a symptomatic adult women
- 50% significant bacteriuria
- 50% urethral syndrome – vaginal infection/inflammation, STI, mechanical, physical & chemical causes
Imaging of the urinary tract is valuable in septic patients to identify renal involvement.
What is visualised for males and females respectively?
- Males: posterior urethral valves
- Females: vesico – ureteric reflux
What causes sterile pyuria?
- Antibiotics
- Urethritis (chlamydia/gonococci)
- Vaginal infection/inflammation
- Tuberculosis
- Appendicitis
Outline the general treatment of UTI’s (4 components)
- Increase fluid intake
- Treat underlying disorders
- Antibiotics
- Chronic spontaneous urticaria (only treat if systemically unwell)
Outline the treatment of simple cystitis
Uncomplicated infections can be treated with trimethoprim or nitrofurantoin (3 day course)
3 days to reduce resistance
Outline the treatment of a complicated lower UTI
- Trimethoprim, nitrofurantoin or cephalexin (5-7 day course)
- Post treatment follow-up cultures in paediatric patients and pregnant women
Not amoxicillin – 50% resistance
Outline the treatment of pyelonephritis / septicaemia
- Co-amoxiclav (14 day course)
- Ciprofloxacin (effective as a 7 day course)
- Gentamicin (IV only – nephrotoxic)
When is antibiotic prophylaxis given for UTIs?
- 3/more episodes in one year
- No treatable underlying condition
Which antibiotics are prescribed for UTI prophylaxis?
Trimethoprim or nitrofurantoin (single nightly dose)
where are lower UTIs found
in the bladder and the urethra
cystitis
where are upper UTIs found
in the kidneys (pyelonephritis) and the ureter
when are urine dipsticks useful
- not useful in patients > 65 as its normal that they will be positive for some nitrites and leukocytes so only think its a UTI if they have symptoms for it
- useful for patients presenting with:
- dysuria
- new nocturia
- cloudy urine
- positive for nitrites
which organism will cause a dipstick result for positive of nitrates
staphylococcus saprophyticus
it doesn’t reduce nitrites into nitrates
what is a a secondary condition of UTIs that you should look out for
SEPSIS
multi organ failure
will see a drop In BP to suggest there is CVS failure
if the patient has pyelonephritis then sepsis can occur
when should you not give a patient nitrofurantoin
when they already have some sort of kidney damage, only give if their kidney is healthy
this is also a very specific drug so only give if you know the exact agent don’t give if they have pyelonephritis
