S9) Urinary Tract Infections Flashcards
Identify and describe 4 causes of UTI’s (host factors)
- Shorter urethra – more infections in females
- Obstruction – enlarged prostate, pregnancy, stones, tumours
- Neurological problems – incomplete emptying, residual urine
- Ureteric reflux – ascending infection from bladder
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)
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
- Frequency
- Urgency
- Low grade fever (sometimes)
Identify 4 signs and symptoms of upper urinary tract infections (pyelonephritis)
- Fever
- Loin pain
- Dysuria (sometimes)
- Frequency (sometimes)
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)
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 sample)
- Catheter sample
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)
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)
