Week 7 - UTI Flashcards
What can cause obstruction of the urethra and lead to UTIs?
- Prostate enlargement
- Pregnancy
- Tumour
- Stones
What neurological problems increase the risk of UTIs?
-Incomplete emptying/ residual urine
List some virulence factors of UTI pathogens which aid infection
- Fimbrae/pili for attachment
- Haemolysins to damage host membranes and cause renal damage
- K antigen for production of polysaccharide capsule
- Urease to break down urea and create a favourable environment
What is the most likely causative organisms of UTIs in the community?
-Coliforms
What is the most likely causative organisms of UTIs in hospital?
-Staph aureus
What are possible causative organisms of UTIs?
- Coliforms
- Proteus spp.
- Enterococci
- Staphylococci
Give examples of clinical conditions caused by UTIs
- Lower UTI (cystitis)
- Acute pyelonephritis
- Chronic nephritis
- Septicaemia
Describe the symptoms of lower UTI
- Dysuria
- Frequency
- Urgency
Describe the symptoms of upper UTI
- Loin to groin pain
- Fever
- May have dysuria and frequency
When is a UTI classified as uncomplicated?
-In a healthy women with no risk factors
When is a UTI classified as complicated?
-Pregnancy, treatment failure, suspected pyelonephritis, males, paediactric
When does a urine culture need to be done in UTI?
-In a complicated UTI
How is an uncomplicted UTI diagnosed?
-Turbidity and Urine dipstick positive for nitrites and leukocyte esterase
What turns urine cloudy in UTI?
-Presence of WBCs
Explain the specificity and sensitivity of nitrites on a dipstick
- Poorly sensitive as can only detect a limited number of bacteria so a ned result does not rule out infection
- Highly specific as if it is positive it is most likely UTI
Explain the specificity and sensitivity of leucocyte esterase on a dipstick
-High sensitivity with good specificity
When is microscopy indicated in UTIs?
- Kidney disease -> nephritis, renal colic,
- Suspected endocarditis
- Children under 6
- Schistosomiasis
What is the purpose of urine culture?
- Investigation of complicated UTI
- Epidemiology of isolates
- Abx susceptibility
What are some differential diagnoses to UTI?
- STI
- mechanical/physical causes
- vaginal infection (thrush)
- Renal TB
Why may someones urine be sterile upon presenting with infection?
- Already on Abx
- STI
- Thrush
- TB
Outline the treatment of a UTI
- Increase fluid intake
- Address underlying disorders
- 3 day course trimethoprim for uncomplicated and 7 days for complicated
What are the two main drugs for UTI treatment?
- Trimethoprim
- Nitrofurantoin
Why is amoxicillin not appropriate for UTIs?
-50% strains are resistant
How do you treat pyelonephritis?
- 14 day course
- ciprofloxin or IV gentamycin
When is prophylaxis considered for UTIs?
-When more than 3 or more episodes in one year and there is no treatable underlying condition
NAme the defences of the urinary tract to bacteria
- Regular flushing
- Antibacterial secretion into urine and urethra
What is sterile pyuria?
-White blood cells in urine without bacterial growth
Why is there more incidence of UTIs in females?
-Shorter urethra
When is it necessary to do 3 urinary specimens?
-When TB is suspected
When should UTIs have a follow up?
-Children and pregnancy
When is Abx treatment indicated in a catheter sample?
-When pt is systemically unwell
