MI: Urinary Tract Infection Flashcards
In which situation is asymptomatic bacteriuria clinically significant?
Pregnancy - associated with increased risk of complications
What is the difference between uncomplicated and complicated UTI?
- Uncomplicated - infection in a structurally and neurologically normal urinary tract
- Complicated - infection in a urinary tract with functional or structural abnormalities (includes indwelling catheters and calculi)
In which groups of patients are UTIs considered ‘complicated’?
- Men
- Pregnant women
- Children
- Hospitalised patients
Which organism most commonly causes UTI?
E. coli
List some other organisms that cause UTI.
- Proteus mirabilis
- Klebsiella aerogenes
- Enterococcus faecalis
- Staphylococcus saprophyticus
- Staphylococcus epidermidis (can cause infection in the presence of prosthesis (e.g. procedures, indwelling catheters))
Which virulence factor allows S. saprophyticus to stick to the urinary tract epithelium?
P-fimbriae
NOTE: S. saprophyticus causes infection in young women
List some antibacterial host defences in the urinary tract.
- Urine (osmolality, pH, organic acids)
- Urine flow and micturition
- Urinary tract mucosa (bactericidal activity, cytokines)
What is an ascending UTI?
The infection ascends from the female introitus and periurethral area
List some causes of urinary tract obstruction.
Extra-renal
- Valves, stenosis or bands
- Calculi
- BPH
Intra-renal
- Nephrocalcinosis
- Nephropathy (uric acid, analgesic, hypokalaemic)
- Polycystic kidney disease
Neurogenic malfunction
- Poliomyelitis
- Tabes dorsalis (demyelinating condition caused by advanced syphilis)
- Diabetic neuropathy
- Spinal cord injuries
What is vesicoureteric reflux?
- A condition in which urine can reflux into the ureters
- It results in a residual pool of infected urine in the bladder after voiding
- It can result in scarring of the kidneys
Describe how UTI can become established via the haematogenous route.
The kidney is a frequent site for abscesses in patients with S. aureus bacteraemia or endocarditis (not really a UTI)
NOTE: Gram negative bacilli like E. coli rarely spreads via the haematogenous route
Outline the symptoms of UTI in:
- Neonates and childrne < 2 years
- Children > 2 years
Neonates and children < 2 years:
- Failure to thrive
- Vomiting
- Fever
Children > 2 years:
- Frequency
- Dysuria
- Abdominal pain
List some symptoms of upper UTI.
- Fever (and rigors)
- Flank pain
- Lower urinary tract symptoms
Describe the symptoms of UTI in older patients.
- Mostly asymptomatic
- Atypical symptoms (e.g. confusion)
NOTE: classic symptoms such as frequency and dysuria are common in older people and does not necessarily suggest that there is an infection
List some investigations for uncomplicated UTI.
- Urine dipstick
- MSU for urine MC&S
- Bloods - FBC, CRP, U&E