urinary tract infections Flashcards
1
Q
describe the epidemiology of a UTI? 2
A
- 1-3% of all GP consultations
- Significant cause of morbidity in females of all ages, infant boys and older men
2
Q
what are the consequences of a UTI? 6
A
- Societal and individual costs- health care costs, time missed from work
- Frequent recurrences
- Uncontrolled infection- sepsis
- Renal damage in young children
- Preterm birth
- Recurrent causes of AB contribute to antimicrobial resistance and risk of C. difficile infection
3
Q
describe the classifications of UTI? 5
A
- Uncomplicated lower UTI:
- Cystitis
- Urethritis, prostatitis, epididymo-orchitis
- .
- Uncomplicated upper UTI:
- Acute pyelonephritis
4
Q
what is an uncomplicated UTI?
A
there is no anatomical or neurological abnormalities of the urinary tract
5
Q
what is UPEC?
A
uropathogenic Escherichia coli
6
Q
describe the host factors of a lower UTI? 7
A
- Obstruction (prostatic hypertrophy, urethral valves or stricture)
- Poor bladder emptying (neuropathic (MS, spinal cord injury), bladder diverticula, pelvic floor disorders)
- Catheterisation/ instrumentation
- Vasico-enteric fistula
- Sex (vaginal or anal)
- Diabetes
- Genetics= non secretors of ABH blood group antigens, especially in premenopausal women, and variable expression of the CXCR1 receptor, involved in neutrophil action
7
Q
describe the host factors of an upper UTI? 3
A
- Same as lower
- Vesico- ureteric reflux
- Obstruction (calculus, stricture)
8
Q
describe the pathogenesis of a UTI? 10
A
- Contamination of the periurethral area with a uropathogen from the gut
- Colonisation of the urethra and migration to the bladder
- Colonisation and invasion of the bladder, mediated by pili and adhesins
- Neutrophil infiltration
- Bacterial multiplication and immune system subversion
- Biofilm formation
- Epithelial damage by bacterial toxins
- Colonisation of the kidneys
- Host tissue damage by bacterial toxins
- Bacteraemia
9
Q
what does bacterial virulence depend on? 3
A
- Adherence
- Invasion
- Evasion
10
Q
describe adherence in a UTI? 3
A
- In the bladder, uropathogenic Escherichia coli (UPEC) expression of type 1 pili is essential for the colonisation, invasion and persistence
- P-pili confer tropism to the kidney
- UPEC are highly adhesive so are proficient in retrograde ureteral ascent
11
Q
describe the clinical diagnosis of a UTI? 4
A
- Clinical symptoms
- Urine dipstick testing at point of care- main use to determine treatment if symptoms are vague- not diagnostic on their own, not useful if >65 of catheterised
- Urine culture- don’t need to do this in simple 1st episode cystitis in a non-pregnant adult female
- Look for nitrates, leucocytes and RBC
12
Q
what is cystitis? 5
A
ladder and urethral symptoms
- Overlap with urethritis
- Dysuria, frequency, urgency, suprapubic pain, nocturia
- Cloudy urine, visible blood
- Children, elderly and catheterised can be non-specific, such as delirium, lethargy
13
Q
what is pyelonephritis? 5
A
- Fever, rigors, loin pain
- Renal angle tenderness
- Often lower UTI symptoms in addition
- If pain radiation to the groin- stone?
- Risk of bacteraemia
14
Q
describe the laboratory diagnosis of a UTI? 5
A
- Send to lab for culture if- pregnant, children, men, elderly, recurrence, failed treatment, renal impairment
- Principles of a urine culture- urine in the bladder should be sterile in the absence of a UTI
- It can be contaminated by bacteria colonising the distal urethra of hands/genital contamination
- A mid-stream urine (MSU) reduces the effects of urethral contamination by avoiding the initial and end stages of micturition. The initial urine flow washes away urethral colonisers
- Minimise the growth of any contaminants by rapid transport to the land (>4h) and/or boric acid preservative and/or refrigerate
15
Q
describe urine specimens? 3
A
- Midstream urine
- Suprapubic aspirate
- Catheter urine (acute, intermittent self-catheterisation, indwelling)
