L14 - Sexually Transmitted & Urinary Tract Infections Flashcards
What is the anatomy of the urinary tract?
Kidneys to
Ureters to
Bladder to
Urethra
What are risk factors for UTIs?
Pregnancy
Age
Females
Indwelling catheters
Describe asymptomatic bacteriuria
No adverse outcomes on follow up
More common in the elderly/catheterised
Describe the ascending route of pathogenesis
Bacteria ascend through urinary tract via:
Intestinal Flora - Selection of uropathogenic strains
Vaginal/Peri-urethral Colonisation - Diarrhoea, oestrogen deficiency, spermicides, antibiotics
Urodynamics - Poor flow/structure
Ascent - Motile flagellae, adherence
Describe the haematogenous route of pathogenesis
Infection of UT through kidneys
What bacterial factors can make UTIs more likely?
Type 1 Fimbriae - Bind to mannose containing epithelial receptors
P- Fimbriae - Bind to Gal-Gal receptors on surface of epithelial cells
What is Tamm Horsfall protein?
A mannose containing protein that binds and allows for the flushing of bacteria
Why is urine anti-bacterial?
Urea is cidal/static
pH is v. low (hippuric acid)
Flow pushes bacteria out
Define secretor status
Some people secrete blood group antigens in their saliva, semun, vaginal secretions etc.
Can trick bacteria
What are the most common pathogens causing UTIs?
Escherichia coli
S. saprophyticus
What are less common pathogens causing UTIs?
Proteus Pseudomonas Klebsiella Enterobacter Enterococcus S. aureus
Define Cystitis
An infection of the lower urinary tract (bladder)
Define Pyelonephritis
An infection of the upper urinary tract (kidneys)
Describe the symptoms of Cystitis
Dysuria, frequency, urgency Suprapubic pain/tenderness Haematuria Fever Cloudy, smelly urine
Describe the symptoms of Pyelonephritis
Loin pain/tenderness
Fever
Nausea/vomiting
+/- lower tract symptoms
What is a occasional presentation of UTIs in children <2?
Failure to thrive due to recurrent infections
What is an occasional presentation of UTIs in the elderly?
Increased confusion
‘Off legs’
What is UTI diagnosis based on?
History/Examination
Urinalysis (mid-stream urine)
What are positive indicators in urine dipstick tests?
Nitrite - Formed by action of bacterial nitrate reductase in enterobacteriae (enterococci do not possess nitrate reductase)
Leucocyte Esterase - Chemical conversion of an ester
What can give false negatives in urine dipstick tests?
Presence of blood
Nitrofurantoin, Rifampicin
Bilirubin
Ascorbic acid
What can give false positives in urine dipstick tests?
Co-amoxiclav
What are M/C signs for UTIs?
Pyuria >100 leukocytes/ml
Culture >10^5 organisms/ml
What is the management of asymptomatic UTIs?
If culture is positive repeat and watch for development of symptoms
IF PREGNANT NEEDS TREATING