Session 10 B UTIs Flashcards
Urinary tract is normally
Sterile and resistant to bacterial colonisation
Urinary tract defences
Emptying of bladder during micturition
Vesico-ureteral valves
Immunological factors
Mucosal barriers
Urine acidity
Ascending colonisation of bacteria from urethra can cause
Cystitis: bladder
Pyelonephritis: kidney
Risk factors for UTIs
Causative agents for UTIs
Most caused by coli forms (gram negative organisms)
E. Coli is most common
E. coli stands for
Escherichia coli
Features of E. coli
Flagellar: movement
Pili: attachment
Capsular polysaccharide: colonisation
Haemolysin, toxins: damages host membranes and causes renal damage
Clinical presentation of Cystitis (lower UTI)
Clinical presentation of Pyelonephritis (upper UTI)
Dysuria may be due to other causes of inflammation (urethritis) such as
STIs
Post sexual intercourse
Contact with irritants
Symptoms of menopause, atrophic vaginitis or vaginal atrophy
Define an uncomplicated UTI
Infection by a usual organism
Patient with normal urinary tract
Normal urinary function
Factors that predispose to persistent infection, recurrent infection or treatment failure
Abnormal urinary tract
Virulent organism (staph aureus)
Impaired host defence (immunosuppression, poorly controlled diabetes)
Impaired renal function
Suspected pyelonephritis
Investigations for UTI
Urine culture, dipstick, visual inspection
There is no need for urine culture in
Healthy, non-pregnancy women of child bearing age
Culture in complicated UTI
Mid-stream urine- cleansing not required, ideally holding labia apart in women
Clean catch in children
Culture urine within 4 hours of collection, refrigerate or use boric acid preservative
What can be used as an aid to diagnosis
Urine dipstick
urine dipstick is not useful in
Patient over 65 as commonly have asymptomatic infections
Catheterised patients
Urine dipstick is useful if patient presents with 1 of the following
Dysuria
New nocturia
Cloudy urine present
If negative for nitrites, positive for LE, suggests
Staphlococcus saprophyticus
Imaging of urinary tract
Considered in all children with UTI
Valuable in septic patients to identify renal involvement (i.e. pyelonephritis)
Treatment of UTI
Increased fluid intake
Regular analgesia
Address underlying disorders
Antibiotics e.g. Trimethoprim
Antibiotic treatment of UTIs
3 day course for uncomplicated
5-7 day cause for complicated lower UTI e.g. pregnant, male, underlying disorders
Treatment of cystitis
Nitrofurantoin, trimethoprim, pivmecillinam or fosfomycin
Treatment for uncomplicated cystitis
3 day course as effective as 5-7
Limiting prescription to 3 days reduces selection pressure for resistance
Treatment for complicated UTI e.g. male, pregnant, catheter
5-7 day course
General Treatment of pyelonephritis/septicaemia
7-10 day course
Use agent with systemic activity (NOT nitrofurantoin, fosfomycin)
Specific treatment for pyelonephritis
Possibly IV initially unless good oral absorption and patient well enough
Co-amoxiclav
Ciprofloxacin (7 day course)
Gentamicin (IV only, nephrotoxic)
