UTI Flashcards
Is the urethra sterile?
– the urethra is NOT sterile (whilst urine in the bladder is sterile, the urine coming out the urethra is not sterile)
What happens if you fins squamous cells in an MSU
o Squamous epithelial cells are found at the end of the urethra
o If squamous epithelial cells are found in an MSU sample, the sample has not been taken properly
Is bacteruria bad?
o Asymptomatic bacteriuria is NOT usually relevant
o However, asymptomatic bacteriuria with coliform is significant in PREGNANCY
Difference between an uncomplicated and complicated UTI?
o Uncomplicated: infection is a structurally and neurologically normal urinary tract
o Complicated: infection with functional or structural abnormalities (including indwelling catheters and calculi)
Groups of patients where it is regarded as complicated?
Men Pregnant women
Children (not young girls) Patients in a healthcare- or HC-associated settings
Most common causes of UTIs?
• Most Common = Escherichia coli
o Staphylococcus saprophyticus (coagulase -ve staphylococcus)
2nd most common cause of UTI in younger women
Recurrent causes- non E coli
Causes of obstruction leading to UTIs?
Mechanical
Extrarenal- valves, calculi, stenosis
Intrarenal- nephrocalcinosis, PKD
Neurogenci- DM, poliomyelitis
How Vesicoureteric Reflux (VUR) causes infection
Perpetuate infection by maintaining a residual pool of infected urine in the bladder after voiding
The reflux can result in scarring of the kidneys
Haematogenous route of infection the kidney
o Kidney is a frequent site of abscesses in patients with S. aureus bacteraemia or endocarditis
o Infection of the kidney with Gram-negative bacilli rarely occurs by the haematogenous route
Symptoms of UTI in children
o Failure to thrive
o Vomiting
o Fever
Symptoms of UTI in adults
o Frequency
o Dysuria
o Abdominal or flank pain
Upper vs lower UTI symptoms
Lower: irritation of urethral & vesical mucosa frequent/painful urination of small amounts of turbid urine
o Suprapubic heaviness or pain
o Gross haematuria
o Fever absent
Upper: Lower symptoms May precede UUTS by 1-2 days plus
o Fever (sometimes with rigors)
o Flank pain
Older patients symptoms?
Atypical
Abdo pain, mental state change
Investigations of UTIs
o Urine dipstick
o MSU for urine MC&S
o Bloods – FBC, U&E, CRP
Interpreting Urine Culture Results:
o Culture of single organisms >105 CFUs/mL + urinary symptoms diagnostic of UTI
o Culture of E. coli or S. saprophyticus organisms >103 CFUs/mL + urinary symptoms diagnostic of UTI
White cells >104/mL (or 107/L) = inflammation
Pyuria is usually ABSENT in children
Mixed growth reduces the significance of culture (suggests contamination)
Epithelial cells present in high numbers suggest a failed MSU technique
What does sterile pyuria suggest
o If sterile pyuria (raised WCC but no growth on culture), consider:
Prior treatment with antibiotics (MOST COMMON)
Calculi
Catheterisation Bladder neoplasm
TB STI (Chlamydia trachomatis)
What colour represents what species in a culuture?
Pink E. coli
Blue other coliforms
Light blue gram +ve
Usual ABx used for treatment
normally Trimethoprim/Nitrofurantoin/Cephalexin in for uncomplicated UTIs for 3 days
o No nitrofurantoin in pregnancy as associated with haemolysis
7 days of treatment
History of previous urinary tract infection caused by antibiotic-resistant organisms
>7 days of symptoms
Fungal infections causes in the UT and the treatment
o Most Candida UTIs occur in patients with indwelling catheters
o Management removal of the catheter (antifungals no more effective than no therapy)
Management of pyelonephritis
o Prior to culture results amoxicillin (or ciprofloxacin)
o Culture results co-amoxiclav ± gentamicin (broad spectrums)
Complications of pyelo
o Perinephric abscess
o Chronic pyelonephritis scarring, chronic renal impairment
o Septic shock
o Acute papillary necrosis
