UTIs

Question 1

Complicated vs uncomplicated UTI

Answer 1

Uncomplicated: normal renal tract structure and function

Complicated: structural or functional abnormality of genitourinary tract e.g. obstruction, catheter, stones, neurogenic bladder, renal transplant

Question 2

Organisms associated with UTIs

Answer 2

• Usually anaerobes and gram negative bacteria from vaginal and bowel flora
• E.coli in 75-90% of cases in the community, less so in nosocomial UTI
• Staphylococcus saprophyticus in 5-10%
• Also proteus mirabilis and klebsiella pneumonia

Question 3

Investigation of UTI: women

Answer 3

1st line investigation to order:

• Urine dipstick – nitrite and leukocyte esterase positive 
• Urine microscopy – bacteria, WBC, possibly RBC 
• Urine culture and sensitivity – growth of >10^5 CFU/ml 

Investigations to consider:

• Post void residual (PVR) – indicates urinary retention (>100mL)
• Renal US – kidney stone; hydronephrosis; renal abscess; renal scarring 
• Abdominal/pelvic CT scan – kidney or bladder stone
• Cystoscopy – tumour, bladder stone, foreign body, diverticulum 

Question 4

UTI management

Answer 4

Acute, uncomplicated:

• 1st line – oral antibiotic therapy 
• Nitrofurantoin 100mg PO (modified release) BD for 5 days 
• Trimethoprim 160/180 mg PO BD for 3 days 

Acute, complicated:

• 1st line = IV antibiotic therapy 
• Gentamicin 1 to 1.5 mg/Kg IV every 8 hours for 7 to 14 days

Question 5

Investigation of UTI in men

Answer 5

1st line investigation to order:

• Urine dipstick – nitrite and leukocyte esterase positive 
• Urine microscopy –leukocytes and/or bacteria 
• Urine culture – growth of >10^2 CFU/ml 

Investigations to consider:

• Gram stain – bacteria 
• CT renal tract – perirenal abscess, urinary calculi, or tumours 
• KUB – urinary tract stone, abscess 
• Ultrasound – rules out obstruction 
• IVU (intravenous urogram) – rules out obstruction