Urinary tract infection

Question 1

what is the most common cause of UTI

Answer 1

E coli

Question 2

what other organisms cause UTI

Answer 2

o Proteus mirabilis
o Klebsiella aerogenes
o Enterococcus faecalis
o Staphylococcus saprophyticus (coagulase -ve staphylococcus)
 2nd most common cause of UTI in younger women
 Virulence factors (P-fimbriae) that allow adherence to the epithelium
o Staphylococcus epidermidis:
 UTI in the presence of prosthesis (e.g. procedures or long-term indwelling catheter)

Question 3

what organism is a common cause of UTI in prosthesis

Answer 3

staph epidermis

Question 4

what is a common cause of recurrent uti

Answer 4

non e coli organisms like proteus, pseudomonas, klebsiella

Question 5

what are the antibacterial host defences in urinary tract

Answer 5

o Urine (osmolality, pH, organic acids)
o Urine flow and micturition
o Urinary tract mucosa (bactericidal activity, cytokines)

Question 6

how can causes of urinary obstruction be divided into 3 chategories

Answer 6

	Mechanical 
	Extrarenal:
•	Valves, stenosis or bands 
•	Calculi
•	BPH
	Intrarenal
•	Nephrocalcinosis				Uric acid nephropathy 
•	Analgesic nephropathy 			PKD 
•	Hypokalaemic nephropathy 		Renal lesions of SCD
	Neurogenic malfunction:
•	Poliomyelitis 				Tabes dorsalis
•	Diabetic neuropathy			Spinal cord injuries

Question 7

upper uti symptoms

Answer 7

o	Lower UT symptoms / LUTS [frequency, urgency, nocturia, dysuria] 	/ 	FUND HIPS
	May precede UUTS by 1-2 days 
	Symptoms may vary greatly 
o	Fever (sometimes with rigors)
o	Flank pain

Question 8

lower UTI symptoms

Answer 8

o Bacteria  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 (in infections confined to lower UT)

Question 9

symptoms in older patients

Answer 9

o Vast majority will be ASYMPTOMATIC
o Diagnosis difficult as non-infected older patients often experience frequency, dysuria, hesitancy & incontinence
o Symptoms of upper urinary tract infections are often atypical (e.g. abdominal pain, confusion)
o Advice is NOT to jump to urine dipstick as it may lead you down the wrong route and lead to excess abx

Question 10

investigations - leucoytes positive nitrites negative

Answer 10

only start abx if clinical evidence of UTI, cause may be non coliform bacterium e.g. not e coli

Question 11

in sexual active young men what organism should be considered

Answer 11

clamydya

Question 12

when should lab testing for MC +S be done

Answer 12

o Pregnancy (because asymptomatic bacteriuria is an issue)
o Suspected UTI in children
o Suspected UTI in men
o Suspected pyelonephritis
o Catheterised patients
o Failed antibiotic treatment (resistance)
o Abnormalities of the genitourinary tract
o Renal impairment

Question 13

if there is sterile pyuria - raised wcc but no growth on culture what should be considered

Answer 13

sterile pyuria (raised WCC but no growth on culture), consider:
 Prior treatment with antibiotics (MOST COMMON) Calculi
 Catheterisation Bladder neoplasm
 TB STI (Chlamydia trachomatis)

Question 14

management of pyelonephritis

Answer 14

• Management (requires aggressive treatment):
o Prior to culture results  amoxicillin (or ciprofloxacin)
o Culture results  co-amoxiclav ± gentamicin (broad spectrums)

• Imaging (for 1st case in men, and 2nd case in women):
o Calculi
o Structural cause