4/17 UTI: iBook Ch 11

Question 1

UTI basic definitions:

Upper Tract Infection v Lower Tract Infection?

Pyelonephritis?

Cystitis?

Prostatitis?

Urethritis?

Answer 1

Upper Tract Infection: infection above the bladder, including kidneys

Lower Tract Infection: infection involving bladder and lower (urethra, prostate)

Pyelonephritis: kidney infection

Cystitis: bladder infection

Prostatitis: prostate infection

Urethritis: urethral infection

Question 2

Ascending route of infection v hematogenous route?

Answer 2

Ascending: infection enters the urinary tract through the urethra

Hematogenous: infection is brought to the kidneys via bloodstream; enters urinary tract that way

Question 3

Urine contamination v urine colonization?

Answer 3

Urine is normally sterile

Contamination: organisms in culture that were introduced from anatomy (foreskin, vulva) or environment – not present in bladder

Colonization: organisms present in urine but not causing sx

Question 4

symptomatic v asymptomatic UTI

Answer 4

There may or may not be symptoms with UTI.

Both will have significant growth of bacteria in urine.

Question 5

symptoms of lower UTI?

Answer 5

dysuria, urgency, frequency, suprapubic pain

Question 6

symptoms of upper UTI?

Answer 6

fever, flank pain (aka costo-vertebral angle pain), nausea, vomiting, sepsis

Question 7

what is meant by complicated UTI?

Answer 7

• obstruction of the urinary tract due to anatomic abnormality or presence of foreign body (stone, catheter)
• functional disruption of flow due to neuromuscular issue
• abnormalities of immune function lowering host depenses, allowing establishment of infection in the urinary tract.

Question 8

acute UTI v chronic UTI? how will they present?

Answer 8

Acute: onset of sx will be a few days prior to pt presentation

Chronic: may be sx or asx, but will have significant #s of bacteria on culture.

Question 9

Recurrent UTIs: re-infection v relapsing infection?

Answer 9

Re-infection: repeated bouts of sx, associated wtih significant bacterial growth from urine. new species of bacteria present with each episode (more common than relapsing infections)

Relapsing infection: repeated episodes, due to the same organism each time. Organism persists despite treatment.

Question 10

Risk factors for ascending UTI in women?

Answer 10

maternal history of UTIs

first UTI prior to age 15

new sex partner w increased activity

diaphragm, condom or spermacide usage

catheters or other instrumentation

Question 11

what usually causes hematogenous seeding of the urinary tract?

Answer 11

usually caused by a bacteremia

Question 12

a urine culture that grows Staph aureus should raise suspicion for what?

Answer 12

presence of staph bacteremia, or other intravascular staph infection such as infective endocarditis

Question 13

what are 2 genetic characteristics that can promote or discourage UTIs?

why are women more predisposed to UTIs?

Answer 13

genetic characteristics: HLA types, blood types. seem to alter the adherence of bacteria within the urinary tract

women: short urethral length seems to encourage UTIs

Question 14

what mechanical effects of urine or urodynamics can cause UTIs?

Answer 14

mechanical: urine flow can be altered by congenital abnormalities

over-distension may lead to inadequate drainage, pooling of urine in bladder, ascension of bacteria into the upper tract

Question 15

a UTI in an infant should prompt what thought?

school age children through middle age: M or F more prone to UTIs?

geriatrics: M or F more prone to UTI?

Answer 15

• Infant UTI: consider congenital abnormality or urinary tract
• childhood thru middle age: women >> men
• geriatrics: men >> women (due to enlarged prostates)

Question 16

what organism causes 95% of UTIs?

What causes a significant % of cystitis in young women?

Answer 16

UTIs: E Coli (bacteria)

cystitis: Staphylococcus saprophyticus

Question 17

name 5 tests used to diagnose a UTI

Answer 17

• urinalysis
• leukocyte esterase reaction
• nitrite test
• urine gram stain
• urine culture

Question 18

describe urinalysis

Answer 18

First step in lab analysis of a UTI

-more than 5-10 WBCs per high powered field indicates infection, as does presence of bacteria in urine sediment.

Question 19

what is a leukocyte esterase reaction?

Answer 19

Dip stick test for UTI

75-95% sensitive

95% specific

Question 20

what is a nitrite test?

Answer 20

dip stick test for UTI

based on the reduction of nitrate by bacteria in the urine. less useful than the leukocyte esterase reaction (also a dipstick test) due to false neg results

Question 21

describe a urine gram stain

Answer 21

diagnostic test for UTI

seeing 1 organism per HPF of un-spun urine –> 10^5 organisms per cc –> significant bacteriuria.

may also provide info on gram pos v gram neg organisms

Question 22

describe a urine culture

Answer 22

diagnostic test for UTI

determines presence of significant organisms in the urine

impt to have a clean sample (clean catch, mid stream) to avoid contamination with periurethral flora.

Question 23

what number of organisms is diagnostic for a symptomatic patient?

what about for an asymptomatic patient?

Answer 23

symptomatic: greater than 10^2 organisms is diagnostic
asymptomatic: greater than 10^5 on two separate days (have to confirm due to potential contamination of sample)

Question 24

what is an indication for imaging of the urinary tract?

Answer 24

Presence of complicated infection, anatomic differences, urodynamic conditions –> imaging (US, CT, MRI).

Can also observe the urinary tract directly via cytoscopy.

Question 25

How might a UTI present in infants/children?

what should I consider?

Answer 25

Might present as failure to thrive, unexplained fever, vomiting.

consider congenital abnormalities

Question 26

Treatment of UTI in women of childbearing age?

Treatment when it is a re-infection?

treatment when it is a relapse?

Answer 26

If re-infection (repeat w different orgs), short course therapy (3d) is indicated. These women may benefit from prophylactic therapy (daily) or self-administration at first symptoms.

If relapse (same org), long course therapy (2-6 weeks) is indicated.

Question 27

Management of UTIs during pregnancy?

Answer 27

Pregnancy: dilatation and altered peristalsis of the ureter. Predisposes -> bacterial ascent.

Screen all preggo women for bacteriuria, even if no symptoms.

Repeat cultures to ensure absence of bacteria.

Question 28

UTIs in young men - what is the usual cause?

Answer 28

usually indicate an STD.

rarely, due to a congenital abnormality.

Question 29

UTIs in the elderly: what is the prevalence?

when do we treat?

what will predispose an elderly patient to UTIs?

Answer 29

relatively high prevalence of UTIs in elderly

We only treat if it is symptomatic: there is no increased morbidity/mortality with asx UTIs in this group.

Foley catheters predispose the elderly to UTIs. remove all catheters as soon as possible.

Question 30

Prostatitis: when should I suspect this?

when should I treat this?

what meds?

Answer 30

Suspect prostatitis in elderly men with recurrent UTIs and presence of prostatic enlargement.

Treat acute prostatitis, 2 or more weeks of antibiotics (they penetrate poorly into the prostate).

Drugs: Trimethoprim-sulfamethoxazole (TMP-SMX) and quinolones are best.

Question 31

Drug to treat Lower Tract UTI in an outpatient?

Answer 31

TMP-SMX

as long as incidence of E Coli resistance to this is < 20% in local region.

Question 32

Antibiotic for Upper Tract UTI in an outpatient?

Answer 32

Empiric ciprofloxacin.

ensure that blood levels obtained following oral ingestion are equiv to levels following IV administration

Question 33

Antibiotics for UTI prophylaxis?

Answer 33

TMP-SMX

trimethoprim

nitrofurantoin

cephalexin

ciprofloxacin

Question 34

Antibiotic for Upper Tract UTI in an inpatient?

Answer 34

amino-glycoside + ampicillin

this combo will cover gram neg organisms and enterococci.