Urinary Tract Infection (Cooke) Flashcards Preview

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Flashcards in Urinary Tract Infection (Cooke) Deck (31):
1

UTI and lower urinary tract disease

  • Dogs: UTI common cause urinary tract disease in dogs
  • Cats: UTI NOT common cause urinary tract dz cats

2

Ascending infection

  • primary route
  • adherence and colonization necessary

3

Hematogenous spread

not a major route of infection

4

Bacterial virulence

  1. Adhesions
  2. Capsular antigens
    • inhibit phagocytosis
  3. Hemolysins
    • iron scavenging
  4. Plasmids
    • Promote antibiotic resistance
    • Can be passed from one species to another
  5. Urease
    • proteus, staph, occ klebsiella

5

Host defenses

  • Micturition
  • Anatomy
  • Mucosal barrier
  • Urine

6

Host defense

normal micturition

  • Adequate flow
    • obstruction
  • Complete emptying
    • neurological disease
  • Frequent voiding

7

Host defense

Anatomy

  • urethral length
    • females more susceptible to cystitis than males
  • urethral high pressure zone
    • thought to inhibit urethrovesical reflux
  • urothelium
    • microplicae
  • urethral and ureteral peristalsis
    • proximal to distal
  • Prostatic secretion
    • antibacterial fraction: bactericidal to G- and G+ bacteria
  • Ureterovesical flap valves (absent in ectopic ureters)
    • angled path of ureter through bladder wall
    • closes as bladder fills

8

Host defense

Mucosal Barriers

  • Glycosaminoglycans
    • attract aqueous film
    • non-specific inhibitor of adherence
  • Immunoglobulin production
    • mucosal IgA
  • Cell exfoliation
  • Commensal bacteria
    • out-compete pathogenic bact
    • can be altered with antibiotics

9

Host defense

Urine

  • pH
    • high or low
  • Osmolality
  • Urea
    • normally toxic to bacteria
    • urease producing bacteria get around this
  • Tamm-Horsfall protein
    • can bind fimbriae
  • Low MW carbohydrates
    • may cause detachment and prevent reattachment of E. coli

10

Clinical signs

Lower urinary tract

  1. Pollakiuria
  2. Stranguria
  3. Hematuria
  4. Strong odor
  5. Normal attitude, appetite
    • unless prostatic involvement

11

Clinical signs

Upper urinary tract

  1. variablel and non-specific
  2. anorexia, lethargy
  3. back pain
  4. PU/PD (chronic)

12

Physical exam

Lower urinary tract

  1. Caudal abdominal pain
  2. Thickened bladder: chronic
  3. Palpation may stimulate stranguria
  4. Remainder of exam normal
    • with uncomplicated infection

13

Physical Exam

Upper urinary tract

  1. Depressed
  2. Fever
  3. T-L pain
  4. +/- large kidneys
    • small dogs and cats

14

Diagnostic eval

  • urinalysis (35$)
  • culture and sensitivity (65$)

 

  • CBC (40$)
  • Chem (55$)
  • Rads (150$)
  • Ultrasound (275$)

15

Bloodwork

Lower urinary tract infection

  • CBC
    • normal / stress leukogram
    • leukocytosis
      • not just a bladder infection
  • Chemistry
    • normal
    • +/- azotemia, hyperphosphatemia, hyper or hypokalemia, metabolic acidosis (renal involvement)

16

Urinalysis

  • specific gravity
  • bacteria
    • doesn't localize infection
    • absence doesn't r/o infection
  • casts
    • suggestive renal involvement IF PRESENT
    • = pyelonephritis

17

Culture and Sensitivity

  • Cystocentesis
  • best way to select appropriate antibiotic
    • Ideally lab should report MIC
    • urine antibiotic >/= 4x MIC
  • will not localize infection
  • best way to monitor therapy
    • esp. complicated infections
    • don't really repeat cultures in simple infections

18

Imaging

(complicated/recurrent infections)

  • survey films
  • ultrasound
  • excretory urogram (EU, IVP)
    • renal size and margins
    • dilation of ureters/renal pelvis
    • blunting of diverticuli
    • does not prove active infection

19

Predisposing factors for cystitis

  • incontinence
  • ectompic ureters
  • neuro dz
  • malformed vulva
  • cushings/ other systemic probs
  • neoplasia

*I think these might be complicated UTIs

20

Complicated UTIs

  • All pyelonephritis
  • All prostatitis
  • predisposing factors
  • can't cure unless you correct underlying process

21

Asymptomatic bacteriuria

  • positive culture w/o CS
  • cushings and chemo patients
  • chronic kidney disease
  • occasionally, chronically infected patients

22

Therapy

  • evaluate and treat underlying cause
  • antibiotics
    • based on C & S
      • crucial if infection recurrent OR
      • recent tx with antibiotics (last 4-6 weeks)
    • Empiric therapy while waiting for C & S
      • most common pathogens
      • efficacy of antibiotics
      • concentration in urine (cystitis)
      • concentration in tissue (pyelonephritis)
      • blood:prostate barrier (prostatitis)
  • 10-14 days for uncomplicated bacterial cystitis
  • CS should resolve in 48-72 hours
    • emphasize need to complete full course
  • 4-8 weeks for complicated UTI
    • including pyelonephritis and prostatitis

23

MIxed infection

  • Option 1
    • treat with single antibiotic to which both organisms are sensitive
  • Option 2
    • treat with 2 antibiotics based on C & S
  • Option 3
    • treat predominant pathogen
    • culture during therapy and treat second pathogen if still present

24

Outcome

Cure

  • eradication of microorganisms
  • resolution of CS
  • proven by negative culture

25

Outcome

Presistence

  • failure to eradicate organisms
  • demonstrated by positive culture 3-5 days after initiation of antibiotic therapy
    • same strain
  • R/O inappropriate drug, inadequate dose, frequency, owner/patient compliance
  • May still have initial resolution of CS

26

Outcome

Relapse

  • positive culture ~ 5-7 days after discontinuation of antibiotics
    • same strain
  • similar differentials as for persistence
    • usually indicates inadequate duration of therapy
  • Start looking for complicating factors
    • Consider mixed infection and drug resistance
    • Consider imaging
  • treat for 4-8 weeks

27

Outcome

Reinfection

  • May be difficult to distinguish from relapse or persistence
  • Culture different organism
  • Re-evaluate for predisposing cause
    • systemic disease
    • imaging
    • cytoscopy
  • Base therapy on new culture and sensitivity
  • Frequent re-infection generally due to chronic changes

28

Outcome

Superinfection

  • Develops while receiving antibiotics
  • multi-drug resistant
  • treatment
    • based on C & S
    • Weeks to months

*Don't give dogs with indwelling catheters antibiotics if you can help it

29

Frequent Reinfection

  • Prophylactic antibiotic therapy
    • resolve current infection (negative culture)
    • select drugs excreted in high concentration in the urine
    • treat 1/3-1/2 therapeutic dose given when drug likely to be retained (bedtime)
  • Antiseptic
    • Methanamine hippurate
      • urinary antiseptic
      • requires acidic urine (ammonium chloride: Uroeze)
      • alternative to prophylactic Ab use

30

Real World

First time uncomplicated infection

  • Empiric antibiotic therapy
    • pick one drug
    • treat for 10-14 days
  • If CS persist > 3 days, or if rapid recurrence: CULTURE

31

Summary

  • imbalance between virulence and host defenses
  • culture
  • rational use of antibiotics
    • re-evaluate if no improvements