UTI Flashcards
UTI Predisposing Factors
- Obstruction: BPH, urethral structure, tumors, calculi, bladder diverticula
- Incomplete emptying: SCI, DM, stroke, neuropathies
- Reflux: over-distension, congenital, vesicoureteral reflux
- Intercourse: diaphragms, spermicides
- Urinary catheterization
- Pregnancy
- Previous UTI
Host Defense
- Normal urinary tract: urine pH, osmolality, high [urea/organic acid], and prostate secretion
- Stimulation of micturition by bacteria
- Anti-adherence: Mucopolysaccharide, Tamm-Horsfall protein, immunoglobulins
- Inflammatory response
- Vaginal flora, estrogen
Common Pathogens
- E. Coli
- K. pneumoniae
- Proteus spp
- P. aeruginosa
- S. saprophyticus
- Enterococcus spp.
Virulence Factors
- Organism’s degree of pathogenicity
- Adhesion mechanisms like fimbriae
- Hemolysin: ruptures RBCs
- Aerobactin allow organism to absorb iron
Fimbriae
- Hair like structure allowing binding to cell wall
- Mannose resistant, P-fimbriae binds to uroepithelial cells and is more likely to cause kidney stones
Routes of Infection
- Hematogenous: uncommon, bacteria carried elsewhere in the body through the blood and seeds infection
- Ascending: common, colonization of urethra with fecal flora leading to infection
- Lymphatic: unknown incidence, limited amount of data
Diagnosis
- Based on presence of symptoms and supported by urinalysis or urine culture
- Asymptomatic UTI: presence of bacteria without symptoms
Cystitis UTI symptoms
- Lower UTI
- Dysuria
- Urgency
- Frequency
- Suprapubic tenderness
Pyelonephritis UTI Symptoms
- Upper UTI
- Flank pain
- Fever
- Nausea
- Vomiting
- Malaise
- CVA tenderness
Catheter Associated UTI Symptoms
- Compatible with UTI + urethral/suprapubic/intermittent catheterization
- > 10^2 cfu/mL of bacteria in fresh catheter urine culture
Clean Catch
- Preferred urine specimen collection method
- Least invasive
- Discard first 20-30 mL voided
- Requires clean urethral opening
Alternative Urine Collection
- Catheterization: for uncooperative or unable to void patients
- Suprapubic bladder aspiration: used in newborns, infants, paraplegics, and seriously ill patients when other methods have failed
Urinalysis
- Nitrates: present when bacteria reduces urinary nitrates
- LCE: produced by neutrophils
- Squamous cells: >= 20 then sample likely contaminated
- WBCs: shows GU inflammation and if >= 10 then may indicate a UTI
- Bacteria/yeast: could be normal flora, contaminant, or sign of UTI
Urine Culture
- Most reliable way to diagnose UTI
- Quantity of colony forming units to confirm infection: >= 10^5 of single strain
Cranberry
- No conclusive data that it prevents UTI
- Potential benefit may be more related to hydration vs cranberry itself
Asymptomatic Bacteria
- Only treat if pregnant or with pending GU procedure
- Options: Macrobid, Augmentin, Cephalexin, Fosfomycin, or Bactrim
Asymptomatic Bacteria + Drug Doses
- Macrobid: 100 mg PO BID x 5-7 days (don’t use if at term, 1st trimester, or pyelonephritis)
- Augmentin: 875/125 mg PO BID x 5-7 days
- Cephalexin: 500 mg PO BID x 5-7 days
- Fosfomycin: 3g PO as single dose (don’t use if pyelonephritis suspected)
- Bactrim 1 DS PO BID x 3-7 days (avoid in 1st or late 3rd trimester)
Uncomplicated Cystitis
- Don’t need initial urine culture
- Health women: 12-45 y.o., premenopausal, not preggo, no structural abnormalities
Uncomplicated Cystitis Treatments
- Macrobid: 100 mg PO BID x 5 days
- Bactrim: 1 DS tablets PO BID x 3 days
- Fosfomycin: 3g powder PO x 1 dose
- Augmentin: 500/125 mg PO TID x 5 days
- Cefdinir: 300 mg PO BID x 5 days
- Cefpodoxime: 100 mg PO BID x 5 days
- Ciprofloxacin: 250 mg PO BID x 3 days
- Levofloxacin: 250 mg PO q24h x4days
What NOT to use empirically for Uncomplicated Cystitis
- Amoxicillin
- Ampicillin
Complicated Cystitis
- All adults who don’t meet uncomplicated criteria
- Usually from structural abnormality
- Treatment depends on severity, is the same as pyelonephritis
- Duration: 7-10 days
Mild-Mod. Pyelonephritis
- Fever and CVA tenderness
- May treat with oral regimens and outpatient
- Obtain UA, urine, and blood cultures
Mild-Mod. Pyelonephritis Treatments
- Cipro: 500 mg PO BID x 7 days
- Levofloxacin: 500 mg PO daily x 7 days
- Bactrim: 1 DS PO BID x 3 days
- Augmentin: 875/125 mg PO BID x 10-14 days
- Cephalexin: 500 mg PO QID x 10-14 days
- Ceftriaxone: 1-2g IV daily
Severe Pyelonephritis
- Fever > 38.3 C
- Severe flank pain
- N/V, dehydration, hemodynamic instability, sepsis
- Treat inpatient with IV
- Obtain UA, urine, and blood cultures
- Can switch to PO once afebrile x 24-48 hours
- Duration: 10-14 days
- Repeat cultures should be considered after treatment to ensure resolution of infection
- Adjust treatment based on culture results
Severe Pyelonephritis Parenteral Treatment
- Zosyn: 4.5g IV q6h
- Cipro: 400 mg IV q12h
- Levofloxacin: 500 mg IV q24h
- Ceftriaxone: 1g IV q24h
- Cefepime: 2g IV q8h
Severe Pyelonephritis Oral Treatment
- Cipro: 500 mg PO BID
- Levofloxacin: 500 mg PO daily
- Bactrim: 1 DS PO BID
CAUTI
- Catheter-Associated UTI
- Plastic tubing promotes bacteria growth and formation of biofilms
- Urine samples from old catheters won’t give accurate cultures
- Change catheter every 2 weeks
- Treat based on pathogens/susceptibilities
- Duration: 7 days if prompt resolution of symptoms or 10-14 days for delayed response
Adjuvant Therapy
- Phenazopyridine HCl
- OTC: anesthetic and analgesic to relieve symptoms
- 100-200 mg TID after meals x 2 days + APPROPRIATE ABX
- Secretions may change to a red-orange and permanently stain clothing
Relapse
- Same organism within 2 weeks after completion
- Obtain sample and culture for susceptibility
- Evaluate resistance, adherence, and other sources
Recurrence
- > 2 weeks after treatment or after documented sterile culture
- Defined as >= 2 UTIs within 6 months or >= 3 UTIs in a year