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2010-10-28 19:35:35

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  1. 10-28-b Pneumonia in the abnormal host
    • Pathophysiology: aspiration of oral content into lung
    • Occurs frequently in many adults – as many as ½ adults aspirate small amounts of oral contents during sleep
  2. Healthcare-Associated Pneumonia
    • Conversion of normal flora
    • Within 48-72 hours ill patients converted their normal predominantly anaerobic flora to gram-negative aerobic bacilli:
    • One mechanism may involve the decrease in production of fibronectin in illness, which promotes colonization by the normal flora that bind to the fibronectin:
  3. Definition:
    • >/= 48 hours after admission and excluding infection incubating at time of admission:
    • Indidence 5-10 cases/100 admissions
    • Increased with mechanical ventilation in the ICU setting
    • Duration of ICU stay and mechanical ventilation are major risk factors:
    • Ventilator-Associated Pneumonia (VAP)
  4. Clinical, Radiologic and Lab findings
    • Common things as you’d see with community acquired:
    • Fever
    • Cough
    • Purulent sputum
    • New or progressive pulmonary infiltrate
    • Leukocytosis
    • Gram’s stain, and growth of bacteria in cultures of sputum, tracheal aspirate, pleural fluid, or blood
    • The problem is in the hospital: the symptoms might not be necessarily fro pneumonia, so have confounding factors
  5. Sequelae of healthcare associated pneumonia
    • Healthcare associated pneumonia increases!:
    • More likely to die FROM pneumonia rather that WITH pneumonia
    • Much higher mortality than other common hospital infections
    • You can die from pneumonia even if you kill all the bacteria – because of damage to the lungs
  6. Pathophysiology
    • Selection of resistant organisms:
    • Use of antibiotics in hospitals sets the epidemiologic stage for multiply-resistant gram negative pathogens and possibility of spread from patient to patient to staff, to patient, and medical instruments
  7. Aspiration pneumonia vs. pneumonitis
    • Not all aspiration are pneumonia:
    • Episodes of aspirations pneumonitis generally resolve within 48-72 hrs unless they become infected
    • Greater risk >/= years of age, obesity, COPD, etc.
  8. Risk Factors for Aspiration
    • Almost always because of anesthesia
    • Surgery
    • Instrumentation of the respiratory tract
    • Anesthesia
    • Use of narcotics and sedative
  9. Microbiology of healthcare associated pneumonia
    • Early healthcare associated pneumonia
    • S. pneumoniae, H. Influenzae and oxacilin sensitive, S. aureus and the gram-negative pathogens - e.coli, klebsiella spp and proteus spp
    • Many of these see in community, not that much resistance
    • Don’t want to treat because risk leaving resistant bacteria, will resolve
  10. Late onset healthcare associated pneumonia
    • P. aeruginosa, oxacillin-resistant S. aureus, and Acinetobacter spp.:
    • Other gram negative strans that are usually multi-antibiotic-resistant
    • Anaerobes are not routinely seen
  11. Pseudomonas aeruginosa
    • Oxydase positive and a non-lactose fermenting:
    • Small, thin Gram negative rods
    • Ubiquitous in soil and water
    • Generally considered an aerobic GNR but will grow anaerobically if NO3 is present as an electron receptor
  12. Pseudomonas pneumonia
    • Pseudomonas aeruginosa is predominantly a healthcare-associated pathogen or immunocompromised host:
    • Primary pneumonia results from aspiration of colonized secretions
    • Progression to pneumonia may be rapid with severe illness and life-threatening infection
    • CXR typically show bronchopneumonia either unilateral or bilateral
  13. Chronic pseudomonas infection
    • Chronic infection of the lower respiratory tract is generally caused by alginate-producing, mucoid strains of P. aeruginosa:
    • Most frequently with cystic fibrosis and also some patients with AIDS
  14. Treatment of pseudomonas
    • Antipseudomonal beta-lactam (piperacillin, aztreonam, imipenem, cefepime, or ceftazidime):
    • AND:
    • Aminoglycoside – such as gentamicin, tobramycin, or amikacin:
    • Aminoglycosides have poor penetration into pulmonary secretions and are less effective in acidic environment of purulent secretions
    • Quinolones – ciprofloxacin have excellent activity and may be added to the regimen or replace the aminoglycosides:
  15. Burkholderia
    • Used to be B. cepacia:
    • Seen in patients with cystic fibrosis near the end stage of disease: and after multiple antibiotic treatment
    • Also need always a travel history
  16. Strenotrophomonas Maltophilia
    • Seen in patients treated with multiple antibiotics:
    • Intrinsically resistant to the carbapenems like imipenem because of the zinc metallo-beta-lactamase:
    • Frequently only sensitive to trimethoprim-sulfamethoxazole:
  17. Acinetobacter
    • Another in the line of highly resistant gram-negative pathogens:
    • May be sensitive to only one or nor antibiotics
    • Seen in troops in Iraq, especially in wounds. Unclear why it is so common there:
  18. Treatment recommendations: early hospital acquired pneumonia
    Therapy similar to community acquired therapy, with a little bit more gram negative activity
  19. Treatment Recommendations: early hospital acquired pneumonia
    • Consder highly resistant bacteria.
    • Cephalosporin, carbipenem,
    • An anti-beta lactam
    • And aminoglycoside
    • AND if have MRSA, then Vancomycin
    • Want to have something that covers pseudomonas: an anti-pseudomonas beta lactam + aminoglycoside or a quinolone
    • To cover legionella: respiratory fluoroquinolone or a macrolide