Pneumonia

1. Pneumonia

3. Disease Definition • Pathological • Clinical • infiltrate(s) on CXR is need • CAP • HAP • VAP • HCAP • Typical and Atypical

5. Pathogenesis • HOST DEFENSES • Routes of Infection • Gross aspiration • Microaspiration • Aerosolization • Hematogenous spread from a distant infected site • Direct spread from a contiguous infected site

6. PATHOLOGY • Lobar Pneumonia • Bronchopneumonia • Interstitial Pneumonia • Miliary Pneumonia

7. Risk Factors • Impaired Host defense • Anatomical defects • such as obstructed bronchus, bronchiectasis, or sequestration • Alcoholism , asthma , immunosuppression , age of >70 , dementia, seizures, CHF, CVD, alcoholism, COPD , chronic illness, smoking, and passive smoking

8. Epidemiology • Extremes of age • During the winter months • Rates of pneumonia are higher for men than for women and for black than for white persons

9. ETIOLOGY • Common respiratory pathogens • S. pneumoniae, H. influenzae, S.aureus, Moraxella catarrhalis • C. pneumoniae, M. pneumoniae Legionella spp. • Influenza viruses, adenoviruses, and respiratory syncytial virus

10. S. pneumoniae • meta-analysis of CAP 1966 – 1995 • S. pneumoniae • 66% of 7000 cases • 66% of fatalities Fine JAMA 1996:275;134

11. Atypical Pathogens • M. pneumoniae, C. pneumoniae and Legionella sp. ranked 2nd 3rd and 4th of over 2700 hospitalized CAP patients with a definite etiologic diagnosis. • Marston et al Arch Intern Med 157:1709,1997

14. CLINICAL MANIFESTATIONS • Symptoms • Signs • Examination • Auscultatory findings

15. Severity • CURB • CURB 65 • PORT

16. Mortality • P. aeruginosa >50% • Klebsiella spp., E. coli, S. aureus, and Acinetobacter spp. 30 to 35% • Serotype 3 pneumococcus is associated with a much higher mortality rate than serotype 1 • M serotypes 1 and 3 of group A Streptococcus

17. Mortality • The in-hospital mortality rate from pneumonia is ~8%. • The most common causes: • respiratory failure • heart disease • Infections • Half of deaths are related to pneumonia, and the other half are due to comorbid illnesses.

18. DIAGNOSIS • CXR • CT scan • Sputum smear • Sputum culture • Serology • Ag study • PCR • Blood Culture

20. Outpatient or Inpatient • CURB-65 criteria:(confusion, uremia, respiratory rate, low blood pressure,age 65 years or greater) • For patients with CURB-65 scores 2, hospitalization is usually warranted.

22. ICU admission decision • 2 major criteria (need for mechanical ventilation and septic shock), • Minor criteria (respiratory rate, 130 breaths/min; arterial oxygen pressure/fraction of inspired oxygen (PaO2/FiO2) ratio <250; multilobar infiltrates; confusion; blood urea nitrogen Level>20 mg/dL; leukopenia resulting from infection; thrombocytopenia;hypothermia; or hypotension requiring aggressive fluid resuscitation. • The presence of at least 3 of these criteria suggests the need for ICU care

23. CXR resolve • Age • Co morbidity • Lung disease • Pathogen • 4-8 weeks

24. Resistant pneumococci • To Penicillin MIC<0.06 0.12<MIC<1 MIC >2 mg/mL • To Macrolides • To Tetracyclines • To FQ

28. Duration Patients with CAP should be treated for • a minimum of 5 days • should be afebrile for 48–72 h • should have no more than 1 CAP-associated sign of clinical instability before discontinuation of therapy A longer duration of therapy may be needed if initial therapy was not active against the identified pathogen or if it was complicated by extrapulmonary infection, such as meningitis or endocarditis.

30. PO Therapy & Discharge Switched from intravenous to oral therapy when • they are hemodynamically stable • Improving clinically • are able to ingest medications • have a normally functioning gastrointestinal tract. Patients should be discharged as soon as • they are clinically stable • have no other active medical problems • have a safe environment for continued care Inpatient observation while receiving oral therapy is not necessary.

31. Complications • Pleural effusion • Empyema • Lung abscess • Recurrent pneumonia • No response

32. Aspiration Pneumonia • The usual causes of aspiration pneumonia in the elderly are Enterobacteriaceae, S. aureus, S. pneumoniae, and H. influenzae. • In the setting of aspiration of oropharyngeal contents and poor dental hygiene, anaerobic bacteria may be present, and lung abscess is not an uncommon complication. Particulate matter may be aspirated, with consequent mechanical obstruction of the airway.

34. NOSOCOMIALPNEUMONIA • Acquired by a patient in the following settings: • in a hospital or long-term-care facility after being admitted for >48 hours or • <7 days after a patient is discharged from hospital ( patient’s initial hospitalization should be 3 days duration )

35. Risk Factors • Host factors ( e.g. extremes of age, severe underlying disease ) • Colonization by gram-negative microorganisms • Aspiration or reflux • Prolonged mechanical ventilation • Factors that impede adequate pulmonary toilet

36. Nosocomial Bacterial Pneumonia - Etiology • Gram-negative enteric bacilli (predominant) • Gram-positive cocci, including: Staphylococcus aureus ( e.g., MRSA ), Streptococcus pneumoniae • Anaerobes • Others

40. Prevention • Inactivated influenza vaccine • Pneumococcal polysaccharide vaccine • Respiratory hygiene measures, including the use of hand hygiene and masks or tissues for patients with cough, should be used in outpatient settings and EDs as a means to reduce the spread of respiratory infections.