Pneumonia H2012 -Chapter 257

1. PneumoniaH2012 -Chapter 257 Infection of the pulmonary parenchyma Proliferation of microbial pathogens at the alveolar level and the host's response to those pathogens

2. Most common :aspiration from the oropharynx Many inhaled as contaminated droplets Rarely, hematogenous spread (tricuspid endocarditis) Contiguous extension from an infected pleural or mediastinal space.

3. Mechanical factors Hairs and turbinates of the nares Branching architecture of the tracheobronchial tree(where mucociliary clearance and local antibacterial factors either clear or kill) Gag reflex and Cough Normal flora of the oropharynx, components are remarkably constant

4. Macrophages are extremely efficient at clearing and killing pathogens. Local proteins (e.g., surfactant proteins A and D) have intrinsic opsonizing properties or antibacterial or antiviral activity Once engulfed by the macrophage, the pathogens—even if they are not killed—are eliminated via either the mucociliary elevator or the lymphatics and no longer represent an infectious challenge

5. The host inflammatory response, rather than the proliferation of microorganisms, triggers the clinical syndrome of pneumonia

6. Community-Acquired Pneumonia Bacteria, Fungi, Viruses, Protozoa Newly : Hantaviruses, Metapneumoviruses, Coronavirus responsible for severe acute respiratory syndrome (SARS), and community-acquired strains of methicillin-resistant Staphylococcus aureus (MRSA)

7. Most Common Streptococcus Pneumoniae

8. Typical Streptococcus Pneumoniae Haemophilus Influenzae S. Aureus Klebsiella Pneumoniae Pseudomonas Aeruginosa

9. Atypical (in outpatients) Mycoplasma pneumoniae Chlamydia pneumoniae (in inpatients) Legionella spp Influenza viruses Adenoviruses Respiratory Syncytial Viruses

10. Atypical organisms Cannot be cultured on standard media, nor can they be seen on Gram's stain. Intrinsically resistant to all β-lactam agents and must be treated with a Macrolide, Fluoroquinolone, Tetracycline

11. Virus may be responsible for up to 18% of cases of CAP that require admission to the hospital

12. 10–15% of CAP Polymicrobial often Typical + Atypical

13. الهی ! ما را آن ده که ما را آن به !

14. Microbial Causes of Community-Acquired Pneumonia, by Site of Care Outpatients Non-ICU ICU S. pneumoniaeS. pneumoniaeS. pneumoniae M. pneumoniaeM. pneumoniaeS. aureus H. influenzaeC. Pneumoniae Legionella C. pneumoniaeH. influenzae  Gram-negative Respiratory v.aLegionellaH. influenzae Respiratory virusesa listed in descending order of frequency aInfluenza A and B viruses, adenoviruses, respiratory syncytial viruses, parainfluenza viruses

15. Anaerobes Only when an episode of aspiration days to weeks before presentation pneumonia Alcohol Drug Overdose Seizure Gingivitis often complicated by abscess formation and significant empyemas or parapneumonic effusions.

16. S. aureus Complicate influenza infection MRSA reported as the primary etiologic agent of CAP still relatively uncommon, necrotizing pneumonia MRSA from hospital to the community Genetically distinct strains of MRSA in the community

17. Despite a careful history , physical examination and routine radiographic, the causative pathogen in a case of CAP is difficult to predict In more than One-Half of cases, a specific etiology is never determined Epidemiologic and risk factors may suggest the involvement of certain pathogens

18. Epidemiologic Factors Suggesting Possible Causes of Community-Acquired Pneumonia

19. Alcoholism Streptococcus pneumoniae Oral anaerobes Klebsiella pneumoniae Acinetobacter spp Mycobacterium tuberculosis

20. COPD and/or smoking Haemophilus influenzae Pseudomonas aeruginosa Legionella spp. S. Pneumoniae Moraxella catarrhalis Chlamydia pneumoniae

21. Risk factors for CAP Alcoholism Asthma Immunosuppression Institutionalization ≥70 years

22. Risk factors for pneumococcal pneumonia Dementia Seizure disorders Heart failure Cerebrovascular disease Alcoholism Tobacco smoking COPD

23. CA-MRSA Pneumonia Skin colonization Infection with CA-MRSA

24. P. aeruginosa Bronchiectasis Cystic fibrosis Severe COPD

25. Legionella Diabetes Hematologicmalignancy Cancer Severe renal disease HIV infection Smoking Male Recent Hotel stay or Ship cruise

26. Clinical Manifestations Indolent to Fulminant Mild to Fatal Frequently Febrile with Tachycardia Chills Sweats

27. Cough Nonproductive or Productive Mucoid, Purulent, Blood-tinged

28. If the pleura is involved, : Pleuritic Chest Pain 20% : Gastrointestinal symptoms Nausea, Vomiting, Diarrhea Other symptoms may include Fatigue, Headache, Myalgias, Arthralgias

29. Auscultation Crackles Bronchial breath sounds Pleural friction rub

30. Diagnosis 1:Is this pneumonia? Clinical and Radiographic methods 2:what is the likely etiology? aid of Laboratory techniques

31. Clinical Diagnosis Acute bronchitis Acute exacerbations of chronic bronchitis Heart failure Pulmonary embolism Radiation pneumonitis.

32. Physical Examination Sensitivity and Specificity 58% and 67%

33. Chest radiography is often necessary to differentiate CAP from other conditions Cavitation or Multilobar Occasionally, CXR suggest an etiologic diagnosis. Pneumatoceles :S. aureus Upper-lobe cavitating :Tuberculosis

34. CT is rarely necessary suspected postobstructive pneumonia caused by a Tumor or Foreign body

35. Outpatients Clinical and Radiologic usually all that is done before treatment for CAP since most laboratory results are not available soon enough to influence initial management significantly

36. Rapid Diagnostic Tests Influenza virus infection can prompt specific anti-influenza drug treatment and secondary prevention

37. Etiologic Diagnosis

38. Exposure to birds Chlamydia psittaci

39. Exposure to rabbits Francisella tularensis

40. Local influenza activity Influenza virus S. pneumoniae S. aureus

41. Travel to southwestern United States Hantavirus Coccidioides spp.

42. Dementia, stroke, decreased level of consciousness Oral anaerobes Gram-negative enteric bacteria

43. Severity Cavitation Multilobar

44. Etiologic Diagnosis Pneumatoceles : S. Aureus Upper-lobe cavitating : Tuberculosis

45. CT Rarely necessary Postobstructive pneumonia Tumor or Foreign body

46. Etiologic Diagnosis Except for the 2% of CAP patients who are admitted to the ICU no data exist to show that treatment directed at a specific pathogen is statistically superior to empirical therapy Mycobacterium tuberculosis and influenza

47. Gram's stain main purpose of the sputum Gram's stain is to ensure that a sample is suitable for culture S. pneumoniae, S. aureus, Gram-negative bacteria

48. Adequate for Culture >25 Neutrophils <10 Squamous epithelial cells per low-power field

49. Bacteremic Pneumococcal Pneumonia positive cultures from sputum samples is 50%.

50. Blood Cultures Only ~5–14% of cultures of blood from patients hospitalized with CAP are positive, and the most frequently isolated pathogen is S. pneumoniae