Community-acquired pneumonia (CAP) is a common infectious disease worldwide and a major cause of mortality and morbidity. The document discusses definitions, etiology, risk factors, diagnosis, and treatment recommendations for CAP according to guidelines from IDSA/ATS. Key points include common bacterial and atypical pathogens causing typical and atypical CAP; use of severity assessment scores to determine hospitalization and ICU needs; recommendations for empirical antibiotic therapy based on patient factors; and considerations for MRSA coverage and broad-spectrum therapy.

2. BY
Dr.
Assuit University
Lecturer of Chest Diseases

4. • Richard G. Wunderink and Grant W.
Waterer. Community-Acquired Pneumonia. N
Engl J Med 2014;370:543-51. DOI:
10.1056/NEJMcp1214869
• Infectious Diseases Society of America (IDSA)
/American Thoracic Society Consensus (ATS)
Guidelines on the Management of Community-
Acquired Pneumonia in Adults. Clinical Infectious
Diseases 2007; 44:S27–72.

5. The antibiotic regimens advocated by a
collaboration between the Infectious Diseases
Society of America (IDSA)/American Thoracic
Society (ATS) in 2007 and the British Thoracic
Society (BTS) in 2009.

7. Community-acquired pneumonia (CAP)
is one of the most common infectious
diseases and is an important cause of
mortality and morbidity worldwide.

8. 3.5 million cases/year
At least 1 million hospitalizations/year
9th leading cause of infectious death in
US
30 day morality for hospitalized patients
is up to 23%
$17 billion/year in healthcare costs in US

9. 1.Definition
2.Aetiology
3.Risk stratification
4.Diagnosis
5.Treatment

11. Pneumonia is acute infection of the lung
parenchyma.
Community-acquired pneumonia (CAP):
Refers to pneumonia acquired outside of
hospitals in the community and not acquired in a
hospital, long-term care facility, or other recent
contact with the health care system.

13. Typical community-acquired pneumonia
The term “typical” CAP refers to a bacterial
pneumonia caused by pathogens such as S
pneumoniae, H influenzae, and M catarrhalis.
Patients with typical CAP classically present
with fever, a productive cough with purulent
sputum, dyspnea, and pleuritic chest pain.

14. Characteristic pulmonary findings on physical examination
include the following:
 Tachypnea
 Rales heard over the involved lobe or segment
 Increased tactile fremitus, bronchial breath sounds, and
egophony may be present if consolidation has occurred.
 Decreased tactile fremitus and dullness on chest percussion
may result from parapneumonic effusion or empyema.

15. Atypical community-acquired pneumonia
The clinical presentation of so-called “atypical”
CAP is often subacute and frequently indolent. In
addition, patients with atypical CAP may present
with more subtle pulmonary findings, nonlobar
infiltrates on radiography, and various
extrapulmonary manifestations (eg, diarrhea,
otalgia).

16. Atypical CAP pathogens include the following:
 Mycoplasma pneumoniae
 Chlamydophila ( Chlamydia) pneumoniae
 Legionnaires disease (Legionella pneumophila)
 Respiratory viruses :Influenza A and B, Rhinovirus
and Respiratory syncytial virus.

17. Most common etiologies of community-acquired
Patient Setting Common Pathogens
Outpatients
<60 yr
No comorbid diseases
Streptococcus pneumoniae
Mycoplasma pneumoniae
Haemophilus influenzae
Chlamydia pneumoniae
M catarrhalis
Respiratory Viruses
>65 yr or with comorbid disease or
antibiotic therapy within last 3 mo
S. pneumoniae (drug-resistant)
M. pneumoniae
C. pneumoniae
H. influenzae
Viruses
Gram-negative bacilli
S. aureus

18. Most common etiologies of community-acquired
Patient Setting Common Pathogens
(non ICU)Inpatients
S. pneumoniae
M. pneumoniae
C. pneumoniae
H. influenzae
Legionella species
Aspiration
Respiratory virusesa
(ICU)Inpatients S. pneumoniae
Staphylococcus aureus
Legionella species
Gram-negative bacilli
H. influenzae

20. Risk factors of CAP:
▸ Age
▸ Alcoholism
▸ Smoking
▸ Underlying diseases
▸ Chronic heart disease
▸ Chronic renal disease
▸ Chronic liver disease
▸ Chronic respiratory disease
▸ Metabolic disease
▸ CNS disease

21. Risk factors of CAP:
▸ Immunosuppression
▸Autoimmune diseases receiving steroid or
immunosuppressive therapy or biological
therapy
▸ Cancer with immunosuppressive treatment
▸ Waiting list for solid-organ transplantation
(with or without immunosuppressive treatment)
▸ Asplenia/splenic dysfunction
▸ Primary immunodeficiencies
▸ HIV

22. There is wide variation in admission rates for community
acquired pneumonia so objective scoring systems were
created to help standardize decision making and risk
stratification. The Pneumonia Severity Index (PSI) is
validated but requires a computer to calculate. The CURB
65 score is easier, with 1 point each for.

23. Pneumonia Severity Index

26. severe community-acquired pneumonia:
Several criteria have been proposed to define severe CAP.
Most case series have defined it simply as CAP that
necessitates ICU admission

27. Criteria for severe community-acquired
pneumonia:
Minor criteria
1. Respiratory rate ≥30 breaths/min
2. PaO2/FiO2 ratio ≤ 250
3. Multilobar infiltrates
4. Confusion/disorientation

28. 5.Uremia (BUN level ≥ 20 mg/dL)
6.Leukopeniac (WBC count<4000 cells/mm3)
7.Thrombocytopenia (platelet count < 100,000 cells/mm3)
8.Hypothermia (core temperature < 36C)
9.Hypotension requiring aggressive fluid resuscitation

29. Major criteria
• Invasive mechanical ventilation
• Septic shock with the need for vasopressors

30. Diagnosing Pneumonia: How
Much Testing Is Needed?

31. No diagnostic testing beyond chest radiograph is necessary for
most people with community acquired pneumonia, especially
outpatients or those hospitalized with less severe disease.
Among people with more severe pneumonia, there is disagreement
among experts as to how much diagnostic testing is indicated

32. Purulent sputum is characteristic of pneumonia caused by bacterial community-acquired
pneumonia (CAP) pathogens and is not usually a feature of pneumonia caused by atypical
pathogens. Blood-tinged sputum may be found in patients with pneumococcal pneumonia,
Klebsiella pneumonia, or Legionella pneumonia.
Rales are heard over the involved lobe or segment. Consolidation may be accompanied by
an increase in tactile fremitus, bronchial breathing, and egophony.

33. Investigations
Blood culture: These authors recommend blood culture only for patients
admitted to the ICU or with healthcare associated pneumonia, or who have
cirrhosis or lack a spleen.
Sputum culture: For intubated patients, or those with productive cough
with severe pneumonia or HCAP or severe COPD or structural lung disease
(e.g. bronchiectasis).

34. During influenza season, testing for influenza is indicated for all
patients with pneumonia, with treatment with oseltamivir if flu testing
is positive (or empirically pending influenza test results).
Urinary pneumococcal and Legionella antigen testing is recommended
for people with severe or health care associated pneumonia.
Pleural fluid should be always cultured, if it is collected

35. Treatment

36. The primary concern when selecting antibiotics for community acquired
pneumonia is ensuring coverage of Streptococcus pneumoniae and
atypical organisms including Mycoplasma, Chlamydophila, and
Legionella. Treatment should always be individualized, but published
recommendations by the IDSA and ATS have suggested the following:

37. Empirical Antimicrobial Therapy for CAP
Patient Setting Empirical Therapy
Outpatients
Previously healthy and no use of
antimicrobials within the
previous 3 months
o Macrolide (strong
recommendation; level I evidence)
o Doxycyline (weak
recommendation; level III
evidence)ycycline
Presence of comorbidities such as
chronic heart, lung, liver
or renal disease; diabetes mellitus;
alcoholism; malignancies;
asplenia; immunosuppressing
conditions.
o A respiratory fluoroquinolone
(moxifloxacin, gemifloxacin, or
levofloxacin [750 mg]) (strong
recommendation; level I
evidence)
o A b-lactam plus a macrolide
(strong recommendation; level
Ievidence)

38. Empirical Antimicrobial Therapy for CAP
Patient Setting Empirical Therapy
(non ICU)Inpatients
o A respiratory fluoroquinolone
(strong recommendation; level I
evidence)
o A b-lactam plus a macrolide (strong
recommendation; level I
evidence)
(ICU)Inpatients o A b-lactam (e.g cefotaxime, ceftriaxone, or
ampicillin-sulbactam)
plus either azithromycin (level II evidence) or
a respiratory
fluoroquinolone (level I evidence) (strong
recommendation)
(for penicillin-allergic patients, a respiratory fluoroquinolone
and aztreonam are recommended)

39. Special concerns
If Pseudomonas is a consideration
 Antipseudomonal b-lactam (piperacillin tazobactam,
cefepime, imipenem, or meropenem) plus
fluoroquinolones (ciprofloxacin ,levofloxacin (750 mg),
gatifloxacin, moxifloxacin, gemifloxacin)
or
The above b-lactam plus an aminoglycoside and azithromycin
or
The above b-lactam plus an aminoglycoside and an
antipneumococcal fluoroquinolone
(for penicillin-allergic patients,substitute aztreonam for above b-lactam)
(moderate recommendation; level III evidence)

40. Special concerns
If CA-MRSA is a
consideration
add vancomycin or linezolid
(moderate recommendation;
level III evidence)
CA-MRSA, community-acquired methicillin-resistant Staphylococcus
aureus;

41. How Long to Treat Pneumonia?
If a patient is not immunosuppressed,
community-acquired pneumonia should be
treated with antibiotics for 5 to 7 Days
(Even in ICU)according to the IDSA and
ATS. Their advice applies even to severely
ill patients being treated for pneumonia in
the ICU.

42. Who Should Get Broad-
Spectrum Antibiotics for
Pneumonia?

43. Those patients with pneumonia and certain risk factors :
1. hospitalized or receiving antibiotics within 90 days,
2. nursing home residence, hemodialysis, home wound care,
3. immunosuppression,
4. a family member with a multidrug resistant organism, poor
functional status

44. Those patients are more likely to have
pneumonia due to drug-resistant bacteria.
They may fail standard therapy for
community acquired pneumonia, and have
been termed as having healthcare
associated pneumonia (HCAP).

45. Until recently, many experts have advised that
 Most such HCAP patients be treated with two anti-
Pseudomonas agents and coverage for MRSA.
However the concept of HCAP, and the implication that
all such patients should initially be treated with broad
spectrum antibiotics, are considered controversial
today, because the scheme leads to overuse of broad
agents.
 The risk justifies MRSA coverage, but not dual
coverage for Pseudomonas

46. Whom Should Be Admitted for
Pneumonia Treatment?
 Patients with a CURB-65 score ≥3 should be
hospitalized. CURB-65 has not been as well validated
as PSI, and notably does not include oxygen
saturation. As with all scoring systems, PSI and CURB-
65 provide guidance but are not absolute; admission
decisions may also include factors like lack of social
support, debility, degree of hypoxemia and its
chronicity, or nausea.

47. Where to Treat Pneumonia: Medical Ward
or ICU?
 The decision of whether to admit a patient
with community acquired pneumonia to
the ICU might have a major impact on
outcomes.
 Patients initially admitted to the medical
floor, then transferred to the ICU within 48
hours have had greater mortality than
those with more severe disease (intubated
or on pressors) admitted directly to the ICU
on admission.

48. The IDSA and ATS have suggested that any patient with 3 of the
following 9 criteria be considered for ICU admission:
1. confusion,
2. BUN ≥20 mg/dL,
3. respiratory rate ≥ 30/min,
4. multilobar pneumonia,
5. hypoxemia with PaO2/FiO2 < 250,
6. platelets < 100,000 mm³,
7. hypotension (SBP<90 mm Hg),
8. hypothermia < 36º C, or
9. white blood cell count < 4,000/mm³.

49. The use of systemic corticosteroids in
patients with CAP?
 May reduce the length of time until clinical
stability, reduce hospital length of stay,
reduce the need for mechanical ventilation,
and reduce the incidence of adult
respiratory distress syndrome (ARDS).
 Recent clinical trials have also shown a
possible overall reduction in mortality,
although these later results remain in
doubt.

50. The use of systemic corticosteroids in
patients with CAP?
 However ,there is insufficient data or
agreement on the dose or duration of
the steroid therapy.
 There are current ongoing double-blind,
randomized, controlled clinical trials to
examine the short- and long-term
effects of corticosteroid use in the
management of CAP.

51. The use of systemic corticosteroids in
patients with CAP
 may reduce the length of time until
clinical stability, reduce hospital length
of stay, reduce the need for mechanical
ventilation, and reduce the incidence of
adult respiratory distress syndrome
(ARDS). [49, 50] Recent clinical trials
have also shown a possible overall
reduction in mortality, although these
later results remain in doubt. [51, 52]
Furthermore,