1. Community Acquired Pneumonia
Prof. Dr. Çağrı BÜKE
Yeditepe University Medical Faculty
Infectious Diseases and Clinical Microbiology

2. CAP Ç. BÜKE Community-acquired pneumonia is responsible for great
Mortality
Morbidity
High costs
Suspected CAP is defined by acute symptoms and presence of signs of lower respiratory tract infection (LRTI) without other obvious cause
For Definitive diagnosis of CAP new pulmonary infiltrate on chest radiograph is needed

3. Signs and Symptoms for CAP
Ç. BÜKE
Signs and Symptoms for CAP
Dyspnoea
Cough
Fever
New focal chest signs
In elderly people, clinical presentation can have less evident;
An altered state of consciousness, gastrointestinal discomfort, and fever can be absent
Diagnosis is frequently delayed

4. Signs and symptoms for CAP
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Signs and symptoms for CAP
For some pathogens, unusual clinical presentations can be seen;
Pneumonia due to Legionella spp.; can present with headache, confusion, diarrhoea, and clinical manifestations of hyponatraemia
Pneumonia due to Mycoplasma pneumoniae; can be associated with upper respiratory involvement (otitis, pharyngitis), skin changes (Stevens-Johnson-like syndrome), and haemolytic anaemia.

5. Differential diagnosis of CAP
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Differential diagnosis of CAP
Many diseases and syndromes have clinical signs and symptoms that can mimic pneumonia
Delays in correct diagnoses of CAP increase the risks of poor outcomes
In patients with not-severe CAP, the main differential diagnosis is upper respiratory tract infection
In these cases, clinicians should rely on; 1) clinical evaluations (including manifestations of LRTI, 2) focal chest sounds, exclusion of other possible diagnosis) and 3) point-of-care tests (eg, C-reactive protein [CRP])

6. Differential diagnosis of CAP
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Differential diagnosis of CAP
Patients with severe CAP; should be monitored for other life-threatening disorders
Differentiation of pneumonia from non-infectious disorders such as acute heart failure is occasionally difficult
Prompt start of antibiotic treatment is recommended
Biomarkers (eg, procalcitonin [PCT]) can help;
In the early differentiation from heart failure
Avoiding antibiotic misuse

7. Recurrent pneumonia Ç. BÜKE
In patients with recurrent pneumonia, underlying diseases should be suspected such as;
Lung cancer
Metastasis
Tuberculosis
Foreign bodies
Hypersensitivity pneumonitis
Unknown immunosuppressed status

8. Epidemiology Ç. BÜKE Worldwide incidence 0.5-1.1% annually in Europe
The rate is increasing with age
6/1000 patients years
20/1000 patientrs years
34/1000 patients over 75 years
Incidence in Turkey
The patients admitted to primary health care institutions with pneumonia symptoms is 2.8% /year
Cause of hospitalisation due to CAP is 1.9% /year

9. Ç. BÜKE
Epidemiology
Short-term mortality (in-hospital and 30 day mortality) for
Hospitalised patients ranges from 4·0% to 18·0%
Patients in intensive care, this rate can reach 50%
Costs related to CAP are high
Only few approaches (such as reducing the length-of-stay, adequate use of antibiotics, and the introduction of vaccines) have reduced these costs so far

10. Causative pathogens Ç. BÜKE
Streptococcus pneumoniae is the main pathogen that causes CAP worldwide, independent of age
In Europe, nearly 35% of cases, worldwide it is about 27.3%
The introduction of the conjugated pneumococcal vaccine in children has decreased the incidence of the invasive penicillin-R cases; but infections with serotypes not affected by the vaccine have increased
About 90 distinct pneumococcal serotypes have been identified throughout the world

11. Causative pathogens Ç. BÜKE
The polysaccharide vaccine consists of purified capsular polysaccharides from the 23 serotypes causing about 90% of invasive pneumococcal infection in industrialized countries.
Pneumococcal conjugate vaccines contain polysaccharides from 13 serotypes covering 65–80% of serotypes associated with invasive pneumococcal disease among young children in western industrialized countries.

12. Causative pathogens Ç. BÜKE
Other frequent causes include Haemophilus influenzae, which accounts for 12% (2·4–44·9%) of cases
Atypical bacteria (including Mycoplasma, Chlamydia, and Legionella spp), which caused 22% of cases
In adults, viruses, particularly influenza, rhinovirus, and coronaviruses, cause a third of cases of pneumonia

13. Pathophysiology Ç. BÜKE
In healthy individuals, many microorganisms colonise the nasopharynx and oropharynx
Microaspiration of contaminated secretions can cause infections in the lower airways
The glottal reflexes, the presence of complement proteins and immunoglobulins, the secretion of peptides with antimicrobial activities, and the inhibition of bacteria binding all protect the lower airways
The healthy microbiota of the upper airway also exert protection effects

14. Pathophysiology Ç. BÜKE
In healthy individuals, many microorganisms colonise the nasopharynx and oropharynx
The use of broad-spectrum antibiotics can modify the microbiota and predispose to infection
The interactions between the virulence of the pathogens, the amount of inoculum, and the innate and adaptive immune responses determine the development of pneumonia

15. Ç. BÜKE
Risk factors
All individuals are at risk for development of pneumonia
However, some individuals are more prone to pneumonia than are others due to intrinsic and extrinsic factors
New findings have revealed individual genetic variability in the predisposition to the development of pneumonia and its clinical presentation
Specific variants of the FER gene are associated with a reduced risk of death in patients with sepsis due to pneumonia
TLR6 polymorphism is associated with increased risk of Legionnaires’ disease

16. Diagnosis of pneumonia
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Diagnosis of pneumonia
Laboratory evaluation
In patients who clinicians suspect to have community- acquired pneumonia, blood tests can provide information about the inflammatory state
Leucocyte cell number and characteristics [neutrophilia]
CRP
Biomarkers can support clinicians in the differentiation of bacterial pneumonia from other disorders
Antibiotic is encouraged PCT concentrations; higher than 0·25 μg/L; and is strongly encouraged, PCT concentrations higher than 0·5 μg/L

17. Diagnosis of pneumonia
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Diagnosis of pneumonia
Microbiological evaluation
Microbiological evaluations are recommended for higher-risk patients such as those with;
Severe CAP,
Special disorders (eg, asplenia, immunosuppression, HIV infection, and alcohol abuse)
Septic shock
A risk of resistant pathogens
Failure of the initial empirical treatment

18. Diagnosis of pneumonia
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Diagnosis of pneumonia
Microbiological evaluation
Although a positive blood (or pleural fluid) culture test definitively identifies the pathogen responsible for pneumonia,
A positive respiratory tract sample needs clinical interpretation because the microorganism can be present due to colonisation or be part of the healthy flora
The collection of any sample after the administration of antibiotics increases the rate of false-negative results.

19. Diagnosis of pneumonia
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Diagnosis of pneumonia
Urinary antigens
Urinary antigens are useful for the detection of all serotypes of S pneumoniae and
For serogroup 1 of Legionella pneumophila (responsible for about 90% of legionella cases of CAP).
Advantages of these tests are promptness (<15 min), reasonable accuracy, and the ability to detect the infection while the patient is receiving antibiotic therapy
The urinary antigens have a sensitivity of 75% and a specificity of 97%

20. Diagnosis of pneumonia
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Diagnosis of pneumonia
Blood serology test
Available for Chlamydia pneumoniae, M pneumoniae, and Legionella spp; however, their clinical usefulness is limited by the delay in the results and difficulty in interpretation
PCR
Available for bacterial causes related to Mycoplasma, Chlamydia, Streptococcus, and Legionella spp, which have to be done on bronchoalveolar lavage fluid or nasopharyngeal swabs
PCR tests are available for several respiratory viruses

21. Diagnosis of pneumonia
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Diagnosis of pneumonia
Imaging
Thoracic images are essential for several aspects of pneumonia management
Chest radiograph has diagnostic accuracies of 75% for alveolar consolidation and 47% for pleural effusion
CT is considering as the gold standard technique
But CT has limitations that include increased cost, radiation exposure, and the impossibility of doing CT at the bedside
Lung ultrasound is a useful method for pneumonia with a sensitivity of 94·0% (95% CI 92·0–96·0) and a specificity of 96·0% in adults

22. Management of pneumonia
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Management of pneumonia
Two questions need to be answered;
Does the patient need to be admitted in the hospital and
Should they be treated in intensive care
Scores and biomarkers can assist the clinical judgment
The Pneumonia Severity Index (PSI) and CURB-65 are the most frequently used scores
Patients should be admitted to intensive care; when they require mechanical ventilation, vasopressors and have thrombocytopenia, hypothermia, and leucopenia

23. Ç. BÜKE
- Confusion
- Urea
- Respiratory rate
- Blood pressure
- Age

24. Pneumonia severity index for CAP
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Pneumonia severity index for CAP

25. Selection of antibiotics
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Selection of antibiotics

26. Selection of antibiotics
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Selection of antibiotics

27. Selection of antibiotics
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Selection of antibiotics

28. Timing of antibiotic treatment
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Timing of antibiotic treatment
The first dose of antibiotics should be given as soon as possible after diagnosis of CAP
The antibiotics should be started preferably within the first 4–8 h of hospital arrival
In unstable patients with severe sepsis or septic shock, the time to the first dose is strongly associated with a reduction in mortality, and administration in the first hour after diagnosis is recommended

29. Respiratory support Ç. BÜKE
Patients with acute respiratory failure due to pneumonia must be assessed early for a need for respiratory support and oxygen saturation is an important marker for outcome
Patients with severe pneumonia are candidates for invasive mechanical ventilation, and a delay can lead to an increased mortality
Patients with moderately severe disease can be cautiously managed with the use of non-invasive ventilation by trained staff

30. Antibiotic policy Ç. BÜKE
When microbiological tests become available, it is important to re-evaluate antibiotic treatment
Antibiotics should be adapted according to antibiogram results
Narrowed according to the identified pathogen, and discontinued when a diagnosis of pneumonia is unlikely
Most patients in hospital with CAP began treatment with an intravenous antibiotic
A switch to oral therapy should be considered for patients who reach clinical stability

31. Duration of antibiotic therapy
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Duration of antibiotic therapy
5 days of treatment should be given for low-severity pneumonia with clinical stability after 3 days of treatment
7 days should be given for severe pneumonia, which should be adapted depending on the improvements in symptoms and stability
Biomarkers can be used to guide antibiotic duration. One-time PCT values lower than 0·25 μg/mL or a decrease from the peak by 80–90% are a strong indication that antibiotics should be discontinued

32. Prevention and vaccines
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Prevention and vaccines
Influenza vaccines are robustly associated with a reduced rate of pneumonia and better outcomes
30% reduction in the rate of pneumonia and influenza infection in individuals older than 65 years old
Two vaccines are available for S pneumoniae: the pneumococcal polysaccharide vaccine and the pneumococcal conjugate vaccine

33. Prevention and vaccines
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Prevention and vaccines
By comparison with pneumococcal polysaccharide vaccine, the pneumococcal conjugate vaccine seems to induce a stronger and longer-lasting secondary immune response with booster effect
The US Centers for Disease Control and Prevention recommended the administration of both pneumococcal conjugate vaccine-13 and pneumococcal polysaccharide vaccine-23 in series to all adults aged 65 years and older

34. Ç. BÜKE