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MODHIII - Unit 3 > Pneumonia > Flashcards

Flashcards in Pneumonia Deck (45)
1

How does pneumonia rank on the cause of death for world and US

- 3rd most common cause of death in the world
- 6th leading cause of death in US: 50,000 in 2010

2

Number of cases of community acquired pneumonia (CAP) per year

5 million

3

Outpatient vs. Inpatient pneumonia stats

- 80% treated as outpatients & 20% as inpatients
- mortality rate among outpatients

4

Types of pneumonia

- community acquired pneumonia (CAP)
- hospital acquired pneumonia (HAP)
- healthcare associated

5

Mechanisms of lung to defend against pathogens

- nasal vibrissae and turbinates capture large inhaled particles
- gag reflex and cough protect from aspiration
- branching of tracheobronchial tree traps microbes in airway
- mucociliary escalator sweep entrapped contents up to oropharynx

6

Role of normal flora that is typically adherent to mucosal cells of oropharynx

- prevent pathogenic bacteria from binding & decreases risk of pneumonia caused by more virulent bacteria

7

What occurs when barriers are overcome

- alveolar macrophages phagocytize and destroy pathogens
- if not killed, pathogens are eliminated via mucociliary elevator or lymphatics
- macrophages release cytokines & chemokines (TNF, IL-8) and leukotriene B4, which recruit neutrophils from blood stream to alveolar spaces, where they uptake and degrade microorganisms
- specific IgG bind surface of organisms and augment the ability of neutrophils and macrophages to phagocytize the bacteria

8

How can pathogens reach the lungs

- microaspiration of oropharyngeal contents
- inhalation of small aerosolized droplets that contain microorganisms
- consequence of a bloodstream infection/hematogenous spread
- direct spread from adjacent structures

9

Most common route to acquire pneumonia

- microaspiration of oropharyngeal contents

10

Microorganisms associated with microaspiration of oropharyngeal contents

- strep pneumonia, haemophilus influenzae

11

Microorganisms associated with inhalation of small aerosolized droplets

- mycobacterium tuberculosis, and viral infections

12

How do patients typically present

- fever, cough, sputum, leukocytosis, radiographic infiltrate, crackles, hypoxemia, hemoptysis, respiratory alkalosis, dyspnea

13

What causes fever in pneumonia

- IL-1 & TNF

14

What causes leukocytosis and increased purulent secretions

- chemokines (IL-8, GCSF) stimulate release and migration of neutrophils to the lung

15

What causes radiographic infiltrate, crackles, and hypoxemia

- inflammatory mediators create alveolar capillary leak

16

What causes respiratory alkalosis

- increased respiratory drive in the inflammatory response syndrome

17

What causes dyspnea

- decreased compliance due to capillary leak, hypoxemia, increased respiratory drive, increased secretions, and infection related bronchospasm

18

What does pneumonia patient become hypoxemic

- alveoli become filled with purulent secretions, which leads to shunts

19

Steps to diagnosing pneumonia

1. evidence of infection: fever, chills, leukocytosis
2. signs/symptoms localized to the respiratory system: cough, increased sputum, SOB, angina, abnormal pulmonary exam
3. new infiltrate on chest radiograph

20

Organisms associated with typical pneumonia presentation

- S. pneumonia, haemophilus influenzae, S. aureus

21

Organisms associate with atypical pneumonia presentation

- mycoplasma pneuminae, chlamydia pneumoniae, legionella

22

Organisms associated with travel to central US

histoplasma capsulatum

23

Physical exam findings with pneumonia patient

- use of accessory muscles of respiration
- increased tactile fremitus with dull percussion reflecting consolidation
- crackles, bronchial breath sounds, pleural friction rub

24

Physical exam sensitivity and specificity

- sensitivity: 58%
- specificity: 67%

25

What is needed to diagnose pneumonia

Chest Radiograph

26

Purpose of chest radiograph

- establish diagnosis of pneumonia
- differentiates pneumonia from other conditions
- assesses extent of involvement of lungs
- occasionally suggest an etiologic diagnosis

27

Possible microbiologic work ups for pneumonia

- sputum gram stain and culture
- blood culture
- urinary antigen tests
- PCR
- Serology

28

Sputum gram stain and culture: adequacy

- to be adequate: >25 neutrophils,

29

Limitations of sputum gram stain and culture

- 30% of patients have non productive cough
- only 14% can provide an adequate sample
- 15-30% already received antibiotics

30

Blood culture: CAP stats

- 5-14% of blood cultures from patients hospitalized with CAP are positive

31

Blood culture: hematogenous staph aureus pneumonia stats

- nearly always positive blood culture
- positive in only about 25% of cases in which inhalation or aspiration is responsible for the CAP

32

How often can specific microbiologic cause be established

50%

33

How antibiotic treatment is chosen

- pathogen is identified
- empiric treatment

34

Factors that effect antibiotic chosen for treatment

- comorbidities, immunosuppression
- risk factors for multidrug resistant pathogens (MDR): hospital workers
- resistance patterns
- environmental exposures

35

Importance of timing of treatment

- interval of more than 4 hours b/w initial presentation and first antibiotic dose is associated with increased in hospital mortality

36

Treatment for patients stable enough to be treated as outpatients

- treated empirically
- cause of infection not sought b/c of substantial cost of testing
- choose antibiotic which covers most common organisms

37

Treatment for patients being admitted to the hospital

- guidelines recommend empirical therapy with broader spectrum antibiotics
- test for microbial diagnosis

38

What if influenza is active in the community

- antiviral treatment is recommended as soon as possible for all patients with suspected or confirmed infection

39

Pneumonia prevention

- pneumococcal vaccination
- influenza vaccination
- smoking cessation

40

Pneumococcal vaccine

1. pneumovax
2. prevnar

41

Pneumovax

- 23 valent polysachharide
- covers 88% of strains causing bacteremia/meningitis
- indicated for elderly or patients with chronic health conditions

42

Prevnar

- 13 different strains
- indicated for elderly

43

Influenza vaccination

- 20,000 deaths annually
- prevention is most effective management strategy
- everyone 6 months of age and older should get vaccine every season

44

Importance of pneumococcal vaccine

- key to prevent INVASIVE pneumococcal disease

45

What is the most common infectious cause of death in the world

pneumonia