Respiratory Infections Flashcards Preview

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Flashcards in Respiratory Infections Deck (53):
1

Location of Respiratory Infections

Trachea, Bronchi, Bronchioles, Alveoli

2

Barriers to infection

Nasal hair, Mucosillary cells, Coughing, Normal flora, Phagocytic inflammatory cells

3

Normal flora

- changes with time (due to hospitalization)
- alpha hemolytic colonies in pharyngeal culture

4

Pathogens

- alpha hemolytic colonies in sputum or bronchial aspirate

5

Differentiating infection

- look at method and site of infection
- presence of white blood cells
- number of organisms present
- clinical syndrome present
- some pathogens are always present (M.TB)

6

Respiratory Infections (Risk Factors)

- Imunnologic status
- Age (elderly, young at higher risk)
- Reduced clearance promotes infection
- Airway obstruction (H. flu epiglottitis)
- Seasonal patterns contribute (M. pneumo has none)

7

Empirical treatment

- antibiotics should be given before ID for ICPs
- infections with hard-to-reach specimens
- infections with known/recurring pathogens

8

Virulence factors

- adherence, fimbrae (Enterics, Streps)
- toxin elaboration (C. diphtheriae, Pseudomonas, pertussis)

9

Evasion of host defense

- capsules for preventing phagocytosis (S. pneumo, H. flu, Pseudomonas, Klebsiella)
- intracellular (TB, Chlamydia)
- Proteases (cleave antibodies)

10

Upper Respiratory Tract Infections

Pharyngitis, Sinusitis, Otitis media, Epiglottitis, Pertussis

11

Pharyngitis

- commonly Group A strep in kids or viral (with rhinorrhea)
- symptoms of Group A strep
- culture or rapid antigen testing
- person-to-person transmission
- pain, difficulty swallowing, fever with bacterial
- C. diphtheriae: pharyngeal membrane

12

URT Infections (pathogenesis)

inflammatory effects of bacteria

13

URT complications

sinusitis, otitis media, pneumonia

14

URT lab diagnosis

- primary: differentiate between viral and bacterial
- secondary: detect uncommon bacterial causes

15

URT culture

- streak SBA
- Latex agglutination
- Rapid antigen test
- treat with penicillins and cephalosporins

16

Sinusitis (causes)

- commonly viruses (rhinovirus, influenza)
- 2% are bacteria (S. pneumo, H. flu, S. pyogenes, M. catarrhalis, S. aureus)
- fungal is uncommon

17

Sinusitis (pathogenesis)

- swelling and blockage of sinuses
- pain and possible complications
- complications: orbital cellulitis, osteomyelitis, meningitis

18

Sinusitits (lab diagnosis)

- direct sinus puncture or aspiration
- culture on SBA, MAC, Chocolate
- empirical information

19

Otitis media

- most common in preschool aged kids
- fever, irritability, ear pain, drainage, red tympanic membrane

20

Otitis media (pathogenesis)

- due to anatomic immaturity
- causes damage to tympanic membrane

21

Otitis media (lab diagnosis)

- empirical
- antibiotic treatment in kids < 2 y/o

22

Epiglottitis

- caused by Hib
- preschool-aged kids

23

Epiglottitis (pathogenesis)

- severe pharyngitis, sore throat, severe pain on swallowing
- edema in soft tissues
- sudden onset of airway obstruction
- requires hospitalization and IV fluids

24

Epiglottits (lab diagnosis)

- direct swab culture and blood cultures
- direct smear (WBC's, pleomorphic GNR's = H. flu)
- culture on chocolate

25

Pertussis

- caused by Bordetella
- highly transmissible in ICPs, babies
- vaccine available

26

Pertussis (pathogenesis)

pertussis toxin

27

Pertussis (lab diagnosis)

- nasopharyngeal swab using Dacron/Calcium alginate
- plate on Bordet-Gengou
- serology: DFA testing, PCR testing

28

Lower Respiratory Tract Infections

- Bronchitis, Bronchiolitis, Influenza, SARS, Pneumonia, Empyema, TB
- caused by inhalation of aerosols, aspiration of oral/gastric contents, or hematogenous spread

29

Bronchitis and Bronchiolitis

- follows epidemics of influenza, RSV, and other viruses
- more frequent in winter months

30

Bronchitis and Bronchiolitis (pathogenesis)

- infection and damage to the airway
- inflammatory response, necrotic debris, edema
- begins as URT infection
- acute is infectious form
- chronic requires 3 months of symptoms for 2 years

31

Bronchitis and Bronchiolitis (lab diagnosis)

- similar procedure as pharyngitis
- secondary infection easily obtained from sputum
- hospitalized patients tested for RSV for infection control

32

Influenza

- late fall, early winter
- Influenza A and B

33

Influenza (pathogenesis)

- antigenic shift (production of new virus)
- fever, myalgia, fatigue

34

Influenza (diagnosis)

- detection of virus, viral antigen, or viral nucleic acid
- treat with neuraminidase inhibitors or vaccine

35

Severe Acute Respiratory Syndrome (SARS)

- fever without cough
- dyspnea
- progressive respiratory failure

36

LRT (Viral causes)

Adenovirus, Metapneumovirus, Bocavirus

37

Community-acquired pneumonia

- most affected are elderly or have underlying disease
- kids/elderly: RSV, parainfluenza
- adults: S. pneumo, Hib, M. pneumo
- atypical: M. pneumo, Legionella pneumophila

38

C-A pneumonia (pathogenesis)

- fever, lung infiltrates
- cough with blood-tinged sputum, left shift WBC count

39

C-A pneumonia (lab diagnosis)

- therapy is empirical
- blood cultures and sputum on hospitalized patients
- PCR and other molecular tests
- antigen tests
- direct examination of sputum

40

Direct examination of sputum

Acceptable: < 10 epithelial cells, > 25 PMN's

41

Expectorated sputum

- no WBCs
- heavy epithelial and bacteria
- saliva, not sputum

42

Aspirated sputum

- no WBCs or organisms
- specialized cells from bronchial tree and mucus

43

Health Care-Associated Pneumonia (HCAP)

- hospitalized or in a nursing home facility
- can also be ventilator associated pneumonia (VAP)
- greater risk of multi-drug resistant pathogens
- Pseudomonas, Kleb. pneumo, Acinetobacter, MRSA

44

HCAP (pathogenesis)

- patients own respiratory flora, GI tract or hospital flora
- due to aspiration of flora
- intubation of lower airway pushes flora deeper
- nasogastric intubation
- fever, altered WBC count, purulent sputum

45

HCAP (lab diagnosis)

- same as community-associated
- expectorated sputum specimen
- SBA, Chocolate and MAC
- anaerobic cultures if no contamination

46

Empyema

- collection of purulent fluid in pleural cavity
- S. aureus, S. pneumo, S. pyogenes

47

Empyema (pathogenesis)

- fever, chills, night sweats
- complicates chest surgery
- limits motion and function of lungs
- resistant to antimicrobials

48

Empyema (lab diagnosis)

aspirate of pleural fluid (thoracentesis)

49

Tuberculosis

- Mycobacteria in ICP's
- NTM's (Mac, M. kansasii, M. chelonae)
- Opportunistic fungal pathogens

50

Tuberculosis (lab diagnosis)

- acid-fast stain
- skin test
- serology, nucleic acid tests

51

Aspiration pneumonia

- gastric or oropharyngeal are inhaled into LRT
- C-A: S. pneumo, H. flu, Staph, Enterics
- HACP: Gram-negatives like Pseudomonas
- use broad spectrum antibiotics

52

Respiratory Infections in ICPs

- Pneumocystis
- Bacterial pneumonia and tuberculosis
- Cryptococcus
- Lab: sputum and blood culture, acid-fast, fungal tests

53

Bioterrorism respiratory infections

B. anthracis (anthrax attack in 2001)