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Flashcards in Pneumonia Deck (68)
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1

Why is pneumonia important

- common disease with high rates of hospitalisation
- it kills
- expensive to treat
- treatable

Presents to all specialities
- GP
- A and E
- acute/general medicine
- respiratory medicine
- ITU
- surgeons
- Oncology
- HIV
- Radiology
- Paediatrics
- care the elderly

2

describe the epidemiology of pneumonia

• Incidence 5-11 cases/1000 adults
– 5-12% of respiratory infections presenting to GP’s
• Highest incidence in very young and very old
– BTS Audit – Mean age 71 (16-105) – 25% ≥85
• 22-42% require hospital admission in UK
• 5-7% need intensive care = 5% of ITU admissions – 50% Mortality
• 18.3% 30 day mortality
– 20% in first 24 hours – Median 5 days
• HAP affects 0.5-1% of inpatients

3

What is pneumonia

Symptoms and signs consistent with an acute lower respiratory tract infection associated with new radiographic shadowing for which there is no other explanation

4

What are the symptoms of pneumonia

Localised
- Cough and at least one other from:
- pleural pain
- dyspnoea
- tachypnoea

Systemic
- sweating, fevers, shivers, aches and pains and/or
- fever greater than 38 degrees

5

What are the signs of pneumonia

- new and focal chest signs
- new radiographic shadowing with no other explanation

6

How can you classify pneumonia

- aetiology
- patient factors
- clinical features

7

how do you classify pneumonia according to the aetiology

Organism

Source of infection
- community acquired
- health care associated - hospital acquired, ventilator associated, nursing home

8

How do you classify pneumonia according to patient factors

- underlying disease
- immunocompromise states

9

how do you classify pneumonia according to clinical features

- severity
- symptoms and signs

10

What organisms causes the most pneumonia

Strep Pneumoniae - greater than 50% of all cases

11

in approximately 50% of pneumonia cases there is...

no pathogen identified

12

what other factors can be used to help predict the organism that is causing the pneumonia

- Source of infection
- patient factors
- clinical features

13

How do you define hospital acquired pneumonia

- defined as someone who has developed pneumonia who has been in hospital for more than 48 hours or 10 days post discharge

14

What pathogens can cause hospital acquired pneumonia

Increased risk of
- aspiration
- H.influenzae
- Gram negative
- Staph aureus

15

What patient factors can help predict the most likely pathogen causing pneumonia

- Elderly are less likely to have M.pneumoniae and Legionella
- Diabetes - increase in bacteraemic pneumococcal pneumonia
- COPD - increase in H.influenzae and M. Catarrhalis
- Alcoholism - more likely to have all organisms - consider aspiration as more likely to aspirate and more likely to be infected with anaerobic bacteria
- Immunodeficiency - still the most common cause but more likely to be due to legionella, neutropenic sepsis and TB, PCP etc

16

clinical features cannot ...

predict the likely pathogen

17

what pathogens do you need to cover in hospital acquired pneumonia

- Most commonly gram negative enterobacteria or staph Aureus
- pseudomonas
- Klebsiella
- bactericides
- clostridia
– Cover Gram Negatives
– No need to cover Legionella

18

what are the lung defence mechanisms

designed to treat a decrease in particle size as you go down the respiratory tract
- filtration/deposition in upper airways
- cough reflex
- mucociliary clearance
- alveolar macrophages
- humeral and cellular immunity
- oxidative metabolism of neutrophils

19

what can cause defects in the airway host defences

- filtration/deposition in upper airways = anatomical abnormalities
- cough reflex = aspiration e.g. post stroke
- mucociliary clearance = cystic fibrosis, bronchiectasis
- alveolar macrophages = alcoholism
- humeral and cellular immunity = HIV
- oxidative metabolism of neutrophils = chemotherapy

20

What has to happen in order for pneumonia to infect the body

Immune defence
- defect in host defence
- virulent organism
- overwhelming inoculum such as aspiration

21

What investigations are needed in pneumonia
- aid and confirm diagnosis
- stratify severity/risk
- target therapy

Aid/confirm diagnosis
- chest radiograph - within 4 hours
- FBC (WCC usually >15x109/l)/CRP (usually >100mg/l)

Stratify severity/Risk
- urea and electrolytes
- FBC/CRP/(LFT)
- Oxygen saturations
- ABG

Target therapy
- blood and sputum cultures – Pneumococcal urinary antigen
– Legionella urinary antigen +sputum culture
– Mycoplasma PCR (Sputum/Throat swab)
– Chlamydophilia PCR/Complement fixation
– Viral PCR(Nose/Throat swab)

22

What is the aim of microbiology

– Identify Pathogenic Bacteria
• Microscopy

– Test Sensitivity to Antibiotics
• Culture and Sensitivities

23

what cultures can be used to assess the microbiology of the pneumonia

- Blood and/or Sputum Cultures
- urinary antigens - only for pneumococcus and legionella
- PCR - nose or throat swab for viruses

24

what is urinary antigen test supposed to be for

- Pneumococcoal
- legionella – Only tests for Serogroup 1 (90% of European cases)

25

Describe urinary antigen tests

– Highly Sensitive (>80%) and Specific (>95%) – Rapid Result
– Remain Positive on Treatment
– No information on Antibiotic Sensitivities
– If positive → Specific sputum culture

26

When does staph aureus usually cause pneumonia

- winter
- 39% influenza symptoms
- 39% influenza virus - 50% of those admitted to ITU

27

What radiographic changes might you see in pneumonia

- Consolidation
- air bronchograms - highly suggestive on pneumonia
- shadowing
- collapse
- pleural effusion
- lymphadenopathy

28

What are air bronchograms

- dark lines going through a white area of lung
- air bronchi surrounded by the pus in the alveoli

29

How long does it take for pneumonia changes on a radiograph

- 73% at 6 weeks, slower in the elderly or multi lobar

30

When would you use CT scanning in pneumonia

- diagnostic doubt
- underlying cause such as cancer