Chapter 6

Question 1

What is the pathogenesis of aspiration pneumonia?

Answer 1

1. Due to unconsciousness or impaired swallowing
2. Mixed organisms + Gastric Acid + Food = Infective Pneumonia + Chemical Damage
   - organisms are usually mixed but often contain anaerobes and oropharyngeal bacteria
3. Frequently leads to lung abscess

Question 2

What organisms cause atypical pneumonia?

Answer 2

1. Mycoplasma
2. Chlamydia
3. Rickettsia

Question 3

What is the presentation of atypical pneumonia?

Answer 3

1. Minimal Airspace Exudate
2. Marked infiltration of alveolar septa/interstitium by chronic inflammatory cells (pneumonitis)
3. Symptoms of pneumonia but absence of consolidation on X-Ray

Question 4

What is the presentation of viral pneumonia?

Answer 4

Interstitial inflammatory response dominated by lymphoid cells

Question 5

What condition does severe viral pneumonia lead to?

Answer 5

Acute Respiratory Distress Syndrome

Question 6

Is viral pneumonia common?

Answer 6

No. Rarely cause symptomatic pneumonia; more commonly causes upper respiratory tract infection

Question 7

What viruses cause viral pneumonia?

Answer 7

1. Influenza (H5N1 strain, conventional strains can develop secondary bacterial pneumonia following viral damage to the airway epithelium)
2. SARS-COv-1
3. SARS-COv-2 (few)

Question 8

What two settings cause infection by organisms of low pathogenicity?

Answer 8

1. Immunocompromised patients
2. Pt with previous damage to lung resulting in stagnant secretions (ie chronic bronchitis, bronchiectasis, cavitation due to previous TB)

*ascertain if organisms are colonising or causing disease (symptomatic? progressive tissue damage?)

Question 9

What organism causes fungal ball

Answer 9

Aspergillus

Question 10

How to tell if there has been previous infection in someone’s lung?

Answer 10

Minimal surrounding active infection

Question 11

What organism causes opportunistic infection in HIV pt?

Answer 11

Pneumocystis jirovecii

Question 12

Are HIV pts at risk of cancer? If so, what?

Answer 12

Yes. Lung, Kaposi, Non Hodgkin

Question 13

What is the pathogenesis of bronchiectasis?

Answer 13

1. Two main factors - interference with drainage of secretions (due to obstruction of proximal airway, abnormality in mucus viscosity [cystic fibrosis], immotile cilia syndrome) OR recurrent and persistent infection
2. Combination of obstruction and infection leads to persisstent inflammation and damage & dilation to bronchial walls

Question 14

How might patient with bronchiectaiss present?

Answer 14

1. recurrent infection
2. hemoptysis

Question 15

How does the lung look like in bronchectasis?

Answer 15

permanent abnormal dilation of the main bronchi
airways contain purulent secretions, chronic inflammation of wall with loss of normal epithelium

Question 16

What are 3 complications of bronchiectasis?

Answer 16

1. Chronic suppuration with lung abscess
2. Hematogenous spread of infection
3. Secondary Amyloidosis

Question 17

What is a lung abcess?

Answer 17

Localised area of suppurative necrosis, usually forming large cavities

Question 18

Why is lung abscess more common in infections?

Answer 18

1. Pulmonary Infarction
2. Aspiration
3. Bronchial Obstruction
4. Bronchiectasis
5. S. aureus or any other pyogenic bacteria

Question 19

Can there be multiple abscesses?

Answer 19

Yes. Septic emboli

Question 20

What are complications of lung abscess?

Answer 20

1. Rupture into pleura causing empyema and pneumothorax
2. Hemorrhage from erosion into a pulmonary vessel
3. bacteraemia