lecture 7/tutorial 9 - pneumonia

Question 1

What is pneumonia?

Answer 1

Inflammation of the lung parenchyma, usually caused by an infectious organism

Question 2

What are the 3 categories in which pneumonia is further classified?

Answer 2

1. By clinical setting (community acquired, etc.)
2. By organism (bacteria type)
3. By morphology (lobar vs broncho-)

Question 3

What are the 4 classifications of pneumonia in terms of clinical setting/mode of transmission?

Answer 3

Community-acquired, hospital acquired, immunocompromised, aspiration

Question 4

What are the predisposing factors for pulmonary infections?

Answer 4

cilia injury, decreased alveolar macrophages, oedema or congestion, retention of secretions

Question 5

What is the difference between the spread of consolidation in broncho- and lobar pneumonia?

Answer 5

Bronchopneumonia spreads down the bronchi and into the alveoli causing consolidation all the way down the airways. Lobar pneumonia has almost simultaneous consolidation of a whole lobe, but the airways are not the centre of inflammation.

Question 6

What anatomical feature allows for confluent consolidation in an entire lobe with lobar pneumonia?

Answer 6

Pores of Khon - allows spread between adjacent alveoli

Question 7

What bacteria most commonly causes Lobar Pneuomonia?

Answer 7

Streptococcus Pneumoniae, aka pneumococcus

Question 8

What is the pathogenesis of lobar pneumonia?

Answer 8

1. capillaries in lungs become congested and fluid seeps into the lungs due to increased pressure.
2. red cells enter the alveoli via diapedesis causing red hepatisation.
3. polymorphs enter alveoli and ingest opsonised bacteria
4. macrophages ingest dead inflammatory cells and pus and congestion subsides, resulting in grey hepatisation
5. exudate is digested and cells are phagocytosed resulting in resolution

Question 9

What are the findings of a chest xray of a patient with bronchopneumonia?

Answer 9

Patchy opacities across multiple lung lobes, mostly in the base due to gravity pooling congestion and oedema.

Question 10

What are the four defined stages of lobar pneumonia?

Answer 10

1. congestion
2. red hepatisation
3. grey hepatisation
4. resolution

Question 11

What type of pneumonia do viruses typically cause?

Answer 11

Atypical

Question 12

What is viral atypical pneumonia?

Answer 12

Inflammatory exudate in the alveolar walls, rather in the alveolar spaces like in typical pneumonia

Question 13

What is the key complication of viral pneumonia?

Answer 13

ARDS - acute respiratory distress syndrome

Question 14

What is acute respiratory distress syndrome?

Answer 14

When there is injury to pneumocytes and pulmonary endothelial cell activation the alveoli become coated with a hyaline membrane, impairing gas exchange

Question 15

What is the key histological feature of ARDS?

Answer 15

Hyaline membranes lining alveoli

Question 16

What bacteria commonly causes pneumonia in AIDS patients?

Answer 16

Pneumocystis jirovecii

Question 17

What type of pneumonia is caused by pneumocystis jirovecii?

Answer 17

Atypical - inflammatory exudate in alveolar walls, but also with increased surfactant release into alveoli

Question 18

What are the key histological findings in pneumocystis pneumonia

Answer 18

minimal inflammatory infiltrate in alveolar walls, with cotton candy pink foamy exudate (surfactant) in alveolar spaces as bacteria cause increased type II pneumocyte excretion

Question 19

What are the findings of an xray in pneumocystis pneumonia?

Answer 19

Coarse reticular shadow (indicates atypical/interstitial pneumonia), haziness in lung fields as lungs filled with surfactant.

Question 20

What causes aspiration pneumonia?

Answer 20

Aspiration of gastric contents, which introduces acid and gastric flora to the lungs