Pulmonary Respiratory Infections

Question 1

Pneumonia

Answer 1

Infection involving distal airspaces of the lungs, usually with inflammatory exudation/ localised oedema

Question 2

Lobar Pneumonia

Answer 2

Confluent consolidation involving a complete lobe

Question 3

What organisms causes lobar pneumonia?

Answer 3

Mainly streptococcus pneumoniae (pneumococcus)

Also can be klebsiella or legionella)

Question 4

Clinical setting of lobar pneumonia

Answer 4

Usually immunity acquired

Usually in otherwise healthy, young adults

Question 5

pathology of lobar pneumonia

Answer 5

Classic acute inflammatory response

• secretion of fibrin-rich fluid
• neutrophil and macrophage infiltration
• resolution

Immune system
- antibodies lead to opsonisation, phagocytosis of bacteria

Question 6

Complications of lobar pneumonia

Answer 6

Organisation eg fibrous scarring
Abscess
Bronchiectasis
Empyema

Question 7

Bronchopneumonia

Answer 7

Infection staring in airways and spreading to adjacent alveolar lung

Question 8

Clinical setting of bronchopneumonia

Answer 8

pre existing disease eg COPD, elderly cardiac failure, flu complication

Question 9

Organisms involved in bronchopneumonia

Answer 9

Streptococcus pneumoniae, haemophiilus influenza, staphylococcus, anaerobes, coliforms

Question 10

Complications of bronchopneumonia

Answer 10

Organisation eg fibrous scarring
Abscess
Bronchiectasis
Empyema

Question 11

Lung abscess

Answer 11

tumour-like localised collection of pus, characterised by chronic malaise and fever

Question 12

Bronchiectasis

Answer 12

Abnormal fixed dilation of bronchi, usually due to fibrous scarring following infection but also in chronic obstruction.

Dilated airways accumulate purulent secretions

Question 13

TB

Answer 13

Chronic mycobacterial infection

Characterused by type 4/ delayed hypersensitivity (granulomas with neurosis)

Question 14

Organisms involved in TB?

Answer 14

M. TB, M. Bovis

Question 15

Pathogenesis of TB

Answer 15

Due to organsims ability to avoid phagocytosis and stimulate a host T-cell response

Question 16

Which of T-cell responses contributes to immunity in TB?

Answer 16

It enhances organisms macrophage ability to kill mycobacteria

Question 17

Which of T-cell responses contributes to hypersensitivity in TB?

Answer 17

It causes granulomatous inflammation, tissue necrosis and scarring

Question 18

When does primary TB occur?

Answer 18

1st exposure, and up to 5 years after

Question 19

Pathology of primary TB

Answer 19

Inhaled organism is phagocytosed and carried to hilarity lymph nodes
Immune activation (few weeks) leads granulomatous response in nodes and lung, usually with killing of organism 
Infection can spread in some cases

Question 20

Pathology of secondary TB

Answer 20

Reactivation of disease in person with some immunity, tends to initially stay localised (generally in apices of lung) which can then spread to airways and/ or bloodstream

Question 21

Tissue changes in primary TB

Answer 21

Small focus in periphery of mid zone of lung and large hilarity nodes which are granulomatous

Question 22

Tissue changes in secondary TB

Answer 22

Fibrosing and cavitating apical lesion

Question 23

Why does disease reactivate?

Answer 23

Decreased T cell function due to age, coincident disease (HIV), immunosuppressive therapy

Also reinfection at a high dose/ with a more virulent organism

Question 24

Diagnosis of TB

Answer 24

Broncho-alveolar lavage
Biopsy
High index of suspicion