Pathology and Histology

Question 1

What is pneumonia?

Answer 1

Infection involving the distal aspects of the respiratory tree including localised oedema

Question 2

What is lobar pneumonia?

Answer 2

Pneumonia involving a complete lung lobe

Question 3

What are the different types of pneumonia (based on where infection was acquired)?

Answer 3

1. Community acquires
2. Hospital acquired
3. Aspiration

Question 4

During a classical acute inflammatory response what are the main stages in a pneumonia?

Answer 4

1. Exudation - emission of fibrin- rich through pores or wounds
2. Infiltration by neutrophils
3. Infiltration by macrophages
4. Resolution

Question 5

Why is pneumonia potentially able to cause long term damage?

Answer 5

Organisation of tissues during healing can cause fibrosis scarring
Abscesses can form
Bronchiectasis can occur- abnormal dilation of bronchi
Empyema- collection of pus in the body cavity most commonly in the pleura

Question 6

What is bronchopneumonia ?

Answer 6

This is when infection causing pneumonia starts in the airways and proceeds to infect the alveolar lung
This is common when the patient has pre-existing disease

Question 7

Which pathogens can cause bronchopneumonia ?

Answer 7

Strep. pneumonia, Haemophilius influenza, S. aureus, anaerobes and coliforms

Question 8

What is an abscess?

Answer 8

A local collection of pus
Can cause chronic malaise and fever
Caused by aspiration of pathogens

Question 9

What is bronchiestasis?

Answer 9

Fixed dilation of bronchi

This is due to fibrous scarring after infection, or chronic obstruction

Question 10

Which pathogen is most likely to cause TB?

Answer 10

Mycobacterium tuberculosis

M.ovis can also cause Tb

Question 11

What is a key sign of TB?

Answer 11

Granuloma formation
Caseating “cheesy” necrosis
This is due to delayed hypersensitivity (type IV) reaction

Question 12

What is primary TB?

Answer 12

The first exposure to TB
The pathogen is phagocytksed and taken to hilarious lymph nodes which provokes an immune reaction leading to a granulomatous response

Question 13

What is secondary TB?

Answer 13

This is the secondary encounter with TB and involves reinfection and reactivation
A degree of immunity will be present
Generally the disease will still remain localised to the lung pieces

Question 14

Describe the tissue changes in primary TB

Answer 14

Small focuses (John focuses) occur which are small lesions caused by the mycobacterium
Large hilar lymphnodes will develop due to the granulomas forming

Question 15

Describe the changes in secondary TB

Answer 15

Fibrosis and caveatting of apical lesions will occur

This worsens the damage already present

Question 16

Why may reactivation with TB occur?

Answer 16

Decrease in T cell function due to :

• Age
• Immunosuppression due to disease (HIV)
• Immunosuppression due to therapy- steroids, chemo

Question 17

How may a patient with TB be diagnosed ?

Answer 17

• History
• Broncho-alveolar lavage- bronchoscope is. passed into the lungs and squirts fluff into the lungs which is subsequently collected for study
• Biopsy

Question 18

What is pulmonary interstitium?

Answer 18

This is where gas exchange occurs

Contains alveolar type I and II cells as well as thin connective tissue high in elastin

Question 19

How does ILD commence?

Answer 19

Any form of injury that leads to alveoli’s- inflammation of the alveoli

Question 20

What are the two umbrella causes for ILD?

Answer 20

1. Environmental - minerals(asbestos), drugs, radiation

2. Idiopathic

Question 21

How can ILD be diagnosed?

Answer 21

• Tranbronchial biopsy
• Thoracoscopic biopsy - more invasive- thoracoscopre enters through incision between the ribs allowing for visual inspection of the lungs