L4 Chronic bronchitis and emphysema

Question 1

What does the secondary lobule is made of ?

Answer 1

Secondary lobule is made of many acinus and it is surrounded by CT

Question 2

What are the type of lymphocytes and inflammatory cells in both asthma and COPD ?

Answer 2

Asthma :

- CD4+ —

Question 3

Where do emphysema and chronic bronchitis work ?

Answer 3

• Chronic bronchitis usually affects the airways leading to irreversible narrowing by hyper secretion of mucus that with time will undergo fibrosis
• Emphysema works on the respiratory unit as whole and destroying the elastic tissue that normally open the airways during exhalation which will trap the air

Question 4

What is the mechanism of obstruction in emphysema?

Answer 4

• Alveolar wall destruction
• loss of elastic tissue in the walls of alveoli
• loss of radial traction of respiratory bronchioles
• bronchioles collapse during expiration
• functional airflow obstruction

Question 5

Compare between emphysema and CB in relation to :

• cough
• dyspnea
• hypoxemia
• cor pulmonale
• heart failure

Answer 5

Emphysema:

• not productive cough
• early dyspnea
• late hypoxemia
• cor pulmonale is rare
• heart is small

CB

• productive cough
• late dyspnea
• early hypoxemia
• cor pulmonale is common
• heart failure with large heart

Question 6

Why mucus hypersecretion is occurring as the earliest sign of CB ?

Answer 6

Due to :

1. Goblet cell hyperplasia
2. Submucosal glands enlargement

Question 7

What are the main changes in CB ?

Answer 7

1. Chronic inflammation of large bronchi
2. Narrowing of bronchioles ( due to mucus hypersecretion then fibrosis after a while )
3. Epithelium metaplasia ( from stratified to squamous that will impair mucociliary action due to ROS from cigarette smoking )

Question 8

When reid index is considered as pathological ?

Answer 8

If it was more than 0.4

Question 9

How cigarette smoking is causing CB and emphysema?

Answer 9

1. In CB :
   - smoking will produce ROS that will cause epithelium metaplasia from stratified columnar to stratified squamous which will impair the mucociliary clearance
2. In emphysema:
   - smoking will produce ROS and activate inflammatory cells that will release mediators and ROS to destroy the respiratory unit ( acinus ) walls so it will collapse easily during expiration

Question 10

What are the main types if emphysema ?

Answer 10

Types based on the part of the acinus that is affected:

– Centriacinar - respiratory bronchiole is affected

– Panacinar - from respiratory bronchiole to alveoli

– Paraseptal - alveolar duct and alveoli ( can cause pneumothorax / bulla emphysema )

– Irregular - can affects any part of the acinus

Question 11

What are the complications of AATD ?

Answer 11

1. Heart failure ( due to pulmonary HTN then cor pulmonale )
2. Respiratory failure
3. Lung collapse due to pneumothorax

Question 12

What is the pathogenesis of bronchiectasis ?

Answer 12

1. Chronic necrotizing infections
2. Destruction of smooth muscle and elastic tissues
3. Abnormal dilatation of bronchi and bronchioles with foul smelling purulent mucus

Question 13

What are the conditions that can cause bronchiectasis?

Answer 13

Any condition that can cause necrotizing infections :

1. COPD ( will more mucus secretion without clearance so more infections )
2. Karatgner syndrome ( in PCD )
3. Cystic fibrosis