14 - Pathology of Obstructive Pulmonary Diseases

Question 1

What are the different pathologic forms of emphysema? What are their characteristics?

Answer 1

Centriacinar

• smokers
• upper lobes
• begins in respiratory bronchiole

Panacinar

• alpha-antitrypsin deficiency
• lower lobes
• begins with alveoli/alveolar ducts

Distal acinar / paraseptal

• near pleura and septa
• upper lobes
• forms bulla that may rupture
• pathogenesis may be previous infection with abnormal healing

Irregular

• focal (near a scar)
• clinically insignificant

Question 2

What is the anatomic definition of emphysema?

Answer 2

Irreversible airspace enlargement distal to terminal bronchiole with alveolar destruction and no fibrosis (if alveolar septal fibrosis is present, an additional process must be present)

Question 3

What are the gross and histological findings associated with emphysema?

Answer 3

Gross

• cystic areas (blebs and bullae)
• centriacinar: emphysematous areas separated by normal lung
• panacinar - entire pulmonary acinus is involved

Histology
- some residual normal lung with the majority of the field taken up by irregularly enlarged air spaces (absent alveoli)

Question 4

What histological changes are seen in chronic bronchitis?

Answer 4

• increased size and number of submucosal glands –> increased Reid index (> 0.4)
• goblet cell hyperplasia
• chronic inflammation with lymphocytes and neutrophils
• goblet cells extend down to the level of the bronchiole

Question 5

Emphysema affects [small/medium/large] airways. Chronic bronchitis affects [small/medium/large] airways.

Answer 5

Both affect small airways

Question 6

What are the complications of COPD?

Answer 6

• pulmonary hypertension (from hypoxemia and destruction of alveolar capillaries)
• cor pulmonale
• pneumothorax

Question 7

What histological changes are seen in asthma?

Answer 7

• remodeling
• increased goblet cells
• submucosal gland hyperplasia
• basement membrane thickening
• smooth muscle hypertrophy
• airway wall infiltrated with eosinophils and mast cells
• mucus plugs can completely obstruct airways

Question 8

Chronic bronchitis and asthma may appear histologically similar. What distinguishes asthma from bronchitis?

Answer 8

Asthma has eosinophils, mast cells, and basement membrane thickening. Chronic bronchitis does not

Question 9

What are the gross pathological and histological findings associated with bronchiectasis?

Answer 9

Gross

• permanently dilated airways from chronic necrotizing infection
• mucoid plugs

Histological

• acute bronchopneumonia with neutrophils
• ulceration of bronchial mucosa
• acute and chronic inflammation
• subepithelial fibrosis
• squamous metaplasia