Chapter 3

Question 1

What is the pathogenesis of pulmonary edema?

Answer 1

Pulmonary capillary congestion due to left heart failure

Increased fluid in the alveolar wall (interstitium) eventually leads to fluid in alveolar spaces

Capillary rupture may lead to leakage of red cells into interstitium – these red cells are phagocytosed by alveolar macrophages, forming ‘heart failure cells’ containing hemosiderin

Question 2

What are 5 causes of pulmonary hypertension?

Answer 2

1. Secondary to left heart disease (esp mitral valve disease) where pressure is transmitted to the entire pulmonary system
2. Shunts from left to right heart (septal defect)
3. Chronic lung disease, where there is a combination of loss of normal capillaries and hypoxic vasoconstriction of arterioles
4. Sequelae of pulmonary emboli
5. Idiopathic

Question 3

What is the progression of pulmonary hypertension?

Answer 3

1. Sustained increased pulmonary arterial pressure results in irreversible structural changes in pulmonary arteries
2. Medial hypertrophy in muscular arteries and intimal proliferation leads to narrowing/occlusion, reduced cross-sectional area and hence further increased pressure

Question 4

What is cor pulmonale?

Answer 4

Heart failure secondary to lung disease

Question 5

How does cor pulmonale occur?

Answer 5

Long term need to pump at higher pressures eventually causes the right heart to fail

Question 6

What are 4 consequences of pulmonary emboli?

Answer 6

1. Circulatory collapse
2. Infarction of lung (only 10% of cases due to protective bronchial supply)
   - hemorrhagic, wedge shaped peripheral lesions
   - healing leads to peripheral scar
3. VQ mismatch
4. Recurrent small thromboemboli - organisation of thrombi in small arteries = permanent occlusion = decrease in pulmonary vasculature = pulmonary hypertension

Question 7

What is the pathogenesis of pulmonary vasculitis.

Answer 7

Autoimmune inflammatory destruction of blood vessels results in bleeding into lungs.
Repeated episodes lead to vessel damage and cause pulmonary hypertension

Question 8

What lung diseases have prominent lung manifestations?

Answer 8

1. Granulomatosis with polyangiitis (aka Wegener Granulomatosis affecting nose, lungs, kidneys)
2. Eosinophilic granulomatosis with polyangiitis (aka Churg-Strauss syndrome) (infiltration of many organs by eosinophils. patients usually also have asthma)

Question 9

What is atelectasis?

Answer 9

Collapse of the lung.

Inadequate expansion of the lung leads to loss of lung volume

Question 10

What causes atelectasis?

Answer 10

1. Resorption Atelectasis: Airway Obstruction
2. Compression Atelectasis: Air (pneumothorax) or fluid (effusion) in pleural space with compression of lung; post op poor lung expansion
3. Contraction atelectasis: Scarring of lung or pleura (not reversible); loss of normal surfactant