Pulmonary Vascular Diseases

Question 1

Pulmonary vascular diseases (4)

Answer 1

1. Pulmonary Edema
2. Pulmonary Hypertension
3. Pulmonary Emboli
4. Pulmonary Vasculitis

Question 2

Causes of pulmonary edema (3)

Answer 2

1. Pulmonary capillary congestion due to LHF (increased cap hydrostatic pressure + decreased cap oncotic pressure + lymphatic obstruction)
2. Microvascular injury - infections, inhaled toxic gases, drugs, chemicals, shock, trauma, radiation
3. Others - high altitudes, neurogenic

Question 3

Morphology of pulmonary edema

Answer 3

• interstitial edema
• edematous widening of alveolar septa
• accumulation of edema fluid in alveolar spaces
• hemosiderin-laden macrophages (capillary rupture - leakage of red cells - Hb phagocytosed by alveolar macrophages)

Question 4

Definition of pulmonary hypertension

Answer 4

• sustained increased pulmonary arterial pressure resulting in irreversible structural changes in pulmonary arteries
• medial hypertrophy in muscular arteries + intimal proliferation - narrowing/occlusion - reduced cross sectional area - increased pressure

Question 5

Causes of pulmonary hypertension (7)

Answer 5

1. 2 to Chronic lung disease - loss of normal capillaries + hypoxia + structural changes in vessels
2. Primary idiopathic
3. L-sided heart disease
4. Congenital L to R shunts
5. Recurrent pulmonary thromboembolism
6. Pulmonary hypoxia
7. Connective tissue disease

Question 6

Pathogenesis of pulmonary hypertension (4)

Answer 6

1. Endothelial dysfunction
2. Decreased NO production & increased endothelin release - vasoconstriction
3. Decreased production of anti-thrombotic factors & endothelial activation - thrombosis
4. Production of cytokines & growth factors - promote migration & prolif of vascular smooth muscle cells & elaboration of ECM
   - also contributed by pulmonary vasospasm, ingestion of certain plant substances, drugs

Question 7

Morphology of pulmonary hypertension

Answer 7

• atherosclerosis of pulm artery & major branches-
• medial hypertrophy - increased thickness of SM & intimal proliferation
• luminal occlusion - due to intimal fibrosis
• plexiform lesions - nodular lesions of interlacing blood vessels
• fibrinoid necrosis
• hemorrhage - rupture of vessels

Question 8

Complications of pulmonary hypertension

Answer 8

heart failure secondary to lung disease = cor pulmonale

Question 9

Causes of pulmonary emboli (3)

Answer 9

1. Thrombus in deep veins of the leg
2. Hypercoagulable states
3. Indwelling central venous lines

Question 10

Effects of pulmonary emboli (4)

Answer 10

1. Large emboli - circulatory collapse
2. Ventilation perfusion mismatch
3. Pulmonary infarction - rare due to protective dual bronchial artery supply - typically hemorrhagic infarct, wedge shaped peripheral lesions, healing leads to peripheral scar
4. Recurrent small thromboemboli - organisation of thrombi in small arteries - occlusion - increase pulmonary vascular resistance/progressive reduction in pulmonary vasculature - pulmonary hypertension/chronic cor pulmonale

Question 11

Features of pulmonary vasculitis

Answer 11

• uncommon, usually part of systemic disease
• inflammatory destruction of blood vessels - bleeding
• eg Wegener’s granulomatosis, Churg-Strauss syndrome