Resp Path 2 - Vascular Disease of Lung

Question 1

What is meant by the dual blood supply of the lungs?

Answer 1

Blood supply from bronchial artery and pulmonary artery.

Question 2

What is the aetiology of PE?

Answer 2

Usually thromboembolus, can also be tissue (bone marrow postop), tumour embolism, foreign body, fat embolus (long bone fracture), air/gas.

Question 3

Where do pulmonary thromboemboli usually originate?

Answer 3

Deep veins of legs/pelvis or right side of heart.

Question 4

Risk factors for PE?

Answer 4

Immobilisation, heart disease, age, OCP, tissue injury, late pregnancy.

Question 5

Describe the effects of a saddle embolus?

Answer 5

Sudden death due to electromechanical dissociation (no blood in pulmonary circulation), or due to acute cor pulmonale/right-sided heart failure.

Question 6

What is the status of PE regarding infarction?

Answer 6

It causes infarct in 10% of cases, usually in patients w/ compromised pulmonary circulation, infarction is haemorrhagic.

Question 7

Why is PE diagnosis difficult?

Answer 7

Symptoms are often non-specific: dyspnoea, cough, fever, haemoptysis, pleurisy, tachycardia.

Question 8

What is the risk factor with recurrent /multiple small thromboemboli?

Answer 8

Pulmonary HTN

Question 9

Define pulmonary oedema?

Answer 9

Fluid accumulation in the pulmonary interstitium and alveolar airspaces.

Question 10

What are the three main causes of pulmonary oedema?

Answer 10

1. ) Increased microvascular pressure –> LVF, aortic/mitral valve disease,
2. ) Microvascular damage –> infectious and toxic agents, radiation, trauma, shock, drowning
3. ) Other –> neurogenic, high altitude.

Question 11

Define pulmonary HTN?

Answer 11

Systolic BP >30mmHg (N=25), mean arterial > 25mmHg (N=18),

Question 12

Describe the aetiology of pulmonary HTN?

Answer 12

Primary/idiopathic - rare
Secondary - 1.) decreased cross-sectional area of pulmonary vascular bed (Parenchymal disease)
2.) increased vascular blood flow (congenital heart defect with L to R shunt).
3.) increased blood viscosity –> polycythaemia rubra vera
4.) increased pulmonary vascular resistance.

Question 13

Pathological findings in HTN?

Answer 13

Arterioles and small arteries –> Thickening and medial hypertrphy of artery walls.
Medium sized muscular arteries –> myointimal and SM cell proliferation which thickens intima and media.
Main pulmonary arteries –> atheroma
Advanced pulmonary HTN –> plexiform lesions and vascular wall necrosis.

Question 14

Clinical findings in pulmonary HTN?

Answer 14

Intense fatigue & SOB, cor pulmonale, pulmonary artery atheroma.