Respiratory: Pathology - Diseases of vascular origin

Question 1

What % of pulmonary emboli arise from the deep veins of the leg?

Answer 1

95%

Question 2

Which three conditions predispose to in situ pulmonary thrombosis?

Answer 2

Pulmonary HTN
Pulmonary atherosclerosis
Heart failure

Question 3

How common are large vs medium vs small pulmonary emboli?

Answer 3

Large 5%
Medium 20-35%
Small 60-80%

Question 4

What are the usual clinical consequences of large vs medium vs small pulmonary emboli?

Answer 4

Large: instantaneous death, CV collapse, haemodynamic compromise (if obstructing >60% of the pulmonary circulation)
Medium: haemorrhage or wedge-shaped infarction (less common, due to lung’s dual circulation)
Small: clinically silent or may cause transient chest pain, haemoptysis, small infarctions

Question 5

What histological features differentiates postmortem thrombus from pulmonary embolus?

Answer 5

Pulmonary embolus contains lines of Zahn