Signs and Symptoms of Pulmonary Embolism
Authors: Dean Percy Yan Yu Reviewers: Tristan Jones Julia Heighton Man-Chiu Poon* Lynn Savoie* * MD at time of publication
Notes
• One of the most under- diagnosed conditions, typically asymptomatic, with tachycardia often being the only sign
• Consider DVT and PE as one disease: if PE is suspected, look for signs and symptoms of DVT
• Absence of DVT does not rule out PE
Virchow’s Triad: hypercoagulable state, venous stasis, vessel injury (*see Suspected DVT)
Deep Vein Thrombosis – popliteal, femoral, iliac veins Clot migrates to IVCàright atrium of heartàright
ventricleàpulmonary vasculature
Large clots (saddle emboli) are lodged in pulmonary arteries
Small clots are lodged in pulmonary arterioles
Saddle embolus (pulmonary artery obstruction)
Back-up of blood into right heart
Right heart strain
↓ CO2 delivery to the lungs for exhalation
Less CO2 exhaled, CO2 builds up in the blood, triggers medullary chemoreceptors to ↑ respiratory rate
Well-ventilated (V) areas of lung do not receive adequate blood supply (Q); vice versa
V/Q mismatch
On V/Q scan
Signals brain to ↑ heart rate
Ischemic tissue becomes inflamed and adheres to pleura
Pleural friction rub
Sandpaper-like sound heard on auscultation
Pleuritic chest pain
Focal, localized chest pain that occurs with each breath
Clot ↓ pulmonary arterial/arteriolar blood flow
↓ delivery of deoxygenated blood to alveoli for oxygenation
Low O2 in blood (↓ O2 saturation) is detected by aortic/carotid chemoreceptors
Signals brain to ↑ respiratory rate
If circulation to lung periphery is cut off, sub-pleural lung tissue can become ischemic and infarct
Irritation of somatic sensory nerve endings on the parietal pleural membrane
Pain stimulates adrenergic response
Tachycardia
Dyspnea/shortness of breath (SOB)
Most sensitive indicator of PE, but not very specific
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Re-Published June 15, 2019 on www.thecalgaryguide.com