Pulmonary embolism Flashcards
What is a pulmonary embolism?
Occlusion of the pulmonary vasculature by a clot.
Often occurs from a DVT that has become dislodged and forms and embolus that lodges in the pulmonary arterial vasculature, blocking the vessels.
What are the signs and symptoms of pulmonary embolism?
Breathlessness: this may be of sudden onset or progressive. Tachypnoea. Pleuritic chest pain. Cyanosis. Haemoptysis.
What are the causes of pulmonary embolism?
DVT. Air embolus. Fat embolus. Amniotic fluid embolus. Foreign material introduced via IV drug use.
What are the complications of pulmonary embolism?
Sudden death. Arrhythmia. Pulmonary infarction. Pleural effusion. Paradoxical embolism. Pulmonary hypertension.
What is the pathophysiology of pulmonary embolism?
The extent of thrombus may be classified into small-medium, multiple and massive PE. Symptom correlation depends on where the pulmonary circulation is occluded.
3 pathways:
1) Platelet factor release: serotonin and thromboxane A2 cause vasoconstriction.
2) Decreased alveolar perfusion: lung is under perfused and this leads to diminished gas exchange.
3) Decreased surfactant: this leads to ventilation/perfusion mismatch, hyperaemia and dyspnoea.
What investigations are conducted for suspected PE?
D-dimer: sensitive but not specific, negative result used to rule out PE.
Thrombophilia screening: in patients <50 years with recurrent PE.
CXR: usually normal.
ECG: sinus tachycardia, S1Q3T3 pattern is classical but rare, excludes MI.
ABG: hypoxaemia.
CT, pulmonary angiography.
V/Q scan.
The Wells Score may be used to calculate the risk of PE.
What is the acute treatment for pulmonary embolism?
Oxygen.
IV fluids.
Thrombolysis therapy if indicated, e.g. alteplase if massive PE or haemodynamically unstable.
Low molecular weight heparin.
What is the long-term management for pulmonary embolism?
Anticoagulation.
Inferior vena cava filter.
