22 - Pulmonary Embolism Flashcards
What is a pulmonary embolism?
- Blockage in one of the pulmonary arteries in your lungs as embolism has gone through right side of heart to lungs
- 90% come from DVT but patient doesn’t have symptoms of PE
What does this CXR indicate and what symptoms may this patient experience?
Fat embolism syndrome
- Petechial rash, tachycardia, fever, hypoxia
Triad of brain, skin and lung
How may an emboli get to the brain from a DVT?
Paradoxical through a PFO
What is being shown on this CT and what may have caused it?
- Air embolism that will cause midline shift and infarct
- Iatrogenic due to central venous catheter or haemodialysis catheter
What are some risk factors for a PE?
Same as DVT, anything that causes two of Virchow’s triad
Why are you at higher risk of PE when you are obese?
- Impaired circulation and increased synthesis of clotting factors by the liver due to increased oestrogen so hypercoagulable
What are some genetic diseases that lead to a hypercoaguable state?
- Antithrombin II deficiency
- Protein C or S deficiency
- Factor V Leiden
- Homocystinuria
What are some of the consequences of a PE?
- Hypoxia due to V/Q mismatch
- Right ventricular strain/failure due to rise in pulmonary artery pressure so drop in cardiac output
- Poorly perfused lung may undergo infarction but usually doesn’t as bronchial arteries and airways get oxygen to tissue
What are some symptoms of a PE?
- Dyspnea sudden
- Pleuritic chest pain sudden
- Cough
- Haemoptysis if infarction
- Low grade fever
- Leg pain
What are some signs of PE?
- Tachypnea
- Rales or decrease breath sounds
- Accentuated second heart sound
- Tachycardia
- Cardiac murmur
- Cyanosis
What are some differentials for sudden onset pleuritic chest pain/breathlessness?
What are some investigations you may do if you suspect a PE?
- ABG for hypoxaemia and hypocapnia
- CXR often normal but rules out other diagnoses
- ECG S1Q3T3 and sinus tachycardia
- D-dimers with Well’s criteria
- CTPA
What ECG changes may you see in a PE?
S1Q3T3
- Large S wave in lead I
- Q wave in lead III
- Inverted T wave in lead III
How do we treat a confirmed PE?
- Low molecular weight heparin to stop clot propogating and allow body to break it down
- Oral anticoagulant next e.g warfarin, rivaroxaban
Why do we need to be careful when administering IV heparin?
- Heparin-induced thrombocytopenia
- Abnormal antibodies activate platelets and cause lots of thromboembolic episodes so can cause MIs and strokes
What should you do long term if a patient has had a PE but cannot take anticoagulants, e.g because they have oesophageal varices or previous haemorraghic stroke?
B
Hypercoagulability due to malignancy
