Pulmonary Embolism

RISK FACTORS:
  • PE usually results from a blood clot in the leg that travels to the lung.The risk of blood clots is increased by :
  • Cancer, 
  • Prolonged bed rest, 
  • Smoking, 
  • Stroke, 
  • Large veins of lower limb
  • Certain genetic conditions, 
  • Estrogen-based medication, 
  • Pregnancy, 
  • Obesity, and 
  • After some types of surgery
SYMPTOMS:
  • Dyspnea (shortness of breath), pain, haemoptysis
  • Tachypnea (rapid breathing):Activation of juxtapulmonary-capillary receptors during pulmonary embolism 
  • Chest pain of a "pleuritic" nature (worsened by breathing), 
  • Cough and hemoptysis (coughing up blood)
  • More severe cases can include signs such as 
  1. cyanosis (blue discoloration, usually of the lips and fingers), 
  2. Collapse, and circulatory instability because of decreased blood flow through the lungs and into the left side of the heart.
  • About 15% of all cases of sudden death are attributable to PE.
  • The most common cause of preventable Hospital Death is Pulmonary embolism
DIAGNOSIS:
  • Computed tomography (CT) pulmonary angiogram(Best method ):
  1. Intraluminal filling defect in a lobar or main pulmonary artery
  2. Intraluminal filling defect in a segmental pulmonary artery and moderate or high CPTP (clinical pre-test probability.)
  • Ventilation-perfusion scan(Gold standard): High probability scan and moderate or high CPTP
  1. Positive diagnostic test for deep vein thrombosis (with a non-diagnostic ventilation-perfusion scan or CT pulmonary angiogram)
  2. In pulmonary embolism, findings in perfusion scan are Perfusion segmental defect or Perfusion defect with normal lung scan & radiography
  • D-dimer test:
  1. Negative test which has high sensitivity (>95%) and low or moderate CPTP
  2. Negative test which has moderately high sensitivity (>85%) and low CPTP
  •  Non-diagnostic ventilation-perfusion scan or suboptimal CT pulmonary angiogram and normal venous ultrasound of the proximal veins and Low CPTP or Negative D-dimer test which has moderately high sensitivity (≥85%) or Normal repeat venous ultrasound scans of the proximal veins after 7 and 14 daysv 
  • In acute pulmonary embolism Sinus tachycardia is the most frequent ECG finding
  • ECG:right ventricular dilatation and tricuspid regurgitation
  1. ECG pattern seen in pulmonary embolism is S1Q3T3
  • X-ray:
  1. Hamptons' hump is one of the classic radiographic findings of pulmonary embolism.
  • It appears as a peripheral wedge shaped opacity on chest x rays. It is d/t pulmonary infarct. Other signs of pulmonary embolism on chest x-ray
  1. Westermark's sign - it's a.focal area of oligetnia due to vesoconstriction distal to embolus.
  2. Palla's sign - enlarged right descending pulmonary artery.
TREATMENT:
  • Thrombolytic therapy in pulmonary embolism is used for patients who present with hemodynamic compromise, patients who develop hemodynamic compromise during conventional therapy with heparin, and patients with embolism associated with intracavitary right-heart thrombi. 
  • The anticoagulant effect of heparin in pulmonary embolism would be most appropriately assessed by Activated partial thromboplastin time
Exam Question
  • Best investigation when there is clinical suspicion of pulmonary embolism in a patient is Multi detector CT angiography
  • Hampton's hump is seen in chest X-ray in Pulmonary embolism
  • Test results that confirm or exclude pulmonary embolism are Perfusion scan & CT pulmonary angiogram
  • Hampton's hump, Westermark sign & Fleischner sign are radiological sign present in a young lady with symptoms suggestive of pulmonary embolism
  • The anticoagulant effect of heparin in pulmonary embolism would be most appropriately assessed by Activated partial thromboplastin time
  • Treatment of choice in a patient of acute pulmonary embolism with right ventricular hypokinesis and compromised cardiac output but normal blood pressure is Thrombolytic agent Obesity, Malignancy & Protein S deficiency may predispose to pulmonary embolism 
  • In acute pulmonary embolism Sinus tachycardia is the most frequent ECG finding
  • Activation of juxtapulmonary-capillary receptors during pulmonary embolism causes Tachypnea 
  • The most common source of pulmonary embolism is Large veins of lower limb
  • D-dimer is the most sensitive test for Pulmonary embolism
  • In pulmonary embolism, findings in perfusion scan are Perfusion segmental defect or Perfusion defect with normal lung scan & radiography
  • Best method to diagnose pulmonary embolism Pulmonary angiography
  • Gold standard for diagnosing pulmonary embolism Ventilation perfusion scan
  • The sequence of symptoms in pulmonary embolism is Dysponea, pain, haemoptysis
  • In pulmonary embolism, fibrinolytic therapy is responsible for Risk of haemorrhage
  • A patient undergoing surgery suddenly develops hypotension & The monitor shows that the end tidal CO, has decreased abruptly by 155 mm Hg is diagnosed to have Pulmonary embolism
  • The most common cause of preventable Hospital Death is Pulmonary embolism
  • ECG pattern seen in pulmonary embolism is S1Q3T3

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