PE depends on its severity. The following clinical presentations are common and include:
1) Acute unexplained dyspnea,
2) Pulmonary infarction or hemorrhage,
3) Acute right ventricular failure, and
4) Chronic pulmonary arterial hypertension.Acute unexplained dyspnea is often the presenting symptom of PE, The most frequently encountered physical finding is tachypnea, with a respiratory rate at rest greater than 16 per minute. Sinus tachycardia often accompanies dyspnea and can be a clue to the diagnosis of PE. Unexplained pallor, fatigue, apprehension can be other associated symptoms. The diagnosis of PE in this group of patients is many Limes missed and requires a high index of suspicion in potential clinical situation.
Pulmonary infarction or hemorrhage is an uncommon presentation of PE. These patients present with pleural pain, haemoptysis, dyspnea, cough and fever. These cases can often be confused as having chest infection, pneumonia or other form of lung disease. Crepitations in lungs and pleural iub are often present in this group of patients.Acute light ventiicular failure can be a presentation in patients with massive occlusion of pulmonary arterial tree. This group usually presents as an emergency. These patients present either with chest pain, syncope, acute dyspilea or in a state of shock with all its signs (pallol; tachypnea, tachycardia, cyanosis, hypotension, gallop rhythm and other features of circulatory failure). This group of patients may die suddenly, develop refractoiy shock or improve if provided with necessary medical assistance. In . this group of patients the initial differential diagnosis may be a cardiogenic shock secondary to myocardial infarction.Chronic pulmonary arterial l~yperlension (PAH) can be a presentation in those patients complain of where the initial diagnosis of PE is missed. These patients us~~ally dyspnea, fatigue and on clinical examination have signs of PAH. In some patients multiple episodes of embolism can produce chronic PAH with signs of right ventricular failure.As described above, PE can present with a variety of cli'nical syndromes. It will be worth repeating that presence of following signs in a susceptible patient should lead lo a search for PE. These are suinmarized in Table .
1) Unexplained sinus tachycardia or tachypnea,
2) ' Fever, crepitations, pleural rub,
3) Lower limb oedema / calf tenderness,
5) Hypotension, shock, cyanosis (central or peripheral),
Evidence of right ventricular failure (elevated venous pressure, gallop rhythm, tricuspid regurgitation murmur), and
6) Features of pulmonary arterial hypertension (parastarnal heave, loud P2 etc.).
4)Differential diagnosis of PE is broad and covers a spectruin from life - threatening disease such as acute myocardial infarction to innocuous anxiety states. The common coilditions considered in differential diagnosis are shown in Table ,
Investigations
1) X-ray Chest: The chest X-ray is a useful investigation but may not provide diagnostic information. The X-ray is often helpful in excluding lung disease like pneumonia as a cause of acute dyspnea.The chest X-ray can be helpful in establishing the diagnosis of pulmonay infarction by demonstrating pleural effusion, an infiltrate, atelectasis, or an elevated hemidiaphragm. In patients with chronic PAH, the X However, it should be enlphasized that a ~lormal chest X-ray does not rule out diagnosis of PE.
2) Electrocnrdiogranz (ECG): The ECG is a sinlple and usefill lesl bul may no1 provide diagnostic information in each and every,case. A normal electrocardiogram does not exclude PE.The presence of light ventricular abnormality, as demonstrated by S IQ3T3, right bundle branch block, right axis deviation, or atrial abnormality, are seen in only 26 per cent of patients with PE. . Atrial fibrillation, supraventricular arrhyth~nins and ST -T changes in anterior and inferior leads are also seen.Arterial Blood Gases (ABG): Analysis of ABG is helpful in supporting the diagnosis of PE. Finding of low PO,, low CO, and respiratory alkalosis area pointers to the diagnosis of PE in a patient with iisk factors for its development.It should be remembered that conditions which mimic PE like pneumonia, severe chest infections or chronic obstructive lung disease (COPD) can also cause low PO,.Pulse oxymetry is extremely insensitive in inaking a diagnosis of PE and can be normal in many patients.
1) Acute unexplained dyspnea,
2) Pulmonary infarction or hemorrhage,
3) Acute right ventricular failure, and
4) Chronic pulmonary arterial hypertension.Acute unexplained dyspnea is often the presenting symptom of PE, The most frequently encountered physical finding is tachypnea, with a respiratory rate at rest greater than 16 per minute. Sinus tachycardia often accompanies dyspnea and can be a clue to the diagnosis of PE. Unexplained pallor, fatigue, apprehension can be other associated symptoms. The diagnosis of PE in this group of patients is many Limes missed and requires a high index of suspicion in potential clinical situation.
Pulmonary infarction or hemorrhage is an uncommon presentation of PE. These patients present with pleural pain, haemoptysis, dyspnea, cough and fever. These cases can often be confused as having chest infection, pneumonia or other form of lung disease. Crepitations in lungs and pleural iub are often present in this group of patients.Acute light ventiicular failure can be a presentation in patients with massive occlusion of pulmonary arterial tree. This group usually presents as an emergency. These patients present either with chest pain, syncope, acute dyspilea or in a state of shock with all its signs (pallol; tachypnea, tachycardia, cyanosis, hypotension, gallop rhythm and other features of circulatory failure). This group of patients may die suddenly, develop refractoiy shock or improve if provided with necessary medical assistance. In . this group of patients the initial differential diagnosis may be a cardiogenic shock secondary to myocardial infarction.Chronic pulmonary arterial l~yperlension (PAH) can be a presentation in those patients complain of where the initial diagnosis of PE is missed. These patients us~~ally dyspnea, fatigue and on clinical examination have signs of PAH. In some patients multiple episodes of embolism can produce chronic PAH with signs of right ventricular failure.As described above, PE can present with a variety of cli'nical syndromes. It will be worth repeating that presence of following signs in a susceptible patient should lead lo a search for PE. These are suinmarized in Table .
1) Unexplained sinus tachycardia or tachypnea,
2) ' Fever, crepitations, pleural rub,
3) Lower limb oedema / calf tenderness,
5) Hypotension, shock, cyanosis (central or peripheral),
Evidence of right ventricular failure (elevated venous pressure, gallop rhythm, tricuspid regurgitation murmur), and
6) Features of pulmonary arterial hypertension (parastarnal heave, loud P2 etc.).
4)Differential diagnosis of PE is broad and covers a spectruin from life - threatening disease such as acute myocardial infarction to innocuous anxiety states. The common coilditions considered in differential diagnosis are shown in Table ,
Investigations
1) X-ray Chest: The chest X-ray is a useful investigation but may not provide diagnostic information. The X-ray is often helpful in excluding lung disease like pneumonia as a cause of acute dyspnea.The chest X-ray can be helpful in establishing the diagnosis of pulmonay infarction by demonstrating pleural effusion, an infiltrate, atelectasis, or an elevated hemidiaphragm. In patients with chronic PAH, the X However, it should be enlphasized that a ~lormal chest X-ray does not rule out diagnosis of PE.
2) Electrocnrdiogranz (ECG): The ECG is a sinlple and usefill lesl bul may no1 provide diagnostic information in each and every,case. A normal electrocardiogram does not exclude PE.The presence of light ventricular abnormality, as demonstrated by S IQ3T3, right bundle branch block, right axis deviation, or atrial abnormality, are seen in only 26 per cent of patients with PE. . Atrial fibrillation, supraventricular arrhyth~nins and ST -T changes in anterior and inferior leads are also seen.Arterial Blood Gases (ABG): Analysis of ABG is helpful in supporting the diagnosis of PE. Finding of low PO,, low CO, and respiratory alkalosis area pointers to the diagnosis of PE in a patient with iisk factors for its development.It should be remembered that conditions which mimic PE like pneumonia, severe chest infections or chronic obstructive lung disease (COPD) can also cause low PO,.Pulse oxymetry is extremely insensitive in inaking a diagnosis of PE and can be normal in many patients.
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| ECG Pattern Seen in Patients wit11 Pulmoliary Enibolism |
4 ) Echocardiography: Echocardiography is insensitive for the visualization of thrombi in pulmonary circulation but is a rapid, practical and sensitive technique for detection of light ventricular overload among patients with established and large PE. Echocardiographic detection of right ventricular dysfunction at the time of presentation with PE is useful for risk stratification and prognoslication. For those patients in whom transthoracic imaging is unsatisfactory, transesophageal echocardiography may be useful.
5 ) Ventilation Perfusion Lung Scan (VQ scan): The VQ scan used lo be considesed an impoi-tant investigation for inany years. However, the availability of computed tomography (CT) has reduced its utility. In today's date, if facilities are available, CT is usually prefel-sed for diagnosis. The use of VQ scan is reserved for patients in whoin inotion arliract or poor right heart fiinction limit the quality of CT examination and those with conhaindication to intravenous radiography contrast.
5 ) Ventilation Perfusion Lung Scan (VQ scan): The VQ scan used lo be considesed an impoi-tant investigation for inany years. However, the availability of computed tomography (CT) has reduced its utility. In today's date, if facilities are available, CT is usually prefel-sed for diagnosis. The use of VQ scan is reserved for patients in whoin inotion arliract or poor right heart fiinction limit the quality of CT examination and those with conhaindication to intravenous radiography contrast.
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| Ventilation Perfusion Misnlutch in lDu1monary E~l~bulisrn |
6 ) Pulmonary Angiography: Standard conlrast pulmonary angiography has been collsidercd the gold standard for accurate in vivo diagnosis or exclusion of PE.With availability of digital subtraction angiography, nonionic contrast media, improved techniques and experience, it can be performed expeditiously and safely jn most patients. Angiography is most useful when a diagnostic dilemma persists despite the use of non-invasive tests. This situation is most~common when the diagnostic test results are negative or unbigunous in the presence of high clinical suspicion for PE. Pulmoilary angiography is obviously also required when interventions are planned such as suction catheter embolectomy,mechanical clot fragmentation, or catheter - directed thrombolysis.Diagnosis of PE is entertained by demonstrating filling defects (clots), abivpt cut off or tapeling of pulmonary arteries and by ancillary findings such as webs',dilated main and branch pulmonary arteries. Figure shows filling defect in right pulmonary artery in a patient with PE.
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| Filling Defect in Right Pulmonary Artery in Pulmonnry Embolism |
7 ) D-dimer Assay: D-dimes is a blood test which can be rapidly performed and is utilized these days as a screening test for venous thron~boembolisrn (deep venous thrombosis, or PE). D-dimer is a fibrin specific degradation produce that detects cross-linked fibrin resulting from endogenous fibrinolysis. In the presence of a11 acute thrombo-einbolic event (like DVT or PE) the simultaleous activation of coagulation factors and fibrinolytic enzymes leads to increased concentration of D-dimer.Normal values of this protein have high negative predictive value, that is a patient whose D-dinler is less than 500 micrograms is unlikely to have PE. On ljle other hand, elevated D-diiner levels do not necessarily indicate PE and can be elevated in DVT, infections, inflammation, necrosis, trauma, and cancer etc.
8) Contputed Tomographic (CT) Prtlmonary Angiography (PA): CTPA has gained acceptance as a first-line imaging study in cases of suspected acute PE, replacing traditional V/Q scintigraphy at many institutions, CTPA has also reduced the need for invasive pulmonary angiography.CTPA provides visualization of the pulmonaiy arterial system in the axial plane,and multiplanar and three dinlensional reconstructions can be generated from raw data to enhance diagnostic accuracy. The cardinal sign of acute PE on CTPA is an intravascular filling defect in a pulmonary artery that partially or conlpletely occludes the vessel and is often associated wilh increased d i q e t e r of the affected vessel. The most specific sign of acute PE is a filling defect that forms acute angles with the vessel wall.Even spiral CT can diagnose PE and figure 4 shows example of a patient where thrombi are delnonstrated in both pulmonary arteries in a patient with PE. The other advantage of spiral CT technique is its ability to diagnose or exclude other lung disorders which can mimic PE. A reliable diagnosis of lung consolidation,collapse, ei'fusion, abscess, tumors and pneumothorax can be made by CT scan technique.
8) Contputed Tomographic (CT) Prtlmonary Angiography (PA): CTPA has gained acceptance as a first-line imaging study in cases of suspected acute PE, replacing traditional V/Q scintigraphy at many institutions, CTPA has also reduced the need for invasive pulmonary angiography.CTPA provides visualization of the pulmonaiy arterial system in the axial plane,and multiplanar and three dinlensional reconstructions can be generated from raw data to enhance diagnostic accuracy. The cardinal sign of acute PE on CTPA is an intravascular filling defect in a pulmonary artery that partially or conlpletely occludes the vessel and is often associated wilh increased d i q e t e r of the affected vessel. The most specific sign of acute PE is a filling defect that forms acute angles with the vessel wall.Even spiral CT can diagnose PE and figure 4 shows example of a patient where thrombi are delnonstrated in both pulmonary arteries in a patient with PE. The other advantage of spiral CT technique is its ability to diagnose or exclude other lung disorders which can mimic PE. A reliable diagnosis of lung consolidation,collapse, ei'fusion, abscess, tumors and pneumothorax can be made by CT scan technique.
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| Pntleut wit11 thrombi in least pulrnol~ary arteries |
9 ) Magnetic Resonance (MR) Pulmonary Angiograplzy: This technique has developed significantly in thc last 10 years. However, there rue still several problems including accluisition of good iinages in breatliless patients. At the present time CTPA is considered supcrior to MR angiography.
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