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Pulmonary Embolism

Pulmonary embolism is defined as a blockage of a pulmonary artery caused by a thrombus dislodged usually from the deep veins of the lower limbs.


Presentation

The typical presentation of the pulmonary embolism includes sudden onset of pleuritic chest pain, shortness of breath and hypoxia [7]. Most of the patients might have no clinical presentation at all. Symptoms may also vary from patient to patient. Hence, the diagnosis is made in the case of unexplained respiratory problems after excluding the other probable causes.

Other atypical symptoms include hemoptysis, productive cough, abdominal pain, flank pain, seizures, syncope, wheezing, fever and altered level of consciousness [8].

Swelling
  • These include swelling of the leg or along a vein in the leg, pain or tenderness in the leg, a feeling of increased warmth in the area of the leg that's swollen or tender, and red or discolored skin on the affected leg.[web.archive.org]
  • Abstract A young man presented with the severe right upper limb swelling following a heavy weight lifting that was thought to be caused by a biceps tendon rupture.[ncbi.nlm.nih.gov]
  • Also, use compression stockings to prevent chronic (ongoing) swelling in your legs from DVT (as your doctor advises). Contact your doctor right away if you have any signs or symptoms of DVT or PE. Updated: July 1, 2011[web.archive.org]
  • She present swell at knee and calf from postoperative 3 weeks, and developed dyspnea, palpitation, and nausea on 33th day, pulmonary embolism was confirmed with CT angiography at emergency department.[ncbi.nlm.nih.gov]
  • A 71-year-old woman complained of dyspnea and swelling of the left lower limb. Computed tomography revealed filling defects in the pulmonary arteries and deep vein.[ncbi.nlm.nih.gov]
Fever
  • High grade fever is a rare presentation of thromboembolic phenomenon. PATIENT CONCERNS: A middle aged woman presented with high grade fevers. DIAGNOSES: Patient remained febrile despite broad spectrum antibiotics. All cultures were negative.[ncbi.nlm.nih.gov]
  • PATIENT CONCERNS: A 62-year-old male developed fever of unknown origin.[ncbi.nlm.nih.gov]
  • A 47-year-old woman with a medical history of Raynaud's phenomenon presented with fever, cough and shortness of breath. She was found to have left lower lobe consolidation and pleural effusion and was treated as a case of pneumonia.[ncbi.nlm.nih.gov]
  • One month prior to admission, he had developed persistent fever and cough and the diagnosis of CMV infection had been established.[ncbi.nlm.nih.gov]
  • A 14-year-old girl with no previous significant medical history was referred to the ED with pleuritic and chest pain with low-grade fever 4 days before admission. Echography showed a small amount of left pleural effusion.[ncbi.nlm.nih.gov]
Congestive Heart Failure
  • As a result of another medical condition, such as cardiovascular disease (including congestive heart failure, atrial fibrillation and heart attack) or stroke. When clotting factors in the blood are increased, elevated, or in some cases, lowered.[my.clevelandclinic.org]
  • It can mimic pneumonia, congestive heart failure, and a viral illness known as pleurisy.[vascularcures.org]
  • Risk factors include: prolonged bed rest, surgery, childbirth, heart attack, stroke, congestive heart failure, cancer, obesity, a broken hip or leg, oral contraceptives, sickle cell anemia, congenital coagulation disorders, chest trauma, certain congenital[medical-dictionary.thefreedictionary.com]
  • Important prognostic factors associated with death from PE were age older than 70 years, cancer, congestive heart failure, COPD, systolic arterial hypotension, tachypnoea, and right ventricular hypokinesis on echocardiography [ 2 ] .[patient.info]
Prolonged Immobilization
  • RATIONALE: Venous thromboembolism may result from prolong immobilization following intracerebral hemorrhage.[ncbi.nlm.nih.gov]
  • Examples of these include: Prolonged immobilization Extended travel (sitting in a car, airplane, train, etc.)[medicinenet.com]
  • Introduction Definition mechanical obstruction of the pulmonary vascular secondary to a blood clot typically the blood clot is a thromboembolism from a deep vein thrombosis (DVT) Epidemiology risk factors prolonged immobilization ( e.g., long travel)[medbullets.com]
  • ., prolonged immobilization or congestive heart failure).[clinicaladvisor.com]
  • A large pulmonary embolism is usually fatal and is a much-feared complication of recent surgery or pregnancy with prolonged immobilization and inadequate movement of the limbs.[medical-dictionary.thefreedictionary.com]
Fatigue
  • Chronic Thromboembolic Pulmonary Hypertension CTEPH is a syndrome of dyspnea, fatigue, and exercise intolerance caused by proximal thromboembolic obstruction and distal remodeling of the pulmonary circulation that leads to elevated pulmonary artery pressure[doi.org]
Cough
  • Major Signs and Symptoms Signs and symptoms of pulmonary embolism (PE) include unexplained shortness of breath, problems breathing, chest pain, coughing , or coughing up blood. An arrhythmia (irregular heartbeat) also may suggest that you have PE.[web.archive.org]
  • Symptoms of PE include chest pain, shortness of breath, severe cough, coughing up of blood and even sudden death. Pulmonary embolism is the major concern for patients experiencing deep vein thrombosis (DVT).[inovaheart.org]
  • A 47-year-old woman with a medical history of Raynaud's phenomenon presented with fever, cough and shortness of breath. She was found to have left lower lobe consolidation and pleural effusion and was treated as a case of pneumonia.[ncbi.nlm.nih.gov]
  • Despite antibiotic therapy, he remained unwell with rising inflammatory markers, general malaise and persistent cough. He developed stony dull percussion and absent breath sounds to his left mid to lower zones.[ncbi.nlm.nih.gov]
  • One month prior to admission, he had developed persistent fever and cough and the diagnosis of CMV infection had been established.[ncbi.nlm.nih.gov]
Dyspnea
  • The patient suffered dyspnea after undergoing the injection laryngoplasty. Chest embolism computed tomography (CT) scan revealed a new lesion of enhancing materials at the pulmonary vasculature in the right upper lobe.[ncbi.nlm.nih.gov]
  • PATIENTS CONCERNS: Herein, we report a case of high-risk APE with a wide range of manifestations, including chest pain, dyspnea, low-blood pressure, and syncope.[ncbi.nlm.nih.gov]
  • Dyspnea may be absent or occur only with exertion. The onset of dyspnea may occur over seconds to days. Orthopnea occurs with PE as well as heart failure.[ncbi.nlm.nih.gov]
  • He has been living well without dyspnea and the echocardiography showed the normalizations of the once increased pulmonary arterial pressure and the once enlarged right ventricle of his heart.[ncbi.nlm.nih.gov]
  • RATIONALE: Pulmonary embolism (PE) is a common diagnostic consideration for patients who present to the emergency department (ED) with chest pain, dyspnea, or both.[ncbi.nlm.nih.gov]
Hemoptysis
  • Eight variables were included in a block rule: Age 50 years, pulse 100 bpm, SaO(2) 94%, no unilateral leg swelling, no hemoptysis, no recent trauma or surgery, no prior PE or DVT, no hormone use.[ncbi.nlm.nih.gov]
  • The combination of gestalt estimate of low suspicion for PE, together with the PE rule-out criteria [PERC(-): age 50 years, pulse 100 beats min(-1), SaO(2) or 95%, no hemoptysis, no estrogen use, no surgery/trauma requiring hospitalization within 4 weeks[ncbi.nlm.nih.gov]
  • It manifests as pleural chest pain and hemoptysis. In contrast, multiple micro-emboli occlude the capillary beds of the lungs.[symptoma.com]
  • The combination of gestalt estimate of low suspicion for PE, together with the PE rule‐out criteria [PERC( ): age 1 , SaO 2  95%, no hemoptysis, no estrogen use, no surgery/trauma requiring hospitalization within 4 weeks, no prior venous thromboembolism[ingentaconnect.com]
  • […] and assigned scores (in brackets) were included in the clinical prediction rule: Clinical symptoms of DVT (3.0), no alternative diagnosis (3.0), heart rate 100 (1.5), immobilization or surgery in the previous four weeks (1.5), previous DVT/PE (1.5), hemoptysis[ncbi.nlm.nih.gov]
Pneumonia
  • She was found to have left lower lobe consolidation and pleural effusion and was treated as a case of pneumonia. During the hospital course, her respiratory status worsened, and she was intubated on the third hospital day.[ncbi.nlm.nih.gov]
  • We report an unusual presentation of pulmonary embolism (PE) where a 58-year-old man first developed symptoms of community-acquired pneumonia.[ncbi.nlm.nih.gov]
  • Abstract The diagnosis of pulmonary thromboembolism (PE) is often delayed because it is usually misdiagnosed as pneumonia or deep vein thrombosis.[ncbi.nlm.nih.gov]
  • It can mimic pneumonia, congestive heart failure, and a viral illness known as pleurisy.[vascularcures.org]
  • The major utility of the chest film is in finding other causes of the patient’s symptoms (i.e. an infiltrate in pneumonia or absent lung markings in pneumothorax).[clinicaladvisor.com]
Pleural Effusion
  • Echography showed a moderate amount of pleural effusion on both sides and no dilatation of the right cardiac ventricle.[ncbi.nlm.nih.gov]
  • Oligemia (the Westermark sign), prominent central pulmonary artery (the Fleischner sign), pleural-based area of increased opacity (the Hampton hump), vascular redistribution, pleural effusion, elevated diaphragm, and enlarged hilum were also poor predictors[ncbi.nlm.nih.gov]
  • She was found to have left lower lobe consolidation and pleural effusion and was treated as a case of pneumonia. During the hospital course, her respiratory status worsened, and she was intubated on the third hospital day.[ncbi.nlm.nih.gov]
  • In this paper, we will describe an uncommon presentation of lung cancer on a non-smoker middle-aged woman, with recent diagnosis of pulmonary embolism, who develops malignant recurrent pleural effusion, NBTE with cutaneous and neurological manifestations[ncbi.nlm.nih.gov]
Chest Pain
  • The chest pain remained at the same level. On the day of admission, she presented to ED with vomiting, watery diarrhea, abdominal pain, chest pain, and respiratory distress. Laboratory findings showed hypoalbuminemia and proteinuria.[ncbi.nlm.nih.gov]
  • RATIONALE: The differential diagnosis of acute chest pain is very important, and can sometimes be challenging. Related diseases share a number of risk factors, and occasionally, 1 condition causes another disease to develop.[ncbi.nlm.nih.gov]
  • PATIENTS CONCERNS: Herein, we report a case of high-risk APE with a wide range of manifestations, including chest pain, dyspnea, low-blood pressure, and syncope.[ncbi.nlm.nih.gov]
  • RATIONALE: Pulmonary embolism (PE) is a common diagnostic consideration for patients who present to the emergency department (ED) with chest pain, dyspnea, or both.[ncbi.nlm.nih.gov]
  • Physiological changes in pregnancy often cause symptoms that mimic pulmonary embolic disease, such as chest pain and shortness of breath.[doi.org]
Hypotension
  • Ultimately, insufficient cardiac output from the RV causes left ventricular under-filling which results in systemic hypotension and cardiovascular collapse.[ncbi.nlm.nih.gov]
  • KEYWORDS: Cardiopulmonary arrest; Hypotension; Surgical embolectomy; Thrombolysis [Indexed for MEDLINE] Free full text[ncbi.nlm.nih.gov]
  • This case report describes a patient with intraoperative PE presenting with hypotension and hypoxemia for whom the ECG finding of SIQIIITIII was key in identifying acute cor pulmonale.[ncbi.nlm.nih.gov]
  • Suspected pulmonary embolism without shock or hypotension Prognostic assessment Clinical parameters Imaging of the right ventricle by echocardiography or computed tomographic angiography Laboratory biomarkers Markers of right ventricular dysfunction[escardio.org]
  • KEYWORDS: Imaging; Pulmonary embolism; Undifferentiated hypotension[ncbi.nlm.nih.gov]
Tachycardia
  • Tracheobronchomalacia is an uncommon condition, which presents with similar symptoms to pulmonary embolism, including hypoxemia, tachycardia, and shortness of breath.[ncbi.nlm.nih.gov]
  • Increased RV loading causes compensatory RV dilation, impaired contractility, tachycardia, and sympathetic activation.[ncbi.nlm.nih.gov]
  • The most common ECG finding in the setting of a pulmonary embolism is sinus tachycardia. However, the “S1Q3T3” pattern of acute cor pulmonale is classic; this is termed the McGinn-White Sign .[healio.com]
  • Dyspnea (79%) and tachycardia (68%) were the commonest symptom and sign, respectively. D dimer was positive in 96.2% of the cases while nonspecific T inversion in the ECG was seen in 54.7% of the patients.[ncbi.nlm.nih.gov]
  • She had tachypnea, hypotension and tachycardia. Arterial blood gas analysis showed hypoxemia-hypocapnia and D-dimer level was high.[ncbi.nlm.nih.gov]
Cyanosis
  • […] obstruction of a pulmonary artery or one of its branches that is usually produced by a blood clot which has originated in a vein of the leg or pelvis and traveled to the lungs and that is marked by labored breathing, chest pain, fainting, rapid heart rate, cyanosis[merriam-webster.com]
  • The extremities reveal no evidence of edema, cyanosis or clubbing. Patient has negative Homan's Sign. Joint exam revealed shoulder movements complete in range. No warmth or tenderness noted.[meddean.luc.edu]
  • It is characterized by dyspnea, anxiety, sudden chest pain, shock, and cyanosis.[medical-dictionary.thefreedictionary.com]
  • Other signs and symptoms that can occur with pulmonary embolism include: Leg pain or swelling, or both, usually in the calf Clammy or discolored skin (cyanosis) Fever Excessive sweating Rapid or irregular heartbeat Lightheadedness or dizziness When to[mayoclinic.org]
Distended Neck Veins
  • The clinical examination may reveal signs of acute right ventricular dysfunction, including tachycardia, a low arterial blood pressure, distended neck veins, an accentuated P 2, or a tricuspid regurgitation murmur.[doi.org]
  • Signs that indicate pulmonary hypertension and right ventricular failure include a loud pulmonary component of the second heart sound, right ventricular lift, distended neck veins, and hypotension.[emedicine.medscape.com]
Back Pain
  • Some individuals may also experience uncommon symptoms such as dizziness, back pain or wheezing. Because PE can be fatal, if you experience these signs or symptoms seek medical attention right away.[vascularcures.org]
  • But as the week progressed so did her symptoms — back pain, chest pain, uncontrollable chills — until she could no longer ignore them.[heartinsight.heart.org]
  • These two conditions are usually found in patients with few or no classic symptoms such as coughing (including coughing up blood), chest or upper back pain, acute shortness of breath, or general or specific failure of the circulation that is either cardiac[doi.org]
Panic Attacks
  • The symptoms of pulmonary embolism often occur with, or may mimic other conditions such as heart attack, asthma, pneumonia – even a panic attack. Some people may not have any symptoms at all. This makes it difficult to diagnose.[inogen.com]
Dizziness
  • However, each individual may experience symptoms differently: Sudden shortness of breath (most common) Chest pain, usually worse with breathing A feeling of anxiety A feeling of dizziness, lightheadedness, or fainting Palpitations and heart rarcing Coughing[inovaheart.org]
  • However, each individual may experience pulmonary embolism symptoms differently: sudden shortness of breath (most common) chest pain (usually worse with breathing) a feeling of anxiety a feeling of dizziness, lightheadedness, or fainting palpitations[beaumont.org]
  • The risk of pulmonary embolism increases with age Symptoms include chest pain, dizziness, and rapid breathing The risk of pulmonary embolism is high for individuals who have had a blood clot in the leg or arm In rare cases, a pulmonary embolism can be[medicalnewstoday.com]
  • […] sudden rapid breathing chest pain cough, or coughing up some blood fainting low blood pressure fast or irregular heart beat Other symptoms include: swelling of one or both legs, usually in the calf clammy skin fever and sweating feeling lightheaded or dizzy[healthdirect.gov.au]
  • Some individuals may also experience uncommon symptoms such as dizziness, back pain or wheezing. Because PE can be fatal, if you experience these signs or symptoms seek medical attention right away.[vascularcures.org]
Agitation
  • Hypoxia, which may cause anxiety, restlessness, agitation and impaired consciousness. Pyrexia. Elevated jugular venous pressure. Gallop heart rhythm, a widely split second heart sound, tricuspid regurgitant murmur. Pleural rub.[patient.info]
  • A CNS toxicity phase (agitation evolving to frank seizures or CNS depression) may precede cardiovascular collapse.[doi.org]
  • Recommendations on PFO in the Face of a PE For patients with massive or submassive PE, screening for PFO with an echocardiogram with agitated saline bubble study or transcranial Doppler study for risk stratification may be considered (Class IIb; Level[doi.org]

Workup

The history and clinical examination of a case of pulmonary embolism are usually not sufficient to establish the diagnosis of pulmonary embolism with certainty. Hence, in cases of unexplained respiratory problems, certain investigations must be carried out to reach the final diagnosis [9].

A hypercoaguable workup must be carried out to screen for antithrombin 3 deficiency, protein C or protein S deficiency, connective tissue disorders and homocystinurea.

White blood count, arterial blood gases, D dimer testing, brain natriuretic peptide, serum troponin levels and ischemia modified albumin level are potentially useful laboratory tests that can indicate the presence or absence of pulmonary embolism in the patient.

Imaging techniques that are helpful in confirming the diagnosis of pulmonary embolism include computed tomography angiography, pulmonary angiography, chest radiography, ECG, magnetic resonance imaging (MRI), venography and duplex ultrasonography.

Left Pleural Effusion
  • Echography showed slight increase in left pleural effusion. She had the same diagnosis. The chest pain remained at the same level.[ncbi.nlm.nih.gov]
Normal Chest X-Ray
  • A normal chest X-ray greatly increases the likelihood of a definitive VQ scan result.[clinicaladvisor.com]
Right Axis Deviation
  • Right axis deviation and S 1 Q 3 T 3 pattern were observed in only APE. Low voltage was more frequent in APE and TC. However, the frequencies of these findings were low.[ncbi.nlm.nih.gov]
  • ECG - may be normal, or show any of these changes: sinus tachycardia, atrial fibrillation, nonspecific ST or T-wave abnormalities, right ventricular strain pattern V1-3, right axis deviation, right bundle branch block (RBBB), or deep S-waves in I with[patient.info]
  • The most commonly seen signs in the ECG are sinus tachycardia, right axis deviation, and right bundle branch block. [61] Sinus tachycardia, however, is still only found in 8–69% of people with PE. [62] ECG findings associated with pulmonary emboli may[en.wikipedia.org]
  • Abnormalities reported with acute PE include sinus tachycardia, atrial arrhythmias, low voltage, Q waves in leads III and aVF (pseudoinfarction), S1Q3T3 pattern, Qr pattern in V 1 , P pulmonale, right-axis deviation, ST-segment elevation, ST-segment depression[doi.org]
Thrombocytosis
  • […] trips or hospitalization), pregnancy, use of estrogen-containing hormonal contraceptives, postmenopausal hormones, atrial fibrillation, vascular injury, IV drug abuse, polycythemia vera, heart failure, autoimmune hemolytic anemia, sickle cell anemia, thrombocytosis[medical-dictionary.thefreedictionary.com]
  • […] factors resulting in a hypercoagulable state Acute medical illness Drug abuse (intravenous [IV] drugs) Drug-induced lupus anticoagulant Hemolytic anemias Heparin-associated thrombocytopenia Homocystinemia Homocystinuria Hyperlipidemias Phenothiazines Thrombocytosis[emedicine.medscape.com]
  • […] factors Risk factors for pulmonary embolism also include the following: Drug abuse (intravenous [IV] drugs) Drug-induced lupus anticoagulant Hemolytic anemias Heparin-associated thrombocytopenia Homocystinemia Homocystinuria Hyperlipidemias Phenothiazines Thrombocytosis[emedicine.com]
Hypocapnia
  • Arterial blood gas analysis showed hypoxemia-hypocapnia and D-dimer level was high. Computed tomographic pulmonary angiography (CTPA) demonstrated pulmonary embolism in both main pulmonary arteries, through lobar and segmental branches.[ncbi.nlm.nih.gov]
  • […] evaluate if there are DVTs Studies ECG findings sinus tachycardia atrial fibrillation right ventricular strain S1Q3T3 presence of S wave in lead I and Q wave and inverted T wave in lead III T-wave inversions in V1-V4 Arterial blood gas findings hypoxemia hypocapnia[medbullets.com]
  • Analysis of blood gases reveals arterial hypoxia and hypocapnia. Pulmonary embolism is detected by chest radiographic films, pulmonary angiography, and radioscanning of the lung fields.[medical-dictionary.thefreedictionary.com]
Decreased Oxygen Saturation
  • oxygen saturation (red blood cells that do not have oxygen molecules attached to them) Decreased blood pressure: hypotension (hypo low tension pressure) The condition progresses as follows: The heart rate and respiratory rate may elevate as the body[medicinenet.com]
Incomplete Right Bundle Branch Block
  • right bundle-branch block, anteroseptal ST elevation or depression, or anteroseptal T-wave inversion) Myocardial necrosis is defined as either of the following: —Elevation of troponin I ( 0.4 ng/mL) or —Elevation of troponin T ( 0.1 ng/mL) Low-Risk PE[doi.org]
P Pulmonale
  • P pulmonale, right and left axis deviation, S 1 S 2 S 3 and S 1 Q 3 T 3 patterns, low voltage and clockwise rotation were specific, but not sensitive for APE.[ncbi.nlm.nih.gov]
  • Abnormalities reported with acute PE include sinus tachycardia, atrial arrhythmias, low voltage, Q waves in leads III and aVF (pseudoinfarction), S1Q3T3 pattern, Qr pattern in V 1 , P pulmonale, right-axis deviation, ST-segment elevation, ST-segment depression[doi.org]
Pleural Effusion
  • Echography showed a moderate amount of pleural effusion on both sides and no dilatation of the right cardiac ventricle.[ncbi.nlm.nih.gov]
  • Oligemia (the Westermark sign), prominent central pulmonary artery (the Fleischner sign), pleural-based area of increased opacity (the Hampton hump), vascular redistribution, pleural effusion, elevated diaphragm, and enlarged hilum were also poor predictors[ncbi.nlm.nih.gov]
  • She was found to have left lower lobe consolidation and pleural effusion and was treated as a case of pneumonia. During the hospital course, her respiratory status worsened, and she was intubated on the third hospital day.[ncbi.nlm.nih.gov]
  • In this paper, we will describe an uncommon presentation of lung cancer on a non-smoker middle-aged woman, with recent diagnosis of pulmonary embolism, who develops malignant recurrent pleural effusion, NBTE with cutaneous and neurological manifestations[ncbi.nlm.nih.gov]

Treatment

In patients with suspected deep venous thrombosis or pulmonary embolism, anti-coagulant therapy is initiated immediately [10].

Anticoagulant therapy with heparin administration decreases the mortality rate from 30% to less than 10%. Various anti-coagulation medications include unfractionated heparin, low weight heparin, warfarin, fondaparinux and factor Xa inhibitors.

Thrombolytic agents such as alteplase/reteplase and urokinase/streptokinase are also used in the treatment of pulmonary embolism.

Surgical options for management of pulmonary embolism include:

  • Catheter embolectomy and fragmentation or surgical embolectomy
  • Placement of vena cava filters

Along with these treatment options, supportive care to the patient is ensured.

Prognosis

As far as the common causes of sudden death are concerned, pulmonary embolism is second only to sudden cardiac death.

Up to 10% of the patients who develop pulmonary embolism die within the first hour. Recurrence of pulmonary embolism subsequently causes death in 30% of the patients.

With appropriate anti-coagulant therapy, the mortality rate reduced to less than 5%.

Etiology

More than 90% of the pulmonary emboli result from the dislodging of thrombi from the deep veins of the lower limb. Other less common sites of thrombus formation include prostatic and pelvic veins. Pulmonary emboli usually do not originate in the upper limb except in intravenous drug abusers.

The factors that predispose to venous thrombosis in the lower limbs include the following.

Venous stasis:

Venous trauma:

  • Trauma
  • Intravenous cannulation

Increased coagubility:

Inherited coagulation defects:

Miscellaneous:

  • Smoking [2]

Epidemiology

The per annum incidence of pulmonary embolism in the United States is 1 case per 1000 persons [3]. Although most of these patients are asymptomatic, 60-80% of the patients with DVT develop pulmonary embolism.

In hospitalized patients, pulmonary embolism is the third most common cause of death (up to 650,000 deaths per year). Venous thromboembolism is a major health problem with an incidence of about 250,000 incident cases per year [4] [5].

The incidence of pulmonary embolism and the mortality occurring from it varies from country to country. A research indicates that male sex is more prone to the development of pulmonary embolism with a mortality rate 20-30% higher as compared to females. Pulmonary embolism is much more common in blacks as compared to whites [6].

Sex distribution
Age distribution

Pathophysiology

Pulmonary emboli arise most commonly from the deep veins of the calves. Any factor or disease that cases stasis of blood in the veins can predispose to the formation of thrombi. Dislodged thrombi reach the lung after traveling through the right side of the heart.

Large emboli occlude the proximal arteries and the right ventricular outflow, causing a rapid decrease in the the cardiac output and leading to right ventricular failure. The prominent features are those of vascular collapse e.g. hypotension and syncope.

On the other hand, small and medium sized emboli occlude the segmental arteries causing infarction of the lung segment involved. It manifests as pleural chest pain and hemoptysis.

In contrast, multiple micro-emboli occlude the capillary beds of the lungs. Due to collateral vascular supply, there is no pulmonary infarction  but there insidious loss of the microvascular bed supplying the gas exchange units of the lungs leading to pulmonary hypertension and right ventricular failure.

Prevention

Prevention of the development of venous thromboembolism can effectively reduce the likelihood of the development of pulmonary embolism. This is done by the following measures:

Avoid venous stasis:

Venous stasis during surgery can be avoided by stimulation of the calf muscles. Following surgery, early mobilization and leg exercises are helpful in reducing the likelihood of venous thromboembolism.

Use of anticoagulants in susceptible individuals:

Anticoagulants such as warfarin and heparin are used in the patients who are at high risk for developing thromboembolism.

Summary

Pulmonary emboli are thrombi that dislodge into the lungs usually from the deep veins of the lower limbs. Less common sites of thrombus formation include the veins of the pelvis, prostate and the upper limbs.

Pulmonary emboli may be small, medium or large. Each of these cause respiratory and hemodynamic compromise by different mechanisms. Hence, pulmonary embolism is not a disease; rather it is the complication of deep venous thrombosis (DVT).

It is a life threatening emergency and needs to be diagnosed and treated promptly.

Patient Information

Pulmonary embolism refers to the state in which masses of clotted blood that form in the lower limbs dislodge into the lungs. Males are more prone to the development of this complication.

Smoking, obesity, decreased physical activity and intake of unbalanced diet make the person more prone to the development of pulmonary embolism. It is a very dangerous condition and the patient needs to be hospitalized immediately. High risk patients must be identified and preventive measures must be carried out.

References

Article

  1. Malek J, Rogers R, Kufera J, Hirshon JM. Venous thromboembolic disease in the HIV-infected patient. The American journal of emergency medicine. Mar 2011;29(3):278-282.
  2. Stein PD, Beemath A, Matta F, et al. Clinical characteristics of patients with acute pulmonary embolism: data from PIOPED II. The American journal of medicine. Oct 2007;120(10):871-879.
  3. Horlander KT, Mannino DM, Leeper KV. Pulmonary embolism mortality in the United States, 1979-1998: an analysis using multiple-cause mortality data. Archives of internal medicine. Jul 28 2003;163(14):1711-1717.
  4. Heit JA. The epidemiology of venous thromboembolism in the community: implications for prevention and management. Journal of thrombosis and thrombolysis. Feb 2006;21(1):23-29.
  5. Silverstein MD, Heit JA, Mohr DN, Petterson TM, O'Fallon WM, Melton LJ, 3rd. Trends in the incidence of deep vein thrombosis and pulmonary embolism: a 25-year population-based study. Archives of internal medicine. Mar 23 1998;158(6):585-593.
  6. Schneider D, Lilienfeld DE, Im W. The epidemiology of pulmonary embolism: racial contrasts in incidence and in-hospital case fatality. Journal of the National Medical Association. Dec 2006;98(12):1967-1972.
  7. Worsley DF, Alavi A. Comprehensive analysis of the results of the PIOPED Study. Prospective Investigation of Pulmonary Embolism Diagnosis Study. Journal of nuclear medicine : official publication, Society of Nuclear Medicine. Dec 1995;36(12):2380-2387.
  8. Carrascosa MF, Batan AM, Novo MF. Delirium and pulmonary embolism in the elderly. Mayo Clinic proceedings. 2009;84(1):91-92.
  9. Torbicki A, Perrier A, Konstantinides S, et al. Guidelines on the Diagnosis and Management of Acute Pulmonary Embolism The Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC). Revista espanola de cardiologia. 2008;61(12):1330.
  10. Kearon C, Kahn SR, Agnelli G, et al. Antithrombotic therapy for venous thromboembolic disease: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th Edition). Chest. Jun 2008;133(6 Suppl):454S-545S.

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Last updated: 2018-06-22 05:55