Pulmonary embolism differential diagnosis

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Resident Survival Guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] The APEX Trial Investigators; Associate Editor(s)-in-Chief: Rim Halaby, M.D. [2]

Overview

Pulmonary embolism must be distinguished from other life-threatening causes of chest pain including acute myocardial infarction, aortic dissection, and pericardial tamponade, as well as a large list of non-life-threatening causes of chest discomfort and shortness of breath.

Differential Diagnosis

Differential Diagnosis Based on Symptoms

Pulmonary embolism (PE) should be differentiated from other diseases presenting with chest pain, shortness of breath and tachypnea. The differentials include the following:

Diseases	Diagnostic tests			Physical Examination			Symptoms							Past medical history	Other Findings
	CT scan and MRI	EKG	Chest X-ray	Tachypnea	Tachycardia	Fever	Chest Pain	Hemoptysis	Dyspnea on Exertion	Wheezing	Chest Tenderness	Nasalopharyngeal Ulceration	Carotid Bruit
Pulmonary embolism	On CT angiography: Intra-luminal filling defect On MRI: Narrowing of involved vessel No contrast seen distal to obstruction Polo-mint sign (partial filling defect surrounded by contrast)	S1Q3T3 pattern representing acute right heart strain	Fleischner sign (enlarged pulmonary artery), Hampton hump, Westermark's sign	✔	✔	✔ (Low grade)	✔	✔ (In case of massive PE)	✔	-	-	-	-	Hypercoagulating conditions (Factor V Leiden, thrombophilia, deep vein thrombosis, immobilization, malignancy, pregnancy)	May be associated with metabolic alkalosis and syncope
Congestive heart failure	On CT scan: Mediastinal lymphadenopathy Hazy mediastinal fat On MRI: Abnormality of cardiac chambers (hypertrophy, dilation) Delayed enhancement MRI may help characterize the myocardial tissue (fibrosis) Late enhancement of contrast in conditions such as myocarditis, sarcoidosis, amyloidosis, Anderson-Fabry's disease, Chagas disease)	Goldberg's criteria may aid in diagnosis of left ventricular dysfunction: (High specificity) SV1 or SV2 + RV5 or RV6 ≥3.5 mV Total QRS amplitude in each of the limb leads ≤0.8 mV R/S ratio <1 in lead V4	Cardiomegaly	✔	✔	✔	-	-	✔	-	-	-	-	Previous myocardial infarction Hypertension (systemic and pulmonary) Cardiac arrythmias Viral infections (myocarditis) Congenital heart defects	Right heart failure associated with: Hepatomegaly Positive hepato-jugular reflex Increased jugular venous pressure Peripheral edema Left heart failure associated with: Pulmonary edema Eventual right heart failure
Percarditis	On contrast enhanced CT scan: Enhancement of the pericardium (due to inflammation) Pericardial effusion Pericardial calcification On gadolinium-enhanced fat-saturated T1-weighted MRI: Pericardial enhancement (due to inflammation) Pericardial effusion	ST elevation PR depression	Large collection of fluid inside the pericardial sac (pericardial effusion) Calcification of pericardial sac	✔	✔	✔ (Low grade)	✔ (Relieved by sitting up and leaning forward)	-	✔	-	-	-	-	Infections: Viral (Coxsackie virus, Herpes virus, Mumps virus, HIV) Bacteria (Mycobacterium tuberculosis-common in developing countries) Fungal (Histoplasmosis) Idiopathic in a large number of cases Autoimmune Uremia Malignancy Previous myocardial infarction	May be clinically classified into: Acute (< 6 weeks) Sub-acute (6 weeks - 6 months) Chronic (> 6 months)
Pneumonia	On CT scan: (not generally indicated) Consolidation (alveolar/lobar pneumonia) Peribronchial nodules (bronchopneumonia) Ground-glass opacity (GGO) Abscess Pleural effusion On MRI: Not indicated	Prolonged PR interval Transient T wave inversions	Consolidation (alveolar/lobar pneumonia) Peribronchial nodules (bronchopneumonia) Ground-glass opacity (GGO)	✔	✔	✔	✔	-	✔	✔	-	-	-	Ill-contact Travelling Smoking Diabetic Recent hospitalization Chronic obstructive pulmonary disease	Requires sputum stain and culture for diagnosis Empiric management usually started before culture results
Vasculitis	On CT scan: (Takayasu arteritis) Vessel wall thickening Luminal narrowing of pulmonary artery Masses or nodules (ANCA-associated granulomatous vasculitis) On MRI: Homogeneous, circumferential vessel wall swelling	Right or left bundle-branch block (Churg-Strauss syndrome) Atrial fibrillation (Churg-Strauss syndrome) Non-specific ST segment and T wave changes	Nodules Cavitation	✔	✔	✔	✔	✔	✔	-	✔	✔	✔	Takayasu arteritis usually found in persons aged 4-60 years with a mean of 30 Giant-cell arteritis usually occurrs in persons aged > 60 years Churg-Strauss syndrome may present with asthma, sinusitis, transient pulmonary infiltrates and neuropathy alongwith cardiac involvement Granulomatous vasculitides may present with nephritis and upper airway (nasopharyngeal) destruction
Chronic obstructive pulmonary disease (COPD)	On CT scan: Chronic bronchitis may show bronchial wall thickening, scarring with bronchovascular irregularity, fibrosis Emphysema may show alveolar septal destruction and airspace enlargement (Centrilobular- upper lobe, panlobular- lower lobe) Giant bubbles On MRI: Increased diameter of pulmonary arteries Peripheral pulmonary vasculature attentuation Loss of retrosternal airspace due to right ventricular enlargement Hyperpolarized Helium MRI may show progressively poor ventilation and destruction of lung	Multifocal atrial tachycardia (atleast 3 distinct P wave morphologies)	Enlarged lung shadows (emphysema) Flattening of diaphragm (emphysema)	✔	✔	-	-	-	✔	✔	-	-	-	Smoking Alpha-1 antitrypsin deficiency Increased sputum production (chronic bronchitis) Cough	Alpha 1 antitrypsin deficiency may be associated with hepatomegaly

Life Threatening Differential Diagnosis

• Acute myocardial infarction
• Aortic dissection
• Pericardial tamponade

Common Differential Diagnosis in Outpatients

Among outpatients presenting with dyspnea, <4 % are diagnosed with PE. Common differential diagnoses include:

• Acute heart failure
• Pneumonia
• Chronic obstructive pulmonary disease exacerbation

Complete List of Differential Diagnosis

• Acute coronary syndrome
• Acute heart failure
• Asthma acute exacerbation
• Acute respiratory distress syndrome
• Anemia
• Angina pectoris
• Anxiety disorders
• Aortic stenosis
• Atrial fibrillation (diagnosis and management)
• Bronchitis
• Cardiogenic shock
• Cardiac tamponade
• Chronic obstructive pulmonary disease exacerbation
• Community acquired pneumonia
• Cor pulmonale
• Costochondritis
• Dilated cardiomyopathy
• Distributive shock
• Emphysema
• Fat embolism
• Hemorrhagic shock
• Herpes zoster
• Hyperventilation
• Mediastinitis
• Mitral stenosis
• Musculoskeletal pain
• Myocardial infarction
• Myocardial ischemia
• Myocarditis
• Noncardiogenic pulmonary edema
• Pericarditis
• Pleuritis
• Pneumonia
• Pneumothorax
• Pulmonary hypertension, primary
• Pulmonary hypertension, secondary
• Restrictive cardiomyopathy
• Rib fracture
• Salicylate intoxication
• Septic shock
• Silicone pulmonary embolism
• Sudden cardiac death
• Superior vena cava syndrome
• Syncope
• Toxic shock syndrome
• Trauma to the chest
• Unstable angina

References