Origins
A 50-year-old male chronic smoker with uncontrolled hypertension and hyperlipidemia presents with sudden-onset dyspnea. He is diagnosed with a pulmonary embolism. Which component of Virchow’s triad is most directly influenced by his smoking history?
A) Venous stasis
B) Endothelial injury
C) Hypercoagulability
D) Increased cardiac output
E) Decreased fibrinogen levels
B) Endothelial injury
Smoking damages the vascular endothelium, leading to increased clot formation.
endothelial dysfunction → disrupts laminar blood flow and promotes clot formation
A 55-year-old woman presents with sudden-onset pleuritic chest pain, hemoptysis, and shortness of breath. She has a history of recent orthopedic surgery. Arterial blood gas shows pH 7.48, PaO₂ 75 mmHg, and PaCO₂ 28 mmHg. What is the most likely explanation for the patient's acid-base disturbance?
A) Increased metabolic acid production
B) Decreased renal bicarbonate reabsorption
C) Hyperventilation due to hypoxemia
D) Respiratory muscle fatigue
E) Lactic acidosis from obstructive shock
C) Hyperventilation due to hypoxemia
A 50-year-old man with a history of deep vein thrombosis (DVT) presents with sudden-onset shortness of breath and pleuritic chest pain. He is also experiencing tachycardia and tachypnea. Which of the following findings on physical examination would most likely indicate a pulmonary embolism?
A. Bilateral crackles
B. Jugular venous distension
C. Decreased breath sounds
D. Pleural friction rub
E. Cyanosis
D. Pleural friction rub
A pleural friction rub may be heard in patients with a pulmonary embolism when there is inflammation and irritation of the pleural lining. This is particularly common with peripheral emboli. The other findings, while they may be present, are less specific to PE.
A 55-year-old man presents with sudden-onset dyspnea and pleuritic chest pain. His Wells score is 5. What is the next best step in management?
A) D-dimer testing
B) CT pulmonary angiogram
C) Echocardiogram
D) Bedside ultrasound
E) Chest X-ray
B) CT pulmonary angiogram
A Wells score >3 indicates a high probability of PE, so definitive imaging is required.
A 55-year-old woman presents to the emergency department with sudden-onset shortness of breath, chest pain, and hemoptysis. A computed tomography (CT) scan of the chest reveals a large pulmonary embolism in the right main pulmonary artery. The patient is treated with tissue-type plasminogen activator (tPA). Which of the following best describes the mechanism of action of tPA?
A. Inhibits platelet aggregation
B. Converts plasminogen to plasmin
C. Activates antithrombin III
D. Inhibits thrombin
E. Activates protein C
B. Converts plasminogen to plasmin
tPA works by converting plasminogen to plasmin, an enzyme that breaks down fibrin clots, thus helping to dissolve the pulmonary embolism.
A 58-year-old man with a history of hypertension and obesity presents to the emergency department with sudden-onset dyspnea and pleuritic chest pain. He recently underwent total knee replacement surgery and has been mostly bedridden for the past week. His vital signs show tachycardia and mild hypoxia. A CT pulmonary angiography confirms the presence of a pulmonary embolism in the segmental branches of the pulmonary artery. Which of the following is the most likely location of the emboli?
A) Right upper lobe
B) Left upper lobe
C) Bilateral lower lobes
D) Right middle lobe
E) Lingula
C) Bilateral lower lobes
Pulmonary emboli most commonly lodge in the lower lung lobes due to higher perfusion in these regions from gravity.
A 63-year-old man with a history of deep vein thrombosis suddenly develops dyspnea and chest pain. Echocardiography reveals right ventricular dilation and bowing of the interventricular septum into the left ventricle. What is the most likely cause of these findings?
A) Decreased left ventricular compliance
B) Decreased pulmonary vascular resistance
C) Increased right ventricular afterload
D) Increased cardiac output
E) Left ventricular hypertrophy
C) Increased right ventricular afterload
A 53-year-old man presents with sudden-onset shortness of breath, chest pain, and light-headedness. He has a history of recent surgery and prolonged bed rest. On examination, his blood pressure is 85/60 mmHg, and he appears diaphoretic. Which of the following physical findings would most strongly suggest a pulmonary embolism?
A. Bilateral leg edema
B. Hepatomegaly
C. Unilateral leg swelling and tenderness
D. Diffuse abdominal pain
E. Bilateral wheezing
C. Unilateral leg swelling and tenderness
Unilateral leg swelling and tenderness are indicative of deep vein thrombosis (DVT), which is a common precursor to pulmonary embolism. The patient's recent surgery and bed rest further increase the risk of DVT and subsequent PE.
A 45-year-old woman presents with unilateral leg swelling and pain after a long flight. Bedside ultrasound confirms the presence of a DVT. What is the most appropriate next step?
A) Start low molecular weight heparin
B) Order a CT pulmonary angiogram
C) Obtain a D-dimer test
D) Observe and repeat ultrasound in 48 hours
E) Perform an echocardiogram
A) Start low molecular weight heparin
A diagnosed DVT warrants anticoagulation to prevent PE.
A 60-year-old man with a history of deep vein thrombosis (DVT) presents to the emergency department with sudden-onset shortness of breath and pleuritic chest pain. A CT pulmonary angiography confirms the diagnosis of pulmonary embolism (PE). Which of the following best explains the importance of anticoagulant therapy in the management of this condition?
A. It reduces the risk of recurrent venous thromboembolism.
B. It directly dissolves the thrombus in the pulmonary artery.
C. It alleviates hypoxemia and improves oxygenation.
D. It decreases the pulmonary artery pressure immediately.
E. It provides analgesic relief for pleuritic chest pain.
A. It reduces the risk of recurrent venous thromboembolism.
Prevents further clot formation and reduces the risk of recurrent venous thromboembolism. This helps in stabilizing the patient's condition and preventing additional complications.
A 65-year-old man with a history of atrial fibrillation and recent hip replacement presents with sudden-onset dyspnea, pleuritic chest pain, and hemoptysis. Vital signs show tachycardia and hypoxia. A CT pulmonary angiography reveals a filling defect in the left pulmonary artery. Which of the following is the most likely source of the embolus?
A) Left atrial appendage
B) Common carotid artery
C) Deep veins of the lower extremity
D) Right ventricle
E) Superficial femoral vein
C) Deep veins of the lower extremity
Most pulmonary emboli originate from proximal deep veins of the lower extremities, specifically the iliac, femoral, and popliteal veins. These deep vein thromboses (DVTs) can dislodge and travel to the pulmonary arteries, causing a PE.
A 40-year-old woman presents to the emergency department with shortness of breath and chest pain. She has a history of recent long-haul travel. Pulmonary artery catheterization shows a mean pulmonary artery pressure of 45 mmHg (norm: 30-40 mmHg). What is the best explanation for this finding?
A) Chronic pulmonary hypertension due to left heart disease
B) Increased pulmonary vascular resistance due to embolic obstruction
C) Hypoxic vasoconstriction from chronic lung disease
D) Increased left atrial pressure due to mitral stenosis
E) Hyperdynamic circulation due to sepsis
B) Increased pulmonary vascular resistance due to embolic obstruction
A 39-year-old woman with a history of deep vein thrombosis presents with sudden-onset dyspnea, pleuritic chest pain, and a rapid heart rate. On physical examination, she has jugular venous distension and a right ventricular heave. What is the underlying mechanism causing her tachypnea?
A. Increased alveolar ventilation
B. Decreased perfusion leading to hypoxia and CO2 buildup
C. Inflammatory response in the pleura
D. Activation of pain receptors in the chest
E. Stimulation of the parasympathetic nervous system
B. Decreased perfusion leading to hypoxia and CO2 buildup
The decreased perfusion caused by the pulmonary embolism leads to hypoxia and a buildup of CO2. This triggers a physiologic response to increase the rate of breathing (tachypnea) in an attempt to correct the CO2 imbalance.
A 60-year-old man presents with shortness of breath and tachycardia. His ECG reveals an S1Q3T3 pattern. What is the likely diagnosis?
A) Myocardial infarction
B) Pericarditis
C) Atrial fibrillation
D) Pulmonary embolism
E) Pneumothorax
D) Pulmonary embolism
S1Q3T3 is a classic but nonspecific ECG finding for PE.
A 72-year-old woman presents to the emergency department with sudden-onset shortness of breath, chest pain, and syncope. On examination, her blood pressure is 85/50 mmHg, heart rate is 120 beats per minute, and respiratory rate is 30 breaths per minute. Which of the following findings would best indicate that this patient is hemodynamically unstable due to a pulmonary embolism?
A. Respiratory rate > 20 breaths per minute
B. Heart rate > 100 beats per minute
C. Blood pressure < 90 mmHg systolic for over 15 minutes
D. Oxygen saturation < 90%
E. Jugular venous distention
C. Blood pressure < 90 mmHg systolic for over 15 minutes
A systolic blood pressure less than 90 mmHg for over 15 minutes is a key indicator of hemodynamic instability in a patient with a pulmonary embolism. This finding suggests significant cardiovascular compromise, requiring immediate intervention.
A 32-year-old woman in her third trimester of pregnancy suddenly develops respiratory distress, hypotension, and altered mental status during labor. She has no history of deep vein thrombosis. Which of the following is the most likely type of embolism in this patient?
A) Fat embolism
B) Air embolism
C) Amniotic fluid embolism
D) Bacterial embolism
E) Tumor embolism
C) Amniotic fluid embolism
Amniotic fluid embolism (AFE) is a rare but life-threatening complication of pregnancy that occurs when amniotic fluid enters the maternal circulation during labor, delivery, or postpartum.
A 50-year-old man is diagnosed with a massive pulmonary embolism. Which of the following physiological changes is most likely responsible for his systemic hypotension?
A) Increased left ventricular preload
B) Decreased right ventricular afterload
C) Reduced left ventricular filling
D) Increased pulmonary venous return
E) Increased cardiac contractility
C) Reduced left ventricular filling
A 48-year-old man presents to the clinic with complaints of sudden-onset shortness of breath, sharp chest pain that worsens with deep breaths, and a rapid heart rate. He has no significant past medical history but reports that he has been sedentary due to a recent job change. His pulse is 125 beats per minute, and his respiratory rate is 30 breaths per minute. Physical examination reveals jugular venous distension and a right ventricular heave. What is the most likely cause of his symptoms?
A. Acute coronary syndrome
B. Pulmonary embolism
C. Pericarditis
D. Chronic obstructive pulmonary disease (COPD)
E. Pleural effusion
B. Pulmonary embolism
The patient's sudden-onset dyspnea, pleuritic chest pain, tachycardia, tachypnea, jugular venous distension, and right ventricular heave are indicative of pulmonary embolism. His sedentary lifestyle due to a recent job change is a risk factor for DVT, which can lead to PE.
A 70-year-old woman with recent surgery presents with mild dyspnea. Her Wells score is 0. What is the most appropriate next step?
A) Order a CT pulmonary angiogram
B) Perform a bedside ultrasound
C) Obtain a D-dimer test
D) Start empiric anticoagulation
E) Perform a ventilation-perfusion scan
C) Obtain a D-dimer test
A low Wells score means D-dimer can be used to rule out PE.
A 62-year-old man presents to the emergency department with sudden-onset severe shortness of breath, pleuritic chest pain, and hypotension (systolic BP 80/50 mmHg). A bedside echocardiogram reveals a large pulmonary embolism (PE) in the right pulmonary artery. Despite administration of vasopressors and oxygen, the patient remains hemodynamically unstable and thrombolytic therapy is contraindicated due to a recent major surgery. Which of the following is the most appropriate embolectomy procedure for this patient?
A. High-frequency ultrasound-assisted embolectomy
B. Peripheral artery bypass graft
C. Coronary artery stent placement
D. Endovascular coiling
E. Surgical pulmonary embolectomy
E. Surgical pulmonary embolectomy
Surgical pulmonary embolectomy is an appropriate procedure for patients with a large PE who remain hemodynamically unstable and have contraindications to thrombolytic therapy. It involves the surgical removal of the embolus from the pulmonary arteries to restore perfusion and improve hemodynamics.
A 72-year-old bedridden patient develops sudden dyspnea, pleuritic chest pain, and tachycardia. A ventilation-perfusion scan shows multiple segmental mismatched defects. Which of the following is the most likely pathophysiological consequence of this condition?
A) Decreased pulmonary vascular resistance
B) Increased pulmonary compliance
C) Increased alveolar dead space
D) Decreased arterial oxygen saturation with normal A-a gradient
E) Increased perfusion of affected lung regions
C) Increased alveolar dead space
PE blocks blood flow to certain areas of the lung, leading to ventilation without perfusion. This increases alveolar dead space because the affected alveoli receive oxygen but no blood flow, leading to impaired gas exchange and eventual hypoxemia.
A 67-year-old woman presents with dyspnea and pleuritic chest pain. Imaging confirms a pulmonary embolism. Which of the following mediators is most responsible for worsening pulmonary perfusion by promoting platelet aggregation and vasoconstriction?
A) Histamine
B) Serotonin
C) Bradykinin
D) Prostacyclin
E) Nitric oxide
B) Serotonin
A 40-year-old woman presents to the emergency department with sudden-onset dyspnea, pleuritic chest pain, and hemoptysis. She has a history of recent prolonged bed rest following a leg injury. On physical examination, her heart rate is 120 beats per minute, and her respiratory rate is 28 breaths per minute. Which of the following combinations of symptoms is most consistent with a pulmonary embolism?
A. Sudden-onset dyspnea, sharp pleuritic chest pain, hemoptysis
B. Gradual onset of shortness of breath, dull chest pain, productive cough
C. Intermittent shortness of breath, substernal chest pain, orthopnea
D. Chronic cough, wheezing, night sweats
E. Gradual onset of fatigue, weight loss, persistent cough
A. Sudden-onset dyspnea, sharp pleuritic chest pain, hemoptysis
A 30-year-old pregnant woman with suspected PE cannot undergo CT pulmonary angiography due to the risks associated with contrast dye. What is the next best imaging modality?
A) Chest X-ray
B) Ventilation-perfusion (V/Q) scan
C) Bedside ultrasound
D) Echocardiogram
E) Pulmonary artery catheterization
B) Ventilation-perfusion (V/Q) scan
A V/Q scan is the preferred alternative when CTPA is contraindicated.
A 68-year-old woman presents to the emergency department with sudden-onset severe shortness of breath, chest pain, and hypotension (systolic BP 85/45 mmHg for over 15 minutes). She appears diaphoretic and is in acute distress. Bedside echocardiogram shows evidence of a large pulmonary embolism (PE). Due to a recent major surgery, the patient is not eligible for thrombolytic therapy. What is the most appropriate next step in management?
A. Perform CT pulmonary angiography first, then consider anticoagulation
B. Initiate empiric anticoagulation with tissue-type plasminogen activator immediately
C. Administer vasopressors and oxygen, perform portable perfusion scan or bedside echocardiogram, then start anticoagulation
D. Administer alteplase immediately
E. Place an inferior vena cava (IVC) filter
C. Administer vasopressors and oxygen, perform portable perfusion scan or bedside echocardiogram, then start anticoagulation
This approach ensures the patient’s hemodynamic stability and confirms the diagnosis before proceeding with anticoagulation, given the contraindication for thrombolytic therapy.