Emergency Medicine · Year 3 · from Emergency Medicine

Case 1: Massive Pulmonary Embolism

Patient Demographics

  • Age: 42 years
  • Sex: Female
  • Occupation: Accountant

Chief Complaint

"I suddenly can't breathe and I feel like I'm going to die."

History of Present Illness

A 42-year-old female presents with acute onset of severe dyspnea that began 30 minutes ago while at her desk at work. She describes sudden shortness of breath, chest tightness, and a feeling of impending doom. She had a 10-hour flight from Europe 5 days ago and has been on oral contraceptives for 15 years. She denies cough, hemoptysis, fever, or leg pain/swelling.

Initial Assessment

ESI Level: 1 - Hemodynamically unstable

Vital Signs:

  • Heart rate: 128 bpm
  • Blood pressure: 78/52 mmHg
  • Respiratory rate: 32 breaths/min
  • SpO2: 82% on room air
  • Temperature: 37.1C

First Impression:

  • Acutely distressed, tripod positioning
  • Cyanotic lips
  • Diaphoretic
  • Speaks in single words

Physical Examination

Cardiovascular:

  • Tachycardic, regular rhythm
  • Loud P2 (pulmonic component)
  • JVD present
  • Cool extremities

Pulmonary:

  • Tachypneic with accessory muscle use
  • Clear breath sounds bilaterally
  • No wheezes, crackles, or rhonchi

Extremities:

  • Left calf mildly swollen
  • No cord palpable
  • Negative Homan's sign (unreliable)

Clinical Decision Rules

Wells Score for PE:

  • Clinical signs of DVT: +3
  • PE most likely diagnosis: +3
  • Heart rate >100: +1.5
  • Immobilization/surgery: 0
  • Previous DVT/PE: 0
  • Hemoptysis: 0
  • Malignancy: 0
  • Total: 7.5 (High probability)

Note: PERC rule not applicable - high clinical probability

Diagnostic Evaluation

ECG:

  • Sinus tachycardia at 128 bpm
  • S1Q3T3 pattern (classic but not sensitive)
  • Right axis deviation
  • Right ventricular strain pattern (T-wave inversions V1-V4)

ABG (on 15L non-rebreather):

  • pH: 7.48
  • pCO2: 28 mmHg
  • pO2: 58 mmHg
  • HCO3: 22 mEq/L
  • A-a gradient: 55 (markedly elevated)

Bedside Echocardiography:

  • Right ventricular dilation (RV:LV >1:1)
  • Septal flattening ("D-sign")
  • McConnell's sign (RV free wall akinesis with apical sparing)
  • Moderate tricuspid regurgitation
  • Estimated RVSP: 55 mmHg

CT Pulmonary Angiography:

  • Saddle embolus at main pulmonary artery bifurcation
  • Additional emboli in bilateral lower lobe arteries
  • RV/LV ratio 1.4 (RV strain)

Diagnosis

Massive (High-Risk) Pulmonary Embolism with:

  • Hemodynamic instability (SBP <90)
  • Right ventricular dysfunction
  • Evidence of DVT (provoked by OCP + long-haul flight)

Management

Risk Stratification:

  • Massive PE (hemodynamic instability) = highest risk
  • Thrombolysis indicated

Immediate Treatment:

  1. High-flow oxygen via non-rebreather
  2. IV access x2, fluid bolus 500mL (cautiously)
  3. Unfractionated heparin bolus 80 units/kg
  4. Vasopressor support with norepinephrine

Systemic Thrombolysis:

  • Alteplase 100mg IV over 2 hours
  • BP improved to 102/68 after 30 minutes
  • SpO2 improved to 94% on 6L NC

Post-Thrombolysis:

  • Heparin infusion restarted (no bolus)
  • Transitioned to DOAC (rivaroxaban) after 5 days
  • OCP discontinued permanently

Hospital Course

Repeat Echo (48 hours):

  • Normalized RV size and function
  • RVSP: 35 mmHg

Lower Extremity Ultrasound:

  • Acute DVT in left popliteal vein

Discharge:

  • Rivaroxaban 15mg BID x21 days, then 20mg daily
  • Duration: Minimum 3 months, consider extended given provoked PE
  • Hypercoagulability workup as outpatient

Teaching Points

  1. Hypoxia out of proportion to exam: Clear lungs with severe hypoxemia = think PE
  2. Massive PE = thrombolysis: Hemodynamic instability is the indication
  3. Bedside echo for risk stratification: RV dysfunction guides treatment urgency
  4. CT-PA is gold standard: But don't delay treatment in unstable patients
  5. Anticoagulation timing: Start heparin BEFORE CT if high clinical suspicion

Clinical Image

Image Description: CT pulmonary angiography demonstrating a large saddle pulmonary embolus at the bifurcation of the main pulmonary artery with extension into bilateral pulmonary arteries.

Attribution: Image from Radiopaedia.org, Case courtesy of Dr. Matt Skalski. Licensed under CC BY-NC-SA 3.0. Source: https://radiopaedia.org/cases/saddle-pulmonary-embolism

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