Pharmacotherapy Case Study: Pulmonary Embolism (PE) by Dr. Nehad Jaser

Patient Profile: 55-year-old female

Chief Complaint: “I can’t breathe, and my chest hurts when I take a deep breath. It started suddenly this morning.”
History of Present Illness:
- Sudden-onset dyspnea at rest, worsening over 6 hours.
- Sharp, pleuritic chest pain radiating to the back, exacerbated by deep breathing.
- One episode of hemoptysis (blood-tinged sputum).
- Denies leg swelling, recent trauma, or prolonged immobility.
Medical History:
- Recent left total hip replacement surgery 2 weeks ago.
- Obesity (BMI 32 kg/m²), hypertension.
- No prior history of DVT/PE or cancer.
Medications:
- Enoxaparin 40 mg SC daily (post-op prophylaxis discontinued 5 days ago).
- Acetaminophen PRN for pain.
Social History:
- Sedentary recovery post-surgery; limited ambulation.
- Nonsmoker, no alcohol use.

Vitals:
- BP: 110/70 mmHg, HR: 120 bpm (sinus tachycardia), RR: 28/min, SpO₂: 88% on room air (improves to 94% with 4 L/min O₂).
- Temp: 98.9°F, BMI: 32 kg/m².
Physical Exam:
- Respiratory: Tachypnea, diminished breath sounds at right lung base.
- Cardiovascular: Loud P2 heart sound, no jugular venous distension.
- Extremities: No edema or erythema; negative Homan’s sign.
Diagnostic Studies:
- CT Pulmonary Angiography (CTPA): Right main pulmonary artery filling defect (acute PE).
- Echocardiogram: Right ventricular dilation (RV/LV ratio >1.0), mild systolic dysfunction.
- Labs:
  - D-dimer: 3,500 ng/mL (elevated).
  - Troponin: 0.08 ng/mL (mildly elevated), BNP: 300 pg/mL.
  - CrCl: 75 mL/min (Cockcroft-Gault).

Primary Diagnosis:
- Acute Pulmonary Embolism (submassive, intermediate-risk PE based on RV strain).
Risk Stratification:
- PESI Class III (age >50, tachycardia, hypoxemia).
- Simplified PE Severity Index (sPESI): 1 point (HR >110 bpm).
Etiology:
- Likely provoked by post-surgical immobility and discontinuation of prophylactic enoxaparin.

Anticoagulation:
- Therapeutic Enoxaparin: 1 mg/kg SC every 12 hours (bridge to oral therapy).
- Transition to DOAC: Apixaban 10 mg twice daily ×7 days, then 5 mg twice daily (preferred for CrCl ≥25 mL/min).
Hemodynamic Support:
- Oxygen therapy (maintain SpO₂ >92%).
- IV fluids cautiously (avoid RV overload).
Advanced Therapy (if decompensates):
- Systemic Thrombolysis: Alteplase 10 mg IV bolus, then 90 mg infusion over 2 hours (reserved for hemodynamic instability).

Anticoagulation Duration:
- Minimum 3 months (provoked PE post-surgery). Consider extended therapy if unprovoked.
Secondary Prevention:
- Gradual ambulation with compression stockings.
- Weight loss counseling (reduce obesity-related thrombotic risk).

Immediate:
- Continuous telemetry for arrhythmias (e.g., atrial fibrillation).
- Serial troponin/BNP to assess RV strain.
Follow-Up:
- 48-hour echocardiogram to reassess RV function.
- Weekly: Renal function, hemoglobin (monitor for bleeding).
- 3-month CTPA if persistent symptoms.

Adherence: Stress uninterrupted anticoagulation; missing doses increases clot risk.
Bleeding Signs: Report melena, hematuria, or severe headaches.
Lifestyle: Avoid prolonged sitting; ambulate hourly during travel.

Enoxaparin + Apixaban: Rapid anticoagulation reduces clot propagation; DOACs offer convenience and lower bleeding risk vs. warfarin.
Avoid Thrombolytics: Reserved for high-risk PE due to bleeding risks; this patient’s stable RV strain favors anticoagulation alone.
Oxygen/Fluids: Supportive care mitigates hypoxemia and RV failure without exacerbating volume overload.

1 week: Assess adherence, dyspnea, and bleeding risk.
3 months: Re-evaluate anticoagulation duration; consider thrombophilia testing if unprovoked.
6 months: Repeat echocardiogram if persistent RV dysfunction.

This structured approach balances acute stabilization, secondary prevention, and patient-specific factors to optimize outcomes in PE management.

د. نهاد جاسرDr. Nehad Jaser