Key Points
- Stabilize ABCs; begin targeted evaluation without delaying life-saving therapy.
- Use system-specific risk tools to guide testing and disposition.
- Order high-yield tests first; escalate imaging when indicated.
- Start evidence-based initial therapy and reassess frequently.
Algorithm
- Primary survey and vitals; IV access and monitors.
- Focused history/physical; identify red flags and likely etiologies.
- Order system-appropriate labs and imaging (see Investigations).
- Initiate guideline-based empiric therapy (see Pharmacology).
- Reassess response; arrange consultation and definitive management.
Clinical Synopsis & Reasoning
PE spans from incidental subsegmental disease to obstructive shock. Evaluate pretest probability (e.g., Wells/Geneva), apply age‑adjusted D‑dimer when appropriate, and use CTPA or V/Q based on renal function, pregnancy, and contrast tolerance. Risk‑stratify by RV dysfunction (echo/CT), biomarkers (troponin/BNP), and clinical instability to anticipate decompensation.
Treatment Strategy & Disposition
Anticoagulate promptly when suspicion is high and bleeding risk acceptable; choose DOACs for most stable patients, LMWH in cancer, and UFH if thrombolysis or procedures are possible. Consider systemic thrombolysis or catheter‑directed therapy for massive/submassive PE with deterioration. Assess for precipitating factors and plan duration of therapy (provoked 3 mo; unprovoked often extended). ICU for shock or advanced support; otherwise ward or outpatient pathways for low‑risk cases with reliable follow‑up.
Epidemiology / Risk Factors
- Atherosclerotic risk (HTN, DM, HLD, smoking)
- Age/family history of premature CAD
Investigations
| Test | Role / Rationale | Typical Findings | Notes |
|---|---|---|---|
| EKG | Rhythm/ischemia | ST-T changes/arrhythmia | Serial |
| Troponin | Myocardial injury | Dynamic rise/fall | Trend |
| CXR | Pulmonary edema/size | Cardiomegaly/edema | |
| BMP/Mg2+ | Electrolytes/renal | Derangements | |
| CBC/Coags | Bleeding risk | Abnormal/INR |
Anticoagulation Snapshot
| Agent | Use |
|---|---|
| Direct oral anticoagulant | Outpatient eligible and stable |
| Heparin infusion | Inpatient or planned procedures |
| Thrombolytic | Massive PE with shock when no contraindication |
Pharmacology
| Medication | Mechanism | Onset | Role in Therapy | Limitations |
|---|---|---|---|---|
| Apixaban/Rivaroxaban | Direct factor Xa inhibition | Hours | First-line for most stable PE/DVT | Bleeding; interactions; ED use |
| Enoxaparin (LMWH) | Xa>IIa inhibition | Hours | Preferred initial AC in many stable cases; cancer VTE | Avoid severe renal failure; ED use |
| Unfractionated heparin (IV) | Antithrombin-mediated Xa/IIa inhibition | Immediate | Initial AC when lysis/cath possible or renal failure | Bleeding, HIT; monitor aPTT; ED use |
| Alteplase (systemic) | Plasminogen activation (fibrinolysis) | Rapid | Massive PE with shock or arrest | ICH/major bleed; contraindications; ED use |
| Catheter-directed therapy | Localized fibrinolysis/thrombectomy | Rapid | When systemic lysis high risk or ineffective | Bleeding; expertise required; ED use |
Prognosis / Complications
- Prognosis by ischemic burden/LV function
- Arrhythmias and HF are complications
Patient Education / Counseling
- Explain red flags and when to seek emergent care.
- Reinforce medication adherence and follow-up plan.
Notes
Consider pregnancy, renal failure, and contrast allergy when selecting tests and agents. Engage multidisciplinary response for high risk PE.
References
Use the Library, QBank, CCS, and analytics in one study workflow.
You just reviewed Pulmonary Embolism — ED Risk Stratification and Anticoagulation. MDSteps helps you turn that review into exam-style practice, missed-item flashcards, and a readiness dashboard that shows what to study next.
- 16,000+ USMLE-style questions across Step 1, Step 2, and Step 3
- CCS simulator with timed orders, live vitals, and case feedback
- Depth-on-Demand™ explanations and Anki-exportable flashcards
- Library + QBank + analytics for $27/month or $299 lifetime