A 58-year-old man with a 10-day history of immobilization following a femur fracture presents with acute dyspnea, pleuritic chest pain, and tachycardia. D-dimer is elevated at 2.8 µg/mL. Regarding the clinical features and investigations in pulmonary embolism, all of the following are true EXCEPT:

Explanation

## Analysis of PE Clinical Features and Investigations ### Key Point: **Syncope is NOT pathognomonic for massive PE.** While syncope can occur in massive PE due to acute RV failure and cardiogenic shock, it is neither specific nor mandatory for the diagnosis. Many patients with massive PE do not present with syncope, and syncope can occur in other conditions (arrhythmias, vasovagal episodes, aortic dissection). The presence of syncope does *increase* suspicion for hemodynamically significant PE, but it does not mandate immediate thrombolysis without confirmatory imaging. ### Correct Statement Analysis | Feature | Truth | Clinical Significance | |---------|-------|----------------------| | Tachypnea (RR >20) | Present in >90% of acute PE | Most sensitive sign; may be absent only in small distal PE | | Normal D-dimer in low-risk | Excludes PE effectively | NPV >98% in low-risk patients; rules out disease | | Syncope + massive PE | Associated, NOT pathognomonic | Indicates hemodynamic compromise but not diagnostic alone | | Elevated troponin/BNP | Indicates RV strain | Prognostic marker; associated with higher mortality | ### High-Yield: **Syncope in PE context:** Occurs in ~5–13% of acute PE cases, usually in massive PE with acute RV failure. However, absence of syncope does NOT exclude PE, and presence does NOT confirm it without imaging. The diagnosis of PE requires objective confirmation (CT pulmonary angiography or V/Q scan), not clinical signs alone. ### Clinical Pearl: Troponin elevation (cTnI or cTnT) and elevated BNP/NT-proBNP in PE indicate myocardial injury from RV strain and are independent predictors of mortality. These are used for risk stratification in hemodynamically stable PE patients to identify those at higher risk who may benefit from advanced therapies. ### Warning: ~~Syncope = massive PE~~ — Syncope increases suspicion but is neither sensitive nor specific. Imaging confirmation is mandatory before treatment decisions. [cite:Harrison 21e Ch 297]