PULMONARY EMBOLISM-INX

SUMMARY

1. CXR: rule out other pathology; Hampton hump (wedge-shaped defect above the diaphragm due to infarction), oligemia (Westermark sign), large right descending pulmonary artery (Palla sign)

2. ECG: tachycardia more common; large S wave in lead 1, large Q wave in lead 3, inverted T wave in lead 3 (S1Q3T3)

3. ABG: hypoxia & increased A-a gradient are key indicators of V/Q mismatch in large PEs, secondary RV failure also contributes to V/Q mismatch

4. D-dimer: good negative-predictive value, poor positive-predictive value; elevated in PE, heart failure, trauma/surgery, cancer

5. Trop T & I: elevated in 30-50% of PEs; likely result of right heart failure; elevated levels correlate with increased PE severity and short-term mortality

6. BNP: marker of increased morbidity & mortality

7. Ultrasound scan of legs: can add weight to PE diagnosis; important in prevention; incidence of embolization in below-knee DVTs is 50% less than more proximal thromboses; poor for detecting distal DVT (vessels harder to visualize) & abdominal-pelvic thrombi (most common source for PE)

8. CTPA: gold-standard for primary, non-invasive imaging

9. V/Q scan: test of choice for recurrent PEs with chronic VTE & in pregnant women (to minimize radiation); reported as normal/low/moderate/high probability; must factor in pre-test probability to ascertain probability of PE (Bayesian inference)
10. Echo: detects right-heart strain & prognosticating PE; incrased mortality in those with RV dysfunction & RV thrombus; consider urgent thrombolytic therpay in PE with fluid-refractory hypotension, RV strain & normal LV function

11. Pulmonary Angiogram: gold-standard, invasive; mortality < 0.1%; morbidity 1-2%

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].