Physical exam PEARLS
- Remember Beck’s triad: low BP, distended neck veins, and distant, muffled heart sounds!
- You might also see a narrow pulse pressure
- There is a ddx for beck’s triad beyond just cardiac tamponade! Also think about acute pulmonary HTN (eg from PE)
- Pulsus paradoxus: >10mmHg drop in SBP on inspiration
- Thanks to Dan for reminding us that cutoff numbers are somewhat arbitrary (the higher the delta, the better!) and to Brad for sharing the Rational Clinical Exam article on this! The JAMA article includes sensitivity, specificity, and likelihood ratios for different cutoffs
- Remember the pathophys: normally, during inspiration à intrathoracic pressure becomes more negative à venous return increases. When this happens and you have a large pericardial effusion, the RV can’t stretch to accommodate the volume, so the septum bulges into the LV and resultant underfilling, leading to lower stroke volume (= a drop in SBP). There’s a great figure in the JAMA article 🙂
- Check out this awesome youtube video for the next time you need to perform a pulsus (from the Stanford 25): https://www.youtube.com/watch?v=jTsjCZ9QxW8
- When a patient is in afib, JVP is hard to assess!
- EKG: look for low voltage (from all the fluid), and electrical alternans (beat to beat variation from the heart moving around! NOT the same as pulsus which is variation between inspiration and expiration!)
- CXR: look for cardiomegaly (and compare the CXR to an OLD ONE!)! Per the JAMA article, sensitivity is 89%. You are more likely to see cardiomegaly when the effusion is subacute, as it takes time for the sac to stretch to accommodate the fluid. In acute pericardial effusions, there is no time for the sac to stretch and so you are more likely to see rapid development of Beck’s triad without cardiomegaly.
- TTE: if you see fibrinous material, this suggests that fluid has been accumulating for weeks!
Ddx for pericardial effusions PEARLS
- Fluid analysis is often NOT helpful as you can’t interpret it the way we can with ascitic or pleural fluid.
- But, if it’s BLOODY:
- 1/3 are malignant in a patient with a known h/o malignancy
- Only 2-3% are malignant in a patient without a known h/o malignancy
- General categories for ddx:
- TB (most common worldwide)
- Bacterial (purulent pericarditis – this is an emergency and must be drained! Pts often look quite sick)
- Malignancy (often see this in patients with KNOWN metastatic dz already; however, also remember the association between TNFa inhibitors and primary effusion lymphoma!)
- Autoimmune (RA, SLE most common)
- Metabolic (eg uremia, hypothyroidism)
- And…post-MI (this is most common!)
And, checkout our BLOG for a recent post on pericardial effusions during AM report: https://ucsfmed.wordpress.com/2016/01/19/am-cardiology-report-pearls-119-ddx-for-new-pericardial-effusions/