Podcast 116 - Pulmonary Embolism (Clinical Signs)


In this episode, Sam and I break down the different clinical signs and diagnostics of the dreaded pulmonary embolism. Check out the video podcast at the bottom of the page and use these notes to look at some of the specifics! Enjoy!


Generalized S/S


Common Signs and Symptoms according to Stein et al are listed below. Keep in mind that these are all comers. This is not separated into massive, sub-massive, or low risk - this is everyone combined. The more severe symptoms or heart failure and pulmonary compromise will be more prevalent in the massive / sub-massive groups.


Symptoms:

Dyspnea at rest or with exertion (73 percent)

Pleuritic pain (66 percent) Calf or thigh pain and/or swelling (44 percent)

Cough (37 percent)

Orthopnea (28 percent)

Wheezing (21 percent)

Hemoptysis (13 percent)


Signs:

Tachypnea (54 percent)

Calf or thigh swelling, erythema, edema, tenderness, palpable cords (47 percent)

Tachycardia (24 percent)

Rales (18 percent)

Decreased breath sounds (17 percent)

An accentuated pulmonic component of the second heart sound (15 percent)

Jugular venous distension (14 percent)

Fever, mimicking pneumonia (3 percent)


Check out this link for Specific sensitivities and specificities. Again, keep in mind that these are mixed results of different severities of pulmonary embolisms.


There are a couple tools that attempt to rule in or rule out pulmonary embolism based on signs and symptoms.


The PERC rule out for pulmonary embolism can be found here:

https://www.mdcalc.com/perc-rule-pulmonary-embolism


With this PERC rule out calculator, pay attention to the items that would have to be negative for a clinician to totally rule out pulmonary embolism (all of them). This tells us a lot about what signs, symptoms, and history would steer us towards the diagnosis of a pulmonary embolism.


The Wells Criteria for likelihood of a pulmonary embolism can be found here:

https://www.mdcalc.com/wells-criteria-pulmonary-embolism


Notice that the heaviest hitters on this calculator are: Signs / symptoms of a DVT, or if they've had previous pulmonary embolisms or DVTs, our clinical gestalt telling us that it's likely a PE, there is sinus tachycardia, and history that the patient has been immobile for a few days within the past 4 weeks.



ECG Findings


ECG findings by Macić-Dzanković & Pozderac-Memija for massive and sub-massive pulmonary embolisms:


Massive Embolisms:

  • Sinus-Tachycardia in 15/17 (88 %)

  • S1Q3T3 changes were presented in 12/17 (70 %)

  • Repolarization changes in right precordial leads in 13/17 (76 %)

  • New right bundle branch block in 2/17 (11.7 %)

Sub-Massive

  • Sinus-Tachycardia 16/23 (69.5 %)

  • S1Q3T3 10/23 (43 %)

  • Repolarization changes 13/23 (56.5%)

  • New RBBB 2/23 (8.6 %)

The thing about right sided heart issues, is that it's just a generic process. People talk about the sensitivity and specificity not being great, but you don't get these signs unless there is some pretty heavy duty backup into the right heart. Which isn't specific for pulmonary embolism. This backup could also be due to:

  • Pulmonary hypertension

  • L heart failure

  • Bronchospasm

  • Air trapping for some other reason

  • Tension pneumothorax

Essentially what we've learned is that these signs - pulmonary strain pattern, S1Q3T3, new complete or incomplete RBBB - might aim you towards the right side of the heart, but you’ve got to do some extra digging to figure out if PE is the culprit.


Example of S1Q3T3:


Example of pulmonary strain pattern:



Ultrasound Findings

DVT

The most sensitive and specific pulmonary embolism finding on ultrasound is a DVT. Most of the studies that examined this use duplex ultrasound which allows actual measurement of blood blow. I found this video super helpful with identifying the best places to look.

McConnell Sign

In both submassive and massive PE's, there is right ventricular dysfunction. One of the sonographic findings you may come across is McConnell's sign. This is demonstrated by akinesia (no movement) of the RV free wall. The apex will be the only area that is moving and has been described to look like a person jumping on a trampoline. Check out this video from 5MINSONO.



Now check out the episode!!




References


Stein, P. D., Terrin, M. L., Hales, C. A., Palevsky, H. I., Saltzman, H. A., Thompson, B. T., & Weg, J. G. (1991). Clinical, laboratory, roentgenographic, and electrocardiographic findings in patients with acute pulmonary embolism and no pre-existing cardiac or pulmonary disease. Chest, 100(3), 598–603. https://doi.org/10.1378/chest.100.3.598


Macić-Dzanković, A., & Pozderac-Memija, M. (2006). Specificity of electrocardiography and echocardiography changes at the patients with the pulmonary embolism. Bosnian journal of basic medical sciences, 6(4), 72–75. https://doi.org/10.17305/bjbms.2006.3126


Vaid U, Singer E, Marhefka GD, Kraft WK, Baram M. Poor positive predictive value of McConnell's sign on transthoracic echocardiography for the diagnosis of acute pulmonary embolism. Hosp Pract (1995). 2013 Aug;41(3):23-7. doi: 10.3810/hp.2013.08.1065. PMID: 23948618.