Case of the Month #9, Answer

This month’s winner is the one and only ablumenberg, whose intimidatingly thorough answer frightened off all other contenders.

Recap

Older lady, many medical problems, here for epigastric discomfort now with acute decompensation as evidenced by her tachycardia and diaphoresis while in your imaginary ED.

This patient is clearly in shock. Let's start with a broad diff dx for shock

Hypovolemic including hemorrhagic versus dehydration, cardiogenic, obstructive such as tamponade, PE, tension pneumothorax, distributive including sepsis, cyanide toxicity, neurogenic. Here, the top differential includes: tamponade and perforated ulcer (sepsis/distributive).

To review the initial ECG...

as ablumenberg commented, this ECG is consistent with pericarditis.

As you can see, there are generalized ST elevations, ST depressions in V1 and AVR, and PR depressions! Note there is no electrical alternans. ECG findings for pericarditis are well described in the textbook, BUT rarely progress as depicted.

The 4 stages of are:
1. Generalized STE, PR depressions, ST depressions in AVR

2. T wave flattening throughout

3. T wave inversions

4. Normal

So what do you do about this?

The usual – ABC’s (intact), IV/O2/Monitor (done already). Consider IVF (only harmful if cardiogenic shock) CXR for ptx or air under the diaphragm and ECG to look for STEMI vs etiology of tachydysrhythmia…and while you are waiting for those to get done – Ultrasound! I recommend the RUSH protocol (see paper here and EMCrit version here). The initial ECG should heighten your suspicion for pericarditis and tamponade.

For this case, repeat ECG was rate 150, mildly irregular, with the same ST segments as seen previously. CXR was unchanged without air under the diaphragm.

RUSH exam revealed no signs of right heart strain, no signs of pneumothorax, BUT a large pericardial effusion! Though there was no RV collapse or obvious atrial compression, there was a plethoric IVC! The treatment: pericardiocentesis or, if stable enough, an emergent pericardial window.

So what are the signs of pericardial tamponade on ultrasound?

Obviously, you need an pericardial effusion to have tamponade – importantly, the size of the effusion does not matter. What matters is the speed at which the effusion develops. Important indicators of tamponade include: Right atrial or right ventricle collapse during diastole. To help, you can use M mode through the anterior leaflet of the mitral valve and right ventricular free wall. This can give you defined diastole – when the mitral valve is open – while showing you the motion of the ventricular wall. If there is any collapse of the ventricular free wall during diastole, the patient is in tamponade. Another indicator is a plethoric IVC in a patient with vital signs or other indicators of shock. For more information, see a paper here or a podcast here.

By Dr. Andrew Grock

References

Life in the Fast Lane: http://lifeinthefastlane.com/ecg-library/basics/pericarditis/

Tintinally’s 7th ed

EMCrit:http://emcrit.org/rush-exam/

Adam Goodman, Phillips Perera, Thomas Mailhot, and Diku Mandavia. The role of bedside ultrasound in the diagnosis of pericardial effusion and cardiac tamponade. J Emerg Trauma Shock. 2012 Jan-Mar; 5(1): 72–75.

Dina Seif, Phillips Perera, Thomas Mailhot, David Riley, and Diku Mandavia. Review Article Bedside Ultrasound in Resuscitation and the Rapid Ultrasound in Shock Protocol. Critical Care Research and Practice Volume 2012, Article ID 503254, 14 pages doi:10.1155/2012/503254

Ultrasound Podcast: http://www.ultrasoundpodcast.com/2013/11/pericardial-tamponade-learn-know-foamed/