EM Reflections Nov 2020 – Chest pain; expand the differential!

Authored and Edited by Dr. Mandy Peach

 

Big thanks to Dr. Paul Page for leading the discussions in November.

All cases are imaginary, but highlight learning points that have been identified as potential issues during rounds.

Chest pain is a huge topic – this is not a deep dive, but hopefully a helpful review of some useful information for on shift. This post assumes a basic knowledge of bedside ultrasound.

Chest Pain

  • The ‘don’t miss’ diagnoses
  • The ultrasound findings that can be helpful in shortening the differential
  • The evidence for ultrasound in some chest pain diagnoses
  • Select decision rules in chest pain
  • D-dimer and troponin and their uses
  • Ultrasound findings of cholecystitis

Case

48 yo male presents to the ED with 4 hours of substernal CP. He describes the pain as sudden onset and waking him from sleep overnight. He feels sweaty and has had 2 episodes of nausea/vomiting. He denies any fever or diarrhea. He had a similar episode last week that spontaneously resolved after 3-4 hours. He has no history of exertional chest pain. His cardiac risk factors include hypertension and his father died of ‘heart problems’ in his late 60’s.

An ECG is completed:

On exam his vital signs are within normal limits. He appears slightly diaphoretic and uncomfortable. Cardiorespiratory exam is unremarkable.

 

What are the BIG can’t miss diagnoses for chest pain? What bedside tool can be helpful in diagnosing some of these conditions?

Acute Myocardial Infarction (MI)

Pulmonary Embolism (PE)

Tension Pneumothorax

Aortic Dissection

Cardiac Tamponade

Esophageal Rupture

 

The ECG is unremarkable for ischemic change. You order a cardiac work up, including a CXR. While you await these results, you reach for your nearest ultrasound probe. You perform a cardiac and lung scan:

Figure 1 – normal subxiphoid view of the heart

Figure 2: Normal lung slide with visible A lines

You do not see any large pericardial effusion and on an eyeball observation the heart appears to have grossly normal form and function. The lung scan appears unremarkable with no sign of pneumothorax after viewing multiple rib spaces anteriorly and laterally.

 

How accurate is ultrasound at helping you rule in/out some of the major chest pain diagnoses?

Cardiac tamponade – Trained emergency physicians using beside ultrasound are quite effective at identifying significant pericardial effusions with a sensitivity of 96% and specificity of 98%1.

Figure 3: Large pericardial effusion with collapsing of RV

 

Pneumothorax – Lack of lung sliding and comet tails has a specificity of over 90% in ruling in pneumothorax. Time constraints? 1 view has comparable sensitivity to 4 views in picking up a clinically significant pneumothorax2

Figure 4: Absence of lung sliding or comet tails indicating pneumothorax

 

Pulmonary Embolism – Although no one finding is pathognomonic for PE, signs of RV dysfunction in the right clinical context is certainly suggestive of acute PE. Findings of:

  • RV enlargement equal or greater to that of the LV
  • RV systolic dysfunction (RV free wall hypokinesis) or
  • bowing of the RV into LV

have a 99% specificity for PE3.

Figure 5: Enlarged RV with free wall hypokinesis at the apex (McConnell’s sign)

Figure 6: Bowing of RV into LV in parasternal short view “D sign”

For advanced scanners, in patients with abnormal vitals (tachycardiac and hypotensive):

  • normal TAPSE
  • normal RV size
  • absence of RV flattening
  • absence of McConnell’s sign

significantly decreases the post-test probability for PE4

 

Aortic dissection – very specific findings – if you see a dissection flap you found it! If not, it’s still a high risk diagnosis you wouldn’t want to miss. There is evidence that when getting advanced cardiac views, suprasternal notch views and visualizing the abdominal aorta the sensitivity of POCUS is 86%5, however this did not translate into mortality benefit and is likely of more benefit for advanced scanners.

 

With normal vitals and ultrasound findings you feel confident there is no pneumothorax or tamponade. The probability of PE seems quite low given the history. Is there an objective way to risk stratify your patient for PE risk?

 

Apply the PERC rule 6 in the targeted low risk patients like this one where your physician gestalt of likelihood of PE < 15% . In the appropriate population this tool has a sensitivity of 96%;

The probability of him having a PE is < 2%.

 

You revisit the history and physical exam keeping in mind your remaining diagnoses of aortic dissection and esophageal rupture.

Are there any tools I can use to help decide if my patient is high risk for aortic dissection?

This tool is for low-moderate risk patients where dissection is in the differential.  When this rule was applied to a retrospective population only 4% of dissections were missed. When adding a normal CXR the miss rate decreased to 2.7%. Each feature equals 1 point. Essentially the absence of any high risk feature essentially rules out aortic dissection7. If more than 1 high risk feature, proceed to CT-A. If ≤ 1 this tool suggest ordering d-dimer.

Does d-dimer help rule out aortic dissection?

It’s controversial. If your patient is low risk and dissection isn’t high on your differential, a normal d-dimer doesn’t really add any value. If you order anyways and it is positive, it may lead to unnecessary testing. It certainly should not be used in isolation. The above tool combined with d-dimer had a sensitivity of 98.8% in one study, however this has not been externally validated8 – proceed with caution.

Your patient has no high risk features for aortic dissection.

 

Your patient did have episodes of vomiting – could they have a ruptured esophagus (Boerhaave syndrome)?

Mackler’s triad – vomiting, chest pain and subcutaneous emphysema – is present in 14-25% of cases so certainly not reliable. Patients can present with mediastinitis and abnormal vitals.CXR findings include 10:

With a normal CXR and normal vitals this is less likely.

 

So, you’ve considered the major diagnoses for chest pain and cardiac ischemia is left to consider – your first troponin result just become available – it is within normal range.

 

Can you use a single troponin to rule out a cardiac event?

You are now 4 hours from the onset of the event. Over his visit you have ordered a second ECG which is also normal. The troponin is  normal – you feel more reassured.  But your patient does have some risk factors for cardiac disease. You need to decide how at risk your patient is. You use the HEART score 11to help stratify:

Your calculated heart score is 3 which is low risk.

“A single undetectable hs-troponin after 3 hours of symptom onset or a delta 2-hr hs-troponin T <4ng/L plus normal serial ECGs and a HEART score of 0-3 rules out acute MI and lowers 30-day MACE to well below 1%, a threshold below which ancillary testing may cause more harm than benefit12.”

You feel quite confident your patient has no acute life-threatening cause of chest pain. You settle the pain and nausea in the ED and feel his is safe to go home. You suspect gastritis.

3 days later on shift you recognize the same patient – he again is complaining of chest pain, but today he looks much worst. You grab his chart – he is mildly tachycardiac, but otherwise vitals are normal. ECG again looks normal.
Today the patient describes having worsening nausea, fatigue and chest pain. His pain is more persistent and is not relieved with OTC medication at home. When you ask him to point to the pain he points towards his epigastric area – not substernal as he previously complained of.

This visit you complete an abdominal exam and find significant RUQ tenderness.

 

What are some other causes of chest pain, that although not immediately life threatening, should be considered13?

 

You grab your ultrasound probe as you suspect cholecystitis, what are the ultrasound findings?

Thickened gb wall > 3.5mm and fluid surrounding the gallbladder as seen above14.

You confirm cholecystitis and consult surgical service. On formal imaging the radiologist is concerned for potential perforation of the gallbladder.

Bottom line – chest pain has a broad differential! Grab your ultrasound probe and use some evidence based tools to help narrow your differential. Once life threatening causes ruled out consider other causes that can still affect patient morbidity.

 

References and further reading:

  1. Mandavia, Hoffner, Mahaney, Henderson (2001). Bedside echocardiography by emergency physicians. Annals of Emergency Medicine, Vol 38 (4); 377-382
  2. Michael Prats, MD. Comparison of Four Views Versus Single View for Pneumothorax. Ultrasound G.E.L. Podcast Blog. Published on November 07, 2016. Accessed on December 07, 2020. Available at https://www.ultrasoundgel.org/6.
  3. Pulmonary Embolism. The Evidence Atlas, The POCUS Atlas https://www.thepocusatlas.com/ea-echo
  4. Michael Prats. Focused Echo for Pulmonary Embolism in Patients with Abnormal Vital Signs. Ultrasound G.E.L. Podcast Blog. Published on February 17, 2020. Accessed on December 07, 2020. Available at https://www.ultrasoundgel.org/86.https://www.ultrasoundgel.org/posts/KsPSovvURE1CN7eZYELz1w
  5. Michael Prats. Return of the Aortic Dissection – POCUS Accuracy and Time. Ultrasound G.E.L. Podcast Blog. Published on August 31, 2020. Accessed on December 05, 2020. Available at https://www.ultrasoundgel.org/97.
  6. https://www.mdcalc.com/perc-rule-pulmonary-embolism
  7. Ohle, McIsaac, Atkinson (2019). How do I rule out aortic dissection? Just the Facts. CJEM 21(2): 34-36
  8. Nazerian, Mueller, Soeiro, Leidel, Salvadeo, Giachino et al. (2017). Diagnostic Accuracy of the Aortic Dissection Detection Risk Score Plus D-Dimer for Acute Aortic Syndromes: The ADvISED Prospective Multicenter Study. Circulation 137 (3): 250-258
  9. Cadogan, M. Boerhaave syndrome. Life in the Fast Lane. Published on Nov 3, 2020. https://litfl.com/boerhaave-syndrome/
  10. Diaz, G (2018). Boerhaaeve Syndrome. https://www.grepmed.com/images/5441/diagnosis-boerhaave-syndrome-signs
  11. Heart Score https://www.heartscore.nl/
  12. Low Risk Chest Pain and High Sensitivity Troponin – A Paradigm Shift. EM Cases. Published July 30, 2019. https://emergencymedicinecases.com/low-risk-chest-pain-high-sensitivity-troponin/
  13. Chest Pain. CanadiEM. Published June 1, 2020. https://canadiem.org/crackcast-e214-chest-pain/
  14. Flemming, Lewis, Henneberry. PoCUS – Measurements and Quick Reference. SJRHEM. Published 2017. http://sjrhem.ca/pocus-measurements-quick-reference/

All ultrasound gifs from The PoCUS Atlas https://www.thepocusatlas.com/

 

 

 

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EM Reflections – February 2018

Thanks to Dr. Paul Page for leading the discussions this month

Edited by Dr David Lewis 

 


 

Top tips from this month’s rounds:

Pleuritic Chest Pain – Don’t forget the Abdomen

Headache – Not always Migraine

Epistaxis – Posterior Bleed

CME QUIZ

 


Pleuritic Chest Pain – Don’t forget the Abdomen

The commonest causes of pleuritic chest pain (pleurisy) presenting to the ED include:

  • Pulmonary embolus
  • Pneumonia
  • Pericarditis
  • Myocardial infarct
  • Pneumothorax

Once these have been ruled out consider the following differential diagnosis:

ref: American Family Physician (May 2007)

 

Another differential to consider is:

Perforated peptic ulcer

This can result in localized sub-diaphragmatic peritonitis that can result in pleuritic chest pain

 

Tips:

  • If a CT Chest has been performed – look for free air under the diaphragm
  • Always document an abdominal exam when assessing a patient with pleuritic chest pain
  • Although radiologists are highly skilled, like any physician, they are not infallible. Conservative estimates suggest an error rate of 4%. See this excellent article: The Epidemiology of Error in Radiology and Strategies for Error Reduction
  • Wherever possible physicians should always review the images from CT and X-Ray prior to reading the formal radiology report.

Arrows depicting free air on erect CXR – note the double stomach bubble sign on the left

Free air seen on lower slice of CT Chest. Easily mistaken for bowel

 

 


Headache – Not always migraine

The commonest cause of headache presenting to the ED is migraine

The features of migraine headache are well documented in this article – The diagnosis and treatment of chronic migraine

 

The differential diagnosis for patients presenting with headache is large. This excellent website (https://ddxof.com/) provides algorithms to help consider the differential diagnosis in the cardinal EM presentations.

From: DDxof.com

 

Another differential to consider is:

Anemia

Sub-acute onset anemia secondary to chronic blood loss e.g menorrhagia, chronic GI bleed, etc can present with fatigue, visual disturbance and headache.

Tips:

  • Patients who present to ED with a new headache (no previous hx of primary headache syndrome or change in symptoms) should have baseline investigations including CBC and Glucose.
  • Always review the paramedic and triage notes for supplementary information and the presence of additional symptoms that may broaden or narrow the differential.
  • Patient ethnicity and skin colour may mask the presence of anemia.

 

 

 

 


Epistaxis – Posterior Bleed

Posterior epistaxis is a difficult condition to manage and is associated with a number of acute and serious complications. In this study, 3.7% required intubation.

The #FOAM Blog post provides an excellent outline to the management of posterior epistaxis – EMDocs.net

The Emergency Department Management of Posterior Epistaxis

 

Posterior Nasal Packing – video

 

 

Tips:

  • All cases of major bleeding, including epistaxis should be initially managed in the highest acuity areas of the ED. Patients can then be rapidly stepped down and relocated to lower acuity areas if determined to be lower risk after initial assessment.
  • Consider using a suction device to aid intubation in cases of massive obscuring oro/naso-pharynx haemorrhage.

PulmCrit: Large-bore suction for intubation: strategies & devices

 


 

 

CME QUIZ

EM Reflections - Feb 18 - CME Quiz

EM Reflections – Nov 17 – CME Quiz

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