This month’s Save of the Month goes to Dr. Eric (Every)Rose(Has Its Thorn)Man.
The Case
A 53-year-old male with no reported past medical history presented with “sudden left side chest pain” x 15 mins.
Vitals in triage were as follows:
HR 125/min BP 163/113 mm Hg RR 20/min SpO2 96% on room air Temp 98.1 F
The patient described left-sided, “sharp” chest pain with no radiation that came on while he was sitting in a chair at home, 15 minutes prior to arrival. He had no associated vomiting, diaphoresis, dyspnea. He had no significant past medical history, family history, or social history (never smoker, no alcohol or drug use). His physical exam showed a slightly uncomfortable male with irregularly irregular heart sounds with intact and equal peripheral pulses. The rest of his exam was unremarkable.
His initial ECG was:
This was interpreted as atrial fibrillation with RVR and incomplete right bundle branch block (RBBB). There was no prior ECG for comparison.
Given the combination of chest pain and this ECG (possible new RBBB) a code H was called and iStat troponin sent. (Editor’s note: “new RBBB” is not suggestive of an occlusion MI; in this case, it would increase the likelihood of a clinically important PE.)
Cardiology evaluated the patient and they were concerned this was ACS. They recommended aspirin 324 mg, heparin drip, and admission to telemetry.
iStat troponin came back negative.
Then the patient’s chest x-ray showed this:
Dr. Roseman noted this mediastinum appeared wide. He ordered a CTA of the thoracic and abdominal aorta and found a type B descending aortic dissection extending into the left iliac artery. The patient was started on an esmolol drip and transferred to Maimonides Hospital for further management.
Congratulations Eric on this month’s Save of the Month.
A Word on Widened Mediastinum
Aortic dissection is thought to occur at a rate of 3-4 cases per 100,000 person-years (1), making it a rare diagnosis. Widened mediastinum carries a broad differential, but one in the setting of atraumatic chest pain should raise the concern for acute aortic dissection. The widening is due to the presence of a new dissecting false lumen next to the true lumen of the aorta.
Mediastinal width is measured at the level of the aortic knob. The classic teaching is anything > 8 cm on chest x-ray is a wide mediastinum. This number is based on studies in the 1970s looking at supine AP x-rays in trauma patients with concern for traumatic aortic rupture (2). However, mediastinal width can vary dramatically based on how the x-ray is performed – AP vs PA, upright vs supine, x-ray plate directly under the patient vs farther away. This has led people to question the usefulness of the 8 cm cutoff, although no more accurate cutoff has been suggested (3).
As far as accuracy, a recent meta-analysis showed that the presence of widened mediastinum had fairly poor sensitivity for identifying aortic dissection – about 85% (4). While the absence of widened mediastinum does reduce the likelihood of aortic dissection, it certainly does not rule it out. However, presence of a widened mediastinum in the setting of atraumatic chest pain should prompt at least a consideration of aortic dissection.
- LeMaire SA et al. Epidemiology of thoracic aortic dissection. Nat Rev Cardiol. 2011 Feb;8(2):103-13. doi: 10.1038/nrcardio.2010.187. Epub 2010 Dec 21.
- Marsh DG, Sturm JT. Traumatic aortic rupture: roentgenographic indications for angiography. Ann Thorac Surg 1976;21:337–40.
- Gleeson, et al. The mediastinum – Is it wide? Emerg Med J 2001;18:183–185 183.
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Ohle, et al. Clinical Examination for Acute Aortic Dissection: A Systematic Review and Meta‐analysis. Acad Emerg Med. 2018 Apr;25(4):397-412.
Charles Murchison
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