Whisker Barrel Cortex said:
I can attest to the fact that mediastinal widening is an extremely non-specific and insensitive finding on chest x-ray. At least 30-40% of portable AP chest x-rays done in the emergency room have a wide appearing superior mediatinum due to various factors (rotation, AP positioning, lordotic, poor inspiration, etc). The "perfect" film is a near impossiblity on most ER patients. The vast majority of the time, unless the history is specifically looking for mediastinal widening, we do not call it. The number of chest CTs done would increase dramatically if we did call it. Occasionally, the mediastinum is obviously truly widened. Sometimes, if there is good technique, we will call more subtle widening.
Fair enough, but the point is that we haven't been specifically talking about (or, at least I'm not and haven't been) a windened mediastinum as an isolated finding.
Not to be overly simplistic and hopefully we can mostly agree here, there are basically four
very serious (i.e., requiring immediate treatment to prevent a
very bad outcome along with serious sequalae and morbidity if not mortality) differentials in chest pain: myocardial infarction, acute myocardial ischemia, pulmonary embolism, and dissecting aortic aneurysm. My point is that the clinician, for the most part, still has to make the diagnosis clinically with a high index of suspicion, and if his/her investigations to that point are not adding-up he/she must consider each of these possibilites in the differential - that's good medicine.
So, I'd agree that a widened mediastinum by itself may not be a good diagnostic indicator of aortic dissection. But, in light of other possible clinical findings, a widened mediastinum - even a questionable finding - becomes more likely clinically relevant, it's a routine test that can be done fairly quickly and is available in
every emergency department (unlike TEE or spiral CT, which may not be available and may add further delays waiting for results), and not doing a CXR in this instance clearly
is a failure of standard of care... and why do the test if you're not going to consider the results, whatever they may be? At least one person has posted some data (which has generated further debate) that agrees with what I'm saying, but I think people are over-scrutinizing it and perhaps missing the forest for the trees.
And, to make sure everyone understands and to thoroughly beat the dead horse, I have no idea how or when they arrived at the conclusion that Ritter had a dissecting aortic aneurysm, but obviously they
did get the diagnosis right - whether or not it was "too late" to do anything about it - and got him to the OR.
So, I want to know this: am I missing something here? Or, are people just now trying to split hairs about something that is done routinely, namely a portable CXR (which granted is usually an AP shot), but should still be considered significant within the other constellation of signs and symptoms associated with an acute aortic dissection? I'll admit that we don't have the complete picture in Ritter's case because we don't have his chart in front of us. But, how many of you think you would have missed this? How many dissections have you missed? How many have you seen? Would you not consider it highly in your differential if you saw a chest pain with a widened mediastinum? Is four hours unreasonable amount of time to come to this conclusion? Not to be accused of "Monday morning quarterbacking", but how many later-diagnosed aortic dissections were then thought to have had a widened mediastinum upon retrospective review of the chest x-ray? Has anyone done a blinded study on this? (I'm asking specifically Whisker Barrel Cortex because you may have more immediate access to a study such as this as a radiology resident.)
Outside of the discussion on the finer-points of diagnostic radiology, I seriously want to know. I'll be the first to admit that I still have a lot to learn.
-Skip
