Boring EM - Posted by Shabaz Syed on 2015, 08, 03
"Take Home points
AD is a rare disease, and as emergency physicians we should be screening patients for the potentialto have this disease entity. It is therefore more useful to identify features to reassure us that a patient is indeed low risk, and negate the need for further investigations, which is why negative LHR’s are an important aspect of this diagnostic consideration.
How should you apply this information?
- The AHA guidelines are too inclusive and result in the unnecessary scanning of patients.
- The decision to perform a CT scan to investigate for AD depends on your pretest probability – which can be modified using the LHR’s of various historical and physical exam features.
- Ultimately when your think that your patient is low risk, or you have a low pretest probability, you can probably stop there and consider an alternative diagnosis.
- In the patient presenting without high risk features, lacking immediate onset chest pain, vascular pain/migratory features, a normal clinical exam and CXR – aortic dissection is highly unlikely and doesn’t warrant significant consideration.
- With the exception of neurological findings, one individual historical or physical exam finding does not necessarily warrant investigation for AD, recognizing that this is a deviation from the proposed AHA guidelines, and therefore requires the clinician’s interpretation of the data available (i.e.: pretest probability).
- BP differential between arms is not useful, and instead we should be looking for pulse differences amongst extremities.
- D-Dimer adds very little to your workup of the patient with aortic dissection.
- D-Dimer is not validated in those that are intermediate to high risk.
- In low risk patients, it does not significantly change your pretest probability, and shouldn’t be utilized."
http://boringem.org/2015/08/03/could-my-patient-have-an-aortic-dissection/