Tuesday, 21 October 2008

An Interesting Chest Radiograph

Dear Bloggers

Here is an interesting chest radiograph of an elderly patient with an acute onset of central chest and back pain which subsequently propogated to the abdomen. On admission, the patient had hypotension and distant heart sounds. The chest radiograph (with the history and physical findings) provided the diagnosis within seconds-- a proximal to distal aortic dissection (Stanford A type / DeBakey Type I).
Echocardiography revealed pericardial blood causing tamponade and an emergency thoracic contrast CT scan revealed a large Stanford type A dissection -- as suspected!

The ECG showed no signs of myocardial infarction which would be the differential diagnosis in such a case.

Remember that in patients with acute aortic dissection, the central chest pain can be severe. It may become a tearing pain in between the scapulae (interscapular pain). Such pain may further propogate down the back and into the abdomen as the aorta further dissects. Although this CXR is a classic example of a dissection, a chest radiograph can be normal in a proximal dissection. Even though it is often quoted that the blood pressure between the arms can be unequal it is not sensitive or specific for dissection and cannot be relied upon.

Good tests for investigating dissection include the quick bedside cardiac echo to look for haemopericardium and one may sometimes see the tear of the artery near to the aortic valve. However, the gold standard examination is the emergency CT.

If you have a high suspicion of dissection, please first stabilise your patient before moving them to the CT scanner -- remember the basics of Airway, Breathing and Circulation.

Please remember to give the patient adequate pain relief e.g. diamorphine, although bear in mind the potential hypotensive effects of the drug . It is not humane to leave patients in pain.

Ensure that the patient can be transported (if feasible) to a specialist cardiothoracic centre and if already there, ensure that the surgeons are told early rather than delaying for other reasons because 'time is artery'.

No comments: