A bedside ultrasound of the heart, demonstrates a pericardial effusion. He has a ascending thoracic aorta, with carotid extension leading to a stroke.
Thoracic aortic dissection is often called the great mimic because it can look like a subarachnoid haemorrhage, an inferior myocardial infarction, a stroke, a vascular event of the lower limbs, a testicular pain and more…. It has a bimodal distribution. In the young, the cause is usually genetic, in the older patient, it is an issue of the intima, secondary to hypertension. It is far less common then cardiac ishaemia- about one thousandth the rate. However it can have dire consequences, with an 80% chance of mortality when associated with rupture and up to 2% rate of mortality per hour, untreated.
Why do we miss it? Because we don’t think of it.
What are the risk factors?
Here is the key to diagnosing thoracic aortic dissection.
Remember these 5 things:1 Chest pain PLUS
-Neurological symptoms and/or
2 Symptoms above and below the diaphragm
3 In the patient with syncope (occurs in up to 13% of cases)
4 In the patient with inferior myocardical infarction
-It can occur in up to 5% of those with thoracic aortic dissection.
5 Cephalgia – beware the sudden onsent of headache.
In the landmark study, the IRAD (The International Registry of Acute Aortic Dissection) by Hogan P G et al, JAMA, 2000;283;897-903 the symptoms and clinical findings are shown.
Symptom: Chest Pain
The position of the pain is important, as it may indicate where the dissection is. Anterior chest pain is associated with dissection of the ascending aorta, whereas pain into the upper back is associated with dissection of the arch, moving down to the descending aorta. Lower back pain occurs as the dissection descends.
Position of Pain
Dissection can occur along
I would also add, do a quick bedside ultrasound of the heart looking for a pericardial effusion.
THE CHEST X-RAY
One of the main areas of litigation in this condition is fibrinolysis being given in an inferior infarction without a chest x-ray. The patients in question had a dissection and the use of lysis was fatal.
How good is the chest x-ray?
CHEST X-RAY FINDINGS
Think of it in other causes
Think of it as a sudden severe headache. Certainly chase the more likely diagnosis of subarachnoid haemorrhage. However if nothing is found, think of carotid malperfusion. A good case study to read is Notre, B et al, Arotic Dissection mimicking subarachnoid haemorrhage, Anesth Analg 2005, July: 101 (1) 233-4.
A quick word about D-Dimer for diagnosing Dissection
There has been a lot of interest and ruling out a dissection with a normal D-Dimer.
Most studies are retrospective and some have prospective cohorts.
We need appropriate validated studies as there are major consequences of missing this condition.
This is not prime time yet. We cannot rule it out with a normal d-dimer.
- See more at: http://www.resus.com.au/blog/thoracic-aortic-dissections-5-things-to-know-to-make-the-diagnosis/#sthash.2keYrKiB.dpuf