Aortic Dissection – Not something you see every day!
When you are asked to perform an Abdominal Ultrasound examination, with vague clinical history = “Ongoing back/loin pain for 10 years”.
My first thought is pathology such as: ? Kidney pathology ? Genuine Back pain. NOT Aortic dissection.
What causes an Aortic Dissection?
The Aorta is one of the major blood vessels that transports blood around the body. It’s wall is made up of three layers:
- Tunica intima, tunica media and tunic adventitia.
A dissection occurs with a tear in the intima. Blood enters this space and tears the intima layer away from the media layer, in effect generating a false channel/lumen.
In some life-threatening cases, it can cause a rupture in all three layers. Alternatively, if it only affects one or two layers, resulting in generalised back/flank pain can be felt and is treatable if detected early.
True cause is unknown, however Aortic dissections generally occur in:
- Males aged 50-70.
- > high blood pressure
- Conditions such as Marfans Syndrome, Ehlers-Danlos Syndrome, Turners Syndrome.
- Rare complication of Third Trimester pregnancy and post-partum.
- Blunt trauma.
- Complication following surgery i.e. Mitral valve replacement.
- Use of cocaine.
Following the Stanford classification there is two types of Dissections:
- Type A which involves the ascending aorta and arch – Surgical Management required.
- Type B involves the descending aorta – Medical management and blood pressure monitoring.
- Patients can also have a combination of both – This was the case with my particular patient.
Generally, symptoms can be similar to that of a heart attack, however specifically the following are indicators:
- Chest/back pain (Sever)
- Sudden onset of abdominal pain (Sever)
- Abnormal blood pressures/change in pulses between arms
- Loss of consciousness.
- Leg pain/difficulty walking
- Shortness/loss of breath
Ultrasound appearances on Ultrasound:
- Intimal flap on Ultrasound, has both a high sensitivity and specificity for a dissection.
Ultrasound being portable, rapid and easily accessible makes initially diagnosis ideal.
Optimal Imaging for correct diagnosis:
- Plain Chest Xray (CXR) – Aortic Dissection can be overlooked on a CXR in 12-18% of cases.
- Arterial enhanced contract CT (CTA). Gold Standard.
- Multi-planar transesophageal echocardiography.
- Rapid non contrast MRI (Good for review, but maybe utilised more in acute evaluation).
- Conventional digital subtraction Angiography (DSA) (However generally replaced by CTA).
- Surgery – Removal of the dissected aorta or blocking of the channel where blood is entering into the aortic wall is performed. Reconstruction is made with synthetic grafts/stents/tubing, and mesh.
- Medication – Medication is used to lower blood pressure and prevent the dissection from getting worse.
- Follow up treatment – Generally lifelong blood pressure medication and ongoing CTA/MRI for review.
- Bell D et al, 2017, Stanford classification of Aortic dissection, Radiopaedia (https://radiopaedia.org/articles/aortic-dissection)
- Fojtik JP, Costantino TG, Dean AJ. The diagnosis of aortic dissection by emergency medicine ultrasound. J Emerg Med. 2007;32:191–6.
- Golledge J, Eagle KA 2008. Acute aortic dissection. Jul 5;372(9632):55-66. Review. PubMed PMID: 18603160.
- Upadhye S, Schiff K 2012. Acute aortic dissection in the emergency department: diagnostic challenges and evidence-based management. Emerg Med Clin North Am. May;30(2):307-27, viii. Review. PubMed PMID: 22487109.