Thanks to Dr. Paul Page for leading the discussions this month

Edited by Dr David Lewis 

Top tips from this month’s rounds:

Abdominal Aortic Aneurysm – Size matters, but it isn’t everything

CME QUIZ

Abdominal Aortic Aneurysm – Which patients require urgent consult / transfer ?

AAA is a disease of older age. The prevalence of AAA among men aged 65 to 80 is 4 to 6 times higher than in women of the same age. The Canadian Task Force on Preventative Healthcare have recently (2017) made the following recommendations on screening:

Recommendation 1: We recommend one-time screening with ultrasound for AAA for men aged 65 to 80. (Weak recommendation; moderate quality of evidence)

Recommendation 2: We recommend not screening men older than 80 years of age for AAA. (Weak recommendation; low quality of evidence)

Recommendation 3: We recommend not screening women for AAA. (Strong recommendation; very low quality of evidence)

Emergency Physicians are trained to recognize the signs and symptoms of ruptured AAA (hypotension, tachycardia, pulsatile abdominal mass, back pain) and are always on the lookout for those curveball presentations e.g renal colic mimic, syncope, sciatica etc.

With the organization of centralized vascular services predominating in the majority of developed national health systems, patients with ruptured AAAs are now being transferred for specialist care. Recent evidence from the UK suggests that this practice is safe with no observed increased mortality or length of stay. and other studies have shown a benefit, with reduced mortality post service-centralization.

While there maybe benefits of centralization for patients, vascular surgeons and health economies, the initial management of the patient with AAA disease can be increasingly challenging for the Emergency Physician, especially if they are located in a peripheral hospital.

Let us consider a few scenarios:

• A 70yr old man presents to a peripheral hospital (without CT), 120km from the vascular centre, with severe back pain and hypotension. Point of Care Ultrasound (PoCUS) confirms the diagnosis of a 7.5cm AAA.

This scenario is relatively straightforward. The patient is judiciously resuscitated (avoiding aggressive fluid infusion), and transferred, after discussion with on-call vascular surgery, as quickly as possible directly to the receiving hospital’s vascular OR.

• A 70yr old man presents to a peripheral hospital (without CT), 120km from the vascular centre, with moderate flank pain and normal vital signs. They are known to have a 3.7cm AAA (last surveillance scan 6 months ago). PoCUS confirms the presence of an AAA measuring approx. 3.7cm. Urinalysis is negative.

This scenario is also relatively straightforward. While the cause of the flank pain has not been determined, the risk of AAA rupture is highly improbable. For men with an AAA of 4.0 cm or smaller, it takes more than 3.5 years to have a risk of rupture greater than 1%. Given the stable vital signs, low pain score and lack of significant change in AAA size, this patient can be safely worked-up initially at the peripheral hospital pending transfer for abdominal CT if diagnosis remains unclear or symptoms change.

• A 70yr old man presents to a peripheral hospital (without CT), 120km from the vascular centre, with moderate flank pain and normal vital signs. They have no past medical history. PoCUS confirms the presence of a new 4.7cm AAA.  

This scenario starts to become more challenging. Is the AAA leaking? Is the AAA rapidly expanding? Has PoCUS accurately measured the AAA size, Is the AAA causing the symptoms or is there another diagnosis? While this AAA is still below the elective repair size (5.5cm), the rate of growth is not know (and this is important), 4.7cm AAAs do occasionally rupture and rapidly expanding AAA’s can cause pain (the phenomena is more common in inflammatory and mycotic aetiologies). In this scenario the safest approach would be to organize transfer for an urgent CT and to arrange for Vascular Surgey consult immediately thereafter.

Salmonella aortitis may appear after a febrile gastroenteritis. The common location of primary aortitis and aneurysm formation is at the posterior wall of the suprarenal or supraceliac aorta – Ann Vasc Dis. 2010; 3(1): 7–15.

Aortitis is the all-encompassing term ascribed to inflammation of the aorta. The most common causes of aortitis are the large-vessel vasculitides including GCA and Takayasu arteritis. The majority of cases of aortitis are non-infectious, however an infectious cause must always be considered, as treatment for infectious and non-infectious aortitis is significantly different.

This article provides a detailed summary of the diagnosis and management of Aortitis

CME QUIZ