Aortic aneurysm (abdominal) and dissection Flashcards
What is the definition of an abdominal aortic aneurysm (AAA)?
A localised enlargement of the abdominal aorta such that the diameter is greater than 3 cm or more than 50% larger than normal. Most commonly fusiform.
Why is an AAA considered a significant condition?
Risk of rupture, which can lead to life-threatening internal bleeding.
Describe the pathophysiology of AAA development.
- Weakening of the aortic wall due to chronic inflammation and HTN,
- causing degradation of structural proteins like elastin and collagen,
- leading to dilation and potential rupture of the aorta.
Where are AAAs most commonly located? Below which landmark?
Most commonly infrarenal, with about one-third extending into the iliac arteries.
What is the prevalence of AAAs in the NHS UK AAA screening programme for men over 65?
The prevalence is 1.34%, meaning 1 in 70 men over 65 has an AAA.
List the major risk factors for developing an AAA.
- age (particularly over 65),
- male sex,
- smoking,
- hypertension,
- hyperlipidaemia
- diabetes
- family history,
- connective tissue disorders such as Marfan syndrome and Ehlers-Danlos syndrome.
What are the typical clinical features of a non-ruptured AAA?
Most AAAs are asymptomatic and detected incidentally.
If symptoms are present, they may include deep, gnawing abdominal/back pain, a pulsatile abdominal mass, fever (if infectious)
Due to non-specific abdominal/back pain, what other conditions might AAA mimic?
Renal colic, acute pancreatitis, diverticulitis, mesenteric ischaemia, GI perforation
Must rule out AAA if it is a differential
Symptoms of AAA rupture
Onset?
Sudden, severe abdominal or back pain, with pallour, SOB/tachycardia, syncope and vomiting.
Most important sign of a ruptured AAA
Hypotension/shock
Others: tachycardia, abdominal distension, pallor, syncope
Suspect rAAA in patients > 50 years presenting with abdominal/back pain and hypotension
What is the ‘classic triad’ of ruptured AAA?
- Flank/back pain
- hypotension
- pulsatile abdominal mass + tenderness
Only seen in about 50% of patients
2 features that should make you suspect ruptured AAA, regardless of likelihood of other differentials
Acute abdo/flank/back pain and hypotension.
Factors such as high BMI make a pulsatile abdominal mass much more difficult to detect.
What is the first-line imaging modality for screening and diagnosing an AAA?
Aortic ultrasound (USS)
First-line management for small AAA.
List non-pharmacological and pharmacological
Managing risk factors for vascular damage and rupture: smoking cessation, diet, exercise, anti-hypertensives and statins.
3 Indications of a non-ruptured AAA that require elective surgery?
What diameter –> urgent 2-week referral to vascular surgeons?
- > 5.5 cm,
- Getting larger rapidly (expanding <1cm/year),
- Symptomatic i.e. painful.
What is the recommended definitive imaging for a ruptured AAA?
Thin slice Computed Tomography Angiography (CTA) is recommended for ruptured AAA.
What is aortic dissection?
A tear in the intimal layer of the aorta, creating a false lumen through which blood can flow.
This can lead to life-threatening complications, including rupture and organ ischemia. Prompt diagnosis and management are crucial to improve outcomes.
List 2 possible features on a chest X-ray in aortic dissection.
The chest X-ray may show a widened mediastinum, dilated aortic arch.
What is the gold-standard imaging modality for aortic dissection?
CT angiography is the gold-standard imaging modality for definitive diagnosis of aortic dissection.
Which one is the false lumen?
The left one. Imagine it engulfing the true lumen and has horns.
