An abdominal aortic aneurysm is a localized dilatation of the abdominal aorta, that exceeds the normal diameter of the abdominal aorta by more than 50%. The normal diameter of an aorta depends on the patient's age, sex, height, weight, race, body surface area, and baseline blood pressure. On average, the normal diameter of the infrarenal aorta is 2 cm, and therefore a true AAA measures 3.0 cm or more. Aortic ectasia is a mild generalized dilatation (<50% of the normal diameter of ≤ 2.9 cm) that is due to age-related degenerative changes in the vessel walls.
Causes
Life Threatening Causes
Abdominal aortic aneurysm is a life-threatening condition and must be treated as such irrespective of the underlying cause.
A Focused Initial Rapid Evaluation (FIRE) should be performed to identify patients in need of immediate intervention.
Abbreviations:
Complete Diagnostic Approach
A complete diagnostic approach should be carried out after a focused initial rapid evaluation is conducted and following initiation of any urgent intervention.
Characterize the symptoms:
❑ Asymptomatic
❑ Majority of the patients are asymptomatic (Detected incidentally)
❑ Symptomatic but not ruptured
❑ Pain with an indolent onset
❑ Abdominal pain
❑ Back pain
❑ Groin pain (scrotum)
❑ Pulsating sensations in the abdomen
❑ Limb ischemia (suggestive of embolism of thrombus or atherosclerotic debris)
❑ Systemic manifestations(suggestive of primary aortic infection with aneurysm formation or secondary infection of an established AAA)
❑ Fever
❑ Malaise
❑ Symptomatic and ruptured
❑ Severe pain described as severe, sudden, persistent, or constant
❑ Back/flank pain (suggestive of proximal aortic rupture near the renal arteries)
❑ Abdominal/pelvic pain (distal rupture near the iliac bifurcation)
❑ Pain that radiates to the groin or thigh (suggestive of lumbar nerve irritation)
❑ Discoloration of the scrotum (Bryant’s sign)(suggestive of retroperitoneal hematoma)
❑ Ecchymosis of the proximal thigh (Fox’s sign)
Extremities
❑ Peripheral artery aneurysm (eg, femoral, popliteal)
❑ Signs of limbischemia (suggestive of embolism of thrombus or atherosclerotic debris from the aneurysm)[8][9]
❑ Painful
❑ Pulseless
❑ Pale in color
❑ Perishing cold- Freezing cold feeling, a painful cold temperature.
❑ Paraesthetic feeling such as burning or tingling
❑ Paralysed
❑ Claudication (suggestive of peripheral artery disease)
❑ Patients presenting with classic symptoms and signs of rupture
❑ Abdominal/back/flank pain,
❑ Hypotension
❑ Pulsatile mass
Order lab tests:
❑ For patients with acute abdominal complaints
❑ Complete blood count
❑ Electrolytes
❑ Blood urea nitrogen
❑ Creatinine
❑ Additional tests for patients presenting with shock
❑ Liver function tests
❑ Coagulation parameters
❑ Fibrinogen
❑ Fibrin split products
❑ Arterial blood gases
❑ Lactate level
❑ Cardiac enzymes
❑ Toxicology studies
❑ Order Imaging study
❑ Abdominal ultrasound (preferred in asymptomatic patients)
❑ Measure the anteroposterior (AP), longitudinal and transverse dimensions of the aorta
❑ Do a Focused Assessment with Sonography in Trauma (FAST) exam to rule out retroperitoneal hematoma (in hemodynamically unstable patients)
❑ Computed tomography (CT)(used in symptomatic but stable patients)
❑ Differentiates ruptured from nonruptured aneurysm
❑ Can evaluate suprarenal aneurysms
❑ Helps defining the extent of the aneurysm to plan for surgery
❑ Magnetic resonance imaging (MRI) (used in known AAA (unrepaired or post-repair) with contraindications to contrast)
❑ Take this patients to the operating room for immediate management and
diagnose intraoperatively
❑Imaging is highly desirable, but is not absolutely required prior to intervention
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Treatment
Shown below is an algorithm summarizing the treatment of Abdominal aortic aneurysm according the the [...] guidelines.
Do's
Don'ts
↑Singh, K.; Bønaa, KH.; Jacobsen, BK.; Bjørk, L.; Solberg, S. (2001). "Prevalence of and risk factors for abdominal aortic aneurysms in a population-based study : The Tromsø Study". Am J Epidemiol. 154 (3): 236–44. PMID11479188. Unknown parameter |month= ignored (help)
↑Santosa, F.; Schrader, S.; Nowak, T.; Luther, B.; Kröger, K.; Bufe, A. (2013). "Thoracal, abdominal and thoracoabdominal aortic aneurysm". Int Angiol. 32 (5): 501–5. PMID23903309. Unknown parameter |month= ignored (help)
↑Rapini, Ronald P.; Bolognia, Jean L.; Jorizzo, Joseph L. (2007). Dermatology: 2-Volume Set. St. Louis: Mosby. ISBN1-4160-2999-0.CS1 maint: Multiple names: authors list (link)
↑Greenhalgh RM, Powell JT. "Endovascular repair of abdominal aortic aneurysm". N. Engl. J. Med. 358 (5): 494–501. doi:10.1056/NEJMct0707524. PMID18234753.