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| ==Background==
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| *Infrarenal diameter >3cm or >50% increase in size of diameter
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| **85% of cases are infrarenal due to lack of vasovasorum <ref name="NJM"></ref>
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| *M to F ratio is 4:1
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| *Rupture Risk
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| **<4cm: low risk for rupture
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| **4-5cm: 5 year risk 3-12%
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| **>5cm: 25-41%
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| **Rupture possible at any size, most commonly >5cm
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| **Mortality with rupture: 85-90% <ref name="NJM">Kent, K. Abdominal Aortic Aneurysms. The New England Journal of Medicine. 2014; 371:2101-8. DOI: 10.1056/NEJMcp1401430 </ref>
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| ===Risk Factors===
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| *Smoking
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| **Risk factor most strongly associated with AAA
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| **Also promotes the rate of aneurysm growth
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| *Age (prevalence is negligible in age <50yrs)
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| *Family history
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| *Hypertension
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| *Hyperlipidemia
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| *Fluoroquinolone use <ref>P. Wendling for Medscape. FDA Warns of Aortic Aneurysm Risk with Fluoroquinolones. https://www.medscape.com/viewarticle/906867. Accessed 12/26/2018.</ref>
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| ==Clinical Features==
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| *Classic triad is [[abdominal pain|pain]] + [[hypotension]] + pulsatile mass
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| **Pain often described as sudden, severe, radiating to back
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| *[[Syncope]] (10%)
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| *Signs of [[Retroperitoneal hemorrhage]]
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| *Massive [[GI bleed]] from erosion into intestines
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| *Pain + AAA = rupture until proven otherwise
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| *Acute abdomen + hypotension = possible rupture
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| *Gross [[hematuria]] can be caused by an aortocaval fistula (very rare)
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| ==Differential Diagnosis==
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| {{Abdominal Pain DDX Diffuse}}
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| {{Lower back pain DDX}}
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| ==Evaluation==
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| [[File:AAA.png|thumb|AAA]]
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| [[File:AAA_with_Thrombus.gif|thumbnail|AAA with Thrombus<ref>http://www.thepocusatlas.com/aorta-1/</ref>]]
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| *[[Aortic ultrasound|Ultrasound]]
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| **~100% sensitive for increased diameter
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| **Cannot reliably visualize rupture
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| *CT
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| **~100% sensitive for increased diameter and rupture
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| **IV contrast is preferred but not essential
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| ==Management==
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| ===Rupture===
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| *Do not waste time in ED trying to "stabilize" patient
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| *Immediate surgery consultation/ go to OR
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| *Crossmatch 6 units of pRBC
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| *Pain control (avoid hypotension)
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| *Antihypertensives (use with caution, goal SBP 110-120 mmHg or MAP 70-80)<ref>Reed, K. Aortic Emergencies, EB Medicine. 2006.</ref>
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| **[[Labetalol]]: 20mg IV, then 40-80mg IV q10 min (max 300mg)
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| **[[Esmolol]]: Bolus 500 mcg/kg, then 50-200 mcg/kg/min
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| **[[Nitroprusside]]: 0.3 - 0.5 mcg/kg/min, titrate to max 10 mcg/kg/min
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| *Controversial
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| **Too little (ischemia), too much (increased bleeding)
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| ***Consider allowing for permissive hypotension (SBP 80-100) in conscious patient
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| **[[Pressors]]
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| ***[[Norepinephrine]] 0.05mcg/kg/min IV; titrate by 0.02mcg/kg/min q5min
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| ***[[Phenylephrine]] 100-180mcg/min; titrate by 25mcg/min q10min
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| ***[[Dopamine]] 5mcg/kg/min; titrate by 5mcg/kg/min q10min
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| ===Asymptomatic===
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| *Prompt vascular surgery outpatient follow-up appt
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| **Endovascular (75%) vs open repair
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| *Screening frequency:
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| **3-4 cm diameter: 12 months
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| **4-5 cm diameter: 6 months
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| **5-6 cm diameter: 1 month
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| *Elective Surgery indicated if:
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| **AAA > 5.5 cm in men <ref name="NJM"></ref>
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| **AAA > 5 cm in women <ref name="NJM"></ref>
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| **increase in size > 1 cm/year
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| **increase in size > 5 mm/6 months
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| ==Complications==
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| *[[Aortoenteric fistula]]
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| *[[Aortocaval fistula]]
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| *[[Inflammatory abdominal aortic aneurysm]]
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| *[[Acute limb ischemia]] - embolism to lower extremities
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| ==Disposition==
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| *Admit to OR in cases of ruptured OR
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| *Vasc surgery follow up in asymptomatic cases
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| ==References==
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| <references/>
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| [[Category:Cardiology]]
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| [[Category:Vascular]]
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