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| − | ==Arteriovenous Fistula== | + | ==[[Arteriovenous Fistula]]== |
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| − | ===Description===
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| − | *As the name implies, an arteriovenous fistula is an abnormal direct connection between an artery and a vein. This connection causes the capillary circulation to be completely ignored. We will concentrate on peripheral fistulas here.
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| − | '''The consequences of an arteriovenous fistula are the following:'''
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| − | 1. Increased blood return to the right heart raises cardiac output
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| − | 2. Decreased blood perfusion at the affected site
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| − | 3. Venous hypertension
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| − | *Predisposing causes of arteriovenous fistula formations are: trauma, surgery, neoplasia, etc.
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| − | ===Diagnosis===
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| − | ====History & Clinical Signs====
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| − | *Signs depend on where the AV fistula has formed.
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| − | -Subcutaneous edema
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| − | -Warm Swelling
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| − | -Inflammation
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| − | -Pain +/-
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| − | -Palpable vibration (thrill) over fistula
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| − | -Increased pulse & heart rate
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| − | -Audible continuous murmur over the fistula site
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| − | -Branham sign (decreased heart rate with surgical occlusion of blood flow to fistula)
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| − | ====Angiography====
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| − | -Abnormal direct connection between an artery and a vein
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| − | ====Ultrasonography====
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| − | -Abnormal flow visualized
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| − | ===Treatment===
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| − | -Surgical ligation of abnormal vessels to and from the fistula area
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| − | -(+/-) Amputation
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| − | ===Prognosis===
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| − | -Good with complete ligation and cessation of blood flow through the fistula
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| − | -Poor if surgical ligation is unsuccessful at stopping blood flow through the fistula
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