Module 6 CVS continued: Aneurysms Flashcards
What is an aneurysm?
Localized abnormal dilation of a blood vessel
caused by a congenital or acquired weakness in the media
What is a true aneurysm?
Complete but attenuated (thin) vessel wall
involve all 3 layers of blood vessel
blood remains within the confines of the circulatory system
atherosclerotic, syphilitic, congenital and vascular aneurysm
What are the two types of true aneurysms?
Fusiform: uniform dilation of the entire circumference
Saccular: only a portion of the circumference is dilated
What is a false or pseudoaneurysm?
Extravascular hematoma (Collection of blood outside blood vessels) that communicated with the intravascular space; blood flows outside the circulatory system Involves only adventitia wall defect: all 3 layers damaged
The etiology of aneurysms is a weakened media, what are 2 important causes?
- atherosclerosis: AAA
- Cystic Medial Necrosis: auto dom disorder; breakdown of collage, elastin, smooth muscle + accumulation of mucopolysaccharide in wall (Cyst like spaces) = weak aortic wall —- dilation of aortic root w/risk for dissection
What are the only two true aneurysms?
Berry
AAA
What is the common location for AAA?
Infra renal abdominal aorta
What is the predisposing factor for AAA?
Atherosclerosis
What is the presentation for a AAA?
Asymptomatic or incidental finding on autopsy or physical exam looking for a pulsatile expansile mass
What is the best investigation for a AAA?
Ultrasound or CT
What is the diameter of the aorta at which the AAA will rupture?
over 5 cm
what are the main complications of a AAA?
- Main complication is rupture —– hypovalemic shock and sudden back pain (because aorta is retroperitoneal)
- Renal failure die to compression of ureters by the aneurysm. called mass effect. patient will get hydronephrosis (retrograde flow of urine) which will leads to renal failure. patient will also get pylonephritis due to urinary stasis
- Thrombus of the lumen leads to stasis and this leads to ischemia of lower extremities and therefore gangrene
What is the common cause of syphilitic aneurysms (Luetic heart disease) = Thoracic aneurysm?
seen in the tertiary stage of syphillis; 15-20 years after initial infection with treponema pallidum bacteria
What is the pathogenesis for thoracic aneurysm?
Starts in vaso vasoroum which supplies the media — obliterative end arteritis —- lymphocytes, plasma cells, and mononuclear cells in adventitia — occlusion of vaso vasorum due to thrombus —- necrosis of media —- ischemia causes loss of elastic fibers — chronic inflammation —- fibrosis —- vessel becomes weakened —- aneurysm
(lymphocytes because its an organism)
What is the mass effect of a thoracic aneurysm?
Mass Effect = compression of central structures
- Trachea = cough and dyspnea
- Esophagus = dysphagia
- Left recurrent laryngeal nerve = hoarseness
What is the best investigation for a thoracic aneurysm?
CT angiogram
ECG