Module 6 CVS continued: Aneurysms

Question 1

What is an aneurysm?

Answer 1

Localized abnormal dilation of a blood vessel

caused by a congenital or acquired weakness in the media

Question 2

What is a true aneurysm?

Answer 2

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

Question 3

What are the two types of true aneurysms?

Answer 3

Fusiform: uniform dilation of the entire circumference
Saccular: only a portion of the circumference is dilated

Question 4

What is a false or pseudoaneurysm?

Answer 4

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

Question 5

The etiology of aneurysms is a weakened media, what are 2 important causes?

Answer 5

1. atherosclerosis: AAA
2. 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

Question 6

What are the only two true aneurysms?

Answer 6

Berry

AAA

Question 7

What is the common location for AAA?

Answer 7

Infra renal abdominal aorta

Question 8

What is the predisposing factor for AAA?

Answer 8

Atherosclerosis

Question 9

What is the presentation for a AAA?

Answer 9

Asymptomatic or incidental finding on autopsy or physical exam looking for a pulsatile expansile mass

Question 10

What is the best investigation for a AAA?

Answer 10

Ultrasound or CT

Question 11

What is the diameter of the aorta at which the AAA will rupture?

Answer 11

over 5 cm

Question 12

what are the main complications of a AAA?

Answer 12

1. Main complication is rupture —– hypovalemic shock and sudden back pain (because aorta is retroperitoneal)
2. 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
3. Thrombus of the lumen leads to stasis and this leads to ischemia of lower extremities and therefore gangrene

Question 13

What is the common cause of syphilitic aneurysms (Luetic heart disease) = Thoracic aneurysm?

Answer 13

seen in the tertiary stage of syphillis; 15-20 years after initial infection with treponema pallidum bacteria

Question 14

What is the pathogenesis for thoracic aneurysm?

Answer 14

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)

Question 15

What is the mass effect of a thoracic aneurysm?

Answer 15

Mass Effect = compression of central structures

1. Trachea = cough and dyspnea
2. Esophagus = dysphagia
3. Left recurrent laryngeal nerve = hoarseness

Question 16

What is the best investigation for a thoracic aneurysm?

Answer 16

CT angiogram

ECG

Question 17

What is the best investigation for tertiary syphilis?

Answer 17

FTA-Abs test

fluorescent treponemal antibody absorption test

Question 18

On gross image how do a thoracic aneurysm appear?

Answer 18

Tree-bark appearance or intimal wrinkling —- due to obliteration of basovisceral and media scarring
remember that structurally intima is not affected just impression intima is making on the media

Question 19

So both Giant cell arteritis and thoracic aneurysm have tree-bark appearance on gross image, so what is the difference then?

Answer 19

Giant cell —- inflammation is in the intima and inner media scarring
Thoracic aneurysm—structurally intima is intact and the media is scarring

Question 20

Other then the already discussed mass effect, what are some other complications of a thoracic aneurysm?

Answer 20

1. Inflammation can spread to aortic roost where coronary arteries originate —- ischemia of myocardium —MI
2. Inflammation gets to aortic valve ring —— regur/incompetence/insufficiency (valve is just leaky now) —- due to the leakage there is volume overload this leads to —- cor bovinum (huge heart)—- left ventricular hypertrophy — left heart failure — pulmonary edema
   patient will have a murmur —- aortic valve undergoes regur during diastole when valve is closed
3. Stasis in heart causes mural thromboss = arrhythmias + mural thrombosis = embolic stroke

Question 21

What is the most common cause of death in patients with a thoracic aneurysm?

Answer 21

Left ventricular failure following aortic regur and therefore pulmonary edema and transudate

Question 22

What is the most common cause for aortic dissection?

Answer 22

Malignant HTN (and this leads to end organ damage) 
---not associated with atherosclerosis

Question 23

What is an aortic dissection?

Answer 23

Entry of blood in between and along the laminar planes of media with extension of blood along the length of the vessel = blood filled channel within aortic wall
Focal loss of elastic and smooth muscle fibers in the media of vessels

Question 24

what is the pathogenesis for aortic dissection?

Answer 24

intimal tear (from HTN) + defective media (Marfan’s syndrome or Ehlers Danlos)

Question 25

There are two types of aortic dissections, ascending and descending. The more dangerous one is ascending, what two types of ascending aortic aneurysm do you have?

Answer 25

blood can go forward (anterograde) or blood can go back (retrograde)

Question 26

What is the pathogenesis for anterograde aortic dissection?

Answer 26

Blood goes forward and compromises major vessels 1. Carotid arteries (Stroke) 2. Coronary arteries (MI) 3. Subclavian arteries (reduced blood pressure and pulse so unequal or asymmetric pulse and blood pressure in upper extremities) 4. Anterior Spinal Arteries (myelitis inflammation of the spinal cord next to GI arteries and renal arteries --- can cause renal failure)

Question 27

What is the pathogenesis for retrograde aortic dissection?

Answer 27

Rupture backward into the pericardial space ----- pericardial tamponade ---- Becks Triad (low BP, distant or muffled heart sounds, distended jugular veins) Also get aortic valve regur because the blood is gong to the heart

Question 28

The less dangerous of the aortic dissections is the descending which affects the lower extremities. what is the pathogenesis?

Answer 28

Below the renal arteries so only compromises blow frlow through the iliac, femoral and popliteal therefore these patients gets gangrene

Question 29

What is the presentation for a patient with aortic dissection and what do you see on xray?

Answer 29

Severe sudden chest pain that tears to the back | widened mediastinum on xray (Blood collecting in media)

Question 30

What is the best investigation for an aortic dissection?

Answer 30

CT angiogram

Question 31

What do you see on histology for an aortic dissection?

Answer 31

Blood dissects media into inner 2/3 and outer 1/3

Question 32

What is a double barrel aorta?

Answer 32

two intimal tears; another intimal tear that lets the blood go back into the true lumen and keeps patient alive

Question 33

What is the predisposing factor for a Berry Aneurysm?

Answer 33

Congenital defects with the vascular wall Marfan's syndrome and Ehler Danlos ---- due to cystic medial degeneration/necrosis --- easy for blood to dissect media ALSO AUTOSOMAL DOMINANT POLYCYSTIC KIDNEY DISEASE

Question 34

What is a common location of a berry aneurysm?

Answer 34

between anterior cerebral and anterior communicating

Question 35

What is the presentation for a berry aneurysm?

Answer 35

asymptomatic

Question 36

What is the presentation once the berry aneurysm ruptures?

Answer 36

``` During sex or taking a poop likely to rupture Subarachnoid hemorrhage (presents like meningitis) -- thunder clap headache, photophobia, neck stiffness, fever, seizures due to irritation of meninges ```

Question 37

What is the best investigation for a berry aneurysm?

Answer 37

CT scan without contrast (fresh blood so you dont need contrast)

Question 38

If you see nothing on a CT, what is the next step for a berry aneurysm?

Answer 38

Check for papilloedema if this is okay then do a lumbar puncture to check the CSF - --before 12 hours = RBCs - --after 12 hours = bilirubin (yellow) - xanthochromia

Question 39

What are some complications of a berry aneurysm?

Answer 39

Ischemic stroke because of cerebral vasospasms | Late complication: communicating hydrocephalus because of fibrosis of arachnoid vili or granulations

Question 40

What would you see on histology of a berry aneurysm?

Answer 40

Intima is fine but media is defective but still considered a true aneurysm but considered saccular due to outpouching to one side

Question 41

What is a mycotic (infectious) aneurysm?

Answer 41

Weakening of vessel wall by a microbial infection (salmonella, shigella; Aspergillus- angioinvasive)

Question 42

What are some site of origin for a mycotic aneurysm?

Answer 42

1. At site of sticking of a dislodged septic embolus within a vessel, as a complication of infective endocarditis 2. As an extension of adjacent suppurative process- TB infection or bacterial abscess 3. By circulating organism directly infecting the arterial wall 4. Leads to abdominal aortic aneurysm via septicemia