Peripheral Vascular Disease III - Abdominal Aortic Aneurysm (AAA)

Question 1

what is an aneurysm?

Answer 1

dilation of a vessel by more and 50% of its normal diameter

Question 2

what is the normal aortic diameter?

Answer 2

1.2-2.0cm

Question 3

what are the 2 types of aneurysm?

Answer 3

1) true aneurysm

2) false aneurysm

Question 4

in true aneurysm, describe the vessel wall?

Answer 4

= the vessel wall is intact (all 3 layers)

Question 5

in false aneurysm, describe the vessel wall?

Answer 5

= there is a breach in the vessel wall (surrounding structures act as vessel wall)

Question 6

what are the 3 shapes of an aneurysm?

Answer 6

1) saccular
2) fusiform
3) mycotic

Question 7

how do mycotic aneurysms arise?

Answer 7

• arises secondary to an infectious process, involving all 3 layers of the artery

Question 8

related to pathogenesis, what happens in abdominal aortic aneurysm?

Answer 8

= medial degeneration

Question 9

what happens in medial degeneration?

Answer 9

• regulation of elastin/collagen in aortic wall
• aneurysmal dialtion
• increase in aortic wall stress
• progressive dilation

Question 10

who is at the greatest risk of developing abdominal aortic aneurysm?

Answer 10

1) increases with age
2) make gender
3) smoking
4) hypertension
5) diabetes
6) raised cholesterol

Question 11

what commonly happens in people with AAA?

Answer 11

popliteal aneurysms

Question 12

what do the majority of AAA present with?

people who present with this, what are they at risk or?

Answer 12

asymptomatic

Risk of = rupture

Question 13

if people with AAA present with symptoms, what are they?

In people who present with symptoms, what can you exclude?

Answer 13

1) pain
- can mimic renal colic

2) trashing
= bits of plaque break off and travel through aorta

3) rupture

You can exclude rupture.

Question 14

what sort of pain is AAA rupture?

Answer 14

sudden onset of epigastric, central pain.

- may radiate through back

Question 15

what may rupture of AAA mimic?

Answer 15

mimic renal colic

Question 16

what does rupture of AAA result in?

Answer 16

collapse

Question 17

on examination, what might you find in a patient with ruptured AAA?

Answer 17

• may look well
• hypo/hypertension
• pulsatile, expansile mass +/- tender
• transmitter pulse
• peripheral pulses

Question 18

what are the 2 types of rupture?

Answer 18

1) retroperitoneal, contained rupture

2) free intra-peritoneal rupture = fatal

Question 19

how can you image AAA?

Answer 19

• duplex ultrasound

= asymptomatic/surveillance

Question 20

in the duplex ultrasound, what are you looking at?

Answer 20

AP diameter and involvement of iliac arteries

= it only tells you there is an AAA or not and its AP diameter

Question 21

what other imaging can you do for AAA?

Answer 21

CT scan

Question 22

what are you looking at in a CT scan?

Answer 22

= arterial phase

• IV contrast
• commence when contrast is in arterial system

Question 23

what is the only imaging method to identify ruptured AAA?

Answer 23

CT scan

Question 24

what are the 2 ways of managing an AAA?

Answer 24

1) open repair

2) endo-vascular aneurysm repair (EVAR)

Question 25

to repair an AAA, what 4 things can open repair involve?

Answer 25

1) laparotomy 2) clamp aorta + iliac 3) Dacron graft 4) tube vs bifurcated graft

Question 26

what is the other way of managing an AAA?

Answer 26

endo-vascular aneurysm repair

Question 27

what happens in endo-vascular aneurysm repair?

Answer 27

- exclude AAA from inside the vessel - inserted via peripheral artery - X-ray guided - modular components

Question 28

what are the 3 types of acute limb threat?

Answer 28

1) acute limb iscahemia 2) acute or chronic limb iscahemia 3) diabetic foot sepsis

Question 29

what is acute limb ischaemia?

Answer 29

sudden loss of blood supply to a limb

Question 30

what causes acute limb ischaemia?

Answer 30

= occlusion of native artery or bypass graft

Question 31

what causes sudden occlusion in acute limb ischaemia?

Answer 31

1) embolism 2) athero-embolism 3) arterial dissection 4) trauma 5) extrinsic compression

Question 32

what are the 6 features of acute limb ischaemia? What 2 important features are important to gather in a history for people at risk of acute limb ischaemia?

Answer 32

1) pain (due to lack of blood supply to nerves) 2) pallor 3) pulseless 4) perishingly cold 5) paraesthesia = pins & needles/altered sensation 6) paralysis - no prior history of claudication - known cause for embolism

Question 33

describe the pain suffered in acute limb iscahemia.

Answer 33

- severe, sudden onset, resistant to analgesia

Question 34

what happens with the calf muscles in acute limb ischaemia?

Answer 34

- calf/muscles tenderness with tight compartment indicates muscle necrosis often irreversible iscahemia

Question 35

describe the pallor of the limb involved in acute limb ischaemia.

Answer 35

Initially = limb white with empty veins Later = capillaries fill with stagnated de-oxygenated blood giving a mottled appearance - Arteries distal to occlusion fill with propagated thrombus with rupture of capillaries

Question 36

is blanching mottling salvageable? is non-blachnig mottling reversible?

Answer 36

yes - if prompt re-vascualrisation no - it is irreversible ischaemia

Question 37

why does paraesthesia/parlysis occur in acute limb ischaemia?

Answer 37

- sensorimotor deficit are indicative of muscle & nerve ischaemia

Question 38

what time feature is acute limb iscahemia salvable?

Answer 38

0-4hours - white foot - painful - sensorimotor deficit

Question 39

what time feature is acute limb iscahemia partially reversible?

Answer 39

4-12hours - mottled - blanches on pressure

Question 40

what time feature is acute limb iscahemia non-salvageable?

Answer 40

>12hours - fixed mottling - non-blanching - compartments render/red - paralysis

Question 41

how do you manage acute limb ischaemia?

Answer 41

1) ABC – resuscitate and investigate 2) FBC, U/Es, CK, Coag +/- Troponin 3) ECG – MI, dysrhythmia 4) CXR – underlying malignancy 5) anti-coagulants = stops propagation of thrombus - may improve perfusion 6) arterial imaging

Question 42

if limb is salvageable, what do you do?

Answer 42

= embolectomy +/- fascioteomies +/- thrombolysis

Question 43

what 3 things does diabetic foot sepsis encompass?

Answer 43

1) diabetic neuropathy 2) peripheral vascular disease 3) infection

Question 44

what does this triad in diabetic foot sepsis lead to?

Answer 44

- tissue ulceration - necrosis - gangrene

Question 45

what causes diabetic foot sepsis?

Answer 45

- simple puncture wound - infection from nail plate or inter-digital space - from neuro-iscahemic ulcer (occurs on areas of increased pressure)

Question 46

why is diabetic foot sepsis a problem?

Answer 46

= within the foot the intrinsic muscles of digits are confine within rigid compartments - bounded by planter fascia, metatarsal bones and interosseous fascia - infection tracks in soft tissues into this rigid compartment

Question 47

what happens if the build up of pus cannot escape?

Answer 47

- pressure builds up in rigid compartment leading to impairment of capillary blood flow & further iscahemia & further tissue damage = can rapidly progress to sepsis & limb loss

Question 48

what 5 systemic things happen as a result of diabetic foot sepsis?

Answer 48

- pyrexia - tachycardia - tachypnoeic - confused - kussmauls breathing

Question 49

what 7 local features happens as a result of diabetic foot sepsis?

Answer 49

- swollen affected foot - swollen forefoot - tenderness - ulcer with pus extruding - erythema, may track up limb - patches of developing necrosis - crepitus in soft tissue of foot - pedal pulse may or may not be present

Question 50

how would you manage diabetic foot sepsis?

Answer 50

1) antibiotics - gram +ve cocci (S. aureus + streptococcus sp) - gram -ve bacilli (E. coli, klebsiella sp, enterobacter, proteus sp and pseudomonas sp.) - anaerobes (bacteroides) 2) rapid surgical debridement of infected tissue 3) remove all infected tissue 4) wound open to encourage drainage