13 Aneurysmal Diseases Flashcards
remarks on aneurysms
an aneurysm is dilation of the arterial wall to >1.5 times its normal diameter
the wall of a true aneurysm involves all layers of the vessel
rupture is catastrophic, occurring once the stress on the vessel wall exceeds its tensile strength
Laplace law
wall tension = pressure x radius
remarks on pseudoaneurysms
the wall of a pseudoaneurysm consists partly of the vessel wall and partly of fibrous or other surrounding tissue
a pseudoaneurysm can develop at the site of previous vessel Catheterization and at anastomoses from prior vascular Reconstruction, Infection, or Trauma
small pseudoaneurysms may eventually spontaneously thrombose
remarks on mycotic aneurysms vs infected aneurysms
MYCOTIC ANEURYSMS occur secondary to a septic embolization from valvular endocarditis
whereas INFECTED ANEURYSMS develop in an existing aneurysm after bacteremia or direct extension from a neighboring infection
most common peripheral aneurysm
popliteal aneurysm
- they often coexist with contralateral popliteal aneurysms or abdominal aortic aneurysms
visceral artery aneurysms are most common in
renal, splenic, and hepatic arteries
all but splenic artery aneurysms are more common in elderly men.
mortality rate of aneurysmal rupture
80% mortality rate
remarks on abdominal aortic aneurysm
an abdominal aortic aneurysm is defined as an aorta ≥3.0 cm in diameter
repair is considered for an aneurysm ≥5.0 cm in diameter
most patients are >60 years old
most important environmental risk factor for abdominal aortic aneurysm
smoking
in addition, smoking is a major risk factor for accelerated aneurysmal growth and rupture
most common presenting symptom with aortic aneurysm or rupture
BACK or ABDOMINAL PAIN
pain is classically severe and abrupt in onset, with about half of patients describing a ripping or tearing pain.
classic triad of ruptured abdominal aortic aneurysm
abdominal pain
pulsatile abdominal mass
hypotension
occurs in only 1/3 of patients
other manifestations of symptomatic abdominal aortic aneurysms
GI bleeding (from an aortoenteric fistula)
Extremity ischemia (from embolization of a thrombus in the aneurysm)
Shock
Sudden death
consider an aortic aneurysm rupture in
a patient with abrupt back pain with syncope or shock
iliopsoas sign
pain upon extension of the hip, typically with the patient lying on the opposite side
due to irritation of the psoas muscle from retroperitoneal blood
remarks on abdominal aortic aneurysm and femoral artery
the presence or rupture of an abdominal aortic aneurysm typically does not alter femoral arterial pulsations
aortoenteric fistulas most frequently involve what part of the GI tract?
duodenum
imaging modality of choice for unstable ΑAA patients
bedside US
- a technically adequate US study has >90% sensitivity for demonstrating the presence of an aneurysm and measuring its diameter
- identifying the superior mesenteric artery allows distinguishing the aorta from the vena cava
radiographs in aortic aneurysms
65% of patients with symptomatic aortic aneurysm disease have a calcified aorta, which may be more obvious on a lateral view
Plain film radiographs do not exclude the presence of abdominal aortic aneurysm or detect rupture and should be omitted for most patients
an aortic diameter ________ excludes acute aneurysm disease
<3.0 cm
best detects the anatomic details of the aneurysm and associated hemorrhage
CT scan with IV contrast
Scan all stable patients with suspected abdominal aneurysm disease or rupture.
For those who cannot have IV contrast, unenhanced CT can reveal aneurysm size and retroperitoneal hemorrhage
ED interventions for symptomatic ΑAA
- IV access
- Consultation (as soon as the diagnosis is suspected)
- Blood and fluids *(targets unclear; permissive hypotension SBP 80-90 mm Hg with intact mentation is recommended)
- Pain control
this can be given in the event of suspected expanding aneurysm and severe hypertension
esmolol, for its ability to be titrated to a target SBP of 120 mm Hg.
esmolol can be quickly stopped if the patient’s BP drops suddently.
other remarks on aortic aneurysms
- symptomatic aneurysms of any size are considered emergent.
- All asymptomatic aortic aneurysms should be referred for follow-up.
- ΑAA in women have a greater likelihood of rupture than in men, often at smaller sizes.
remarks on popliteal artery aneurysm
>2 cm or >150% of normal caliber
may present with claudication
rupture is rare
sudden acute limb ischemia caused by thrombosis or embolization from the aneurysm is the most serious common complication
nonaortic aneurysm where female sex is a risk factor
splenic artery aneurysm
- rupture has a poor prognosis because of its intraperitoneal location and nondescript presentation
- be wary of these in the third trimester of pregnancy
remarks on hepatic artery aneurysm
Quincke’s triad
Hematemesis (UGIB)
Biliary colic
Jaundice
- seen when hemobilia (bleeding into biliary tract) from a leaking hepatic artery aneurysm occurs
classic presentation of aortoenteric fistula from anastomotic aneurysms
severe lower GI bleeding in a patient with a history of ΑAA repair
management of peripheral artery aneurysms
initial diagnostic: doppler US
if ischemia and thrombosis exist, emergent CT angiography
for patients with clinical extremity ischemia, consult immediately with a vascular surgeon to expedite repair and limb salvage
asymptomatic peripheral aneurysms are managed by a vascular consultant as an outpatient
management of mycotic and infected aneurysms
these require appropriate IV antibiotics, often for prolonged periods
and consultation for surgical repair
(emergent consultation should be sought for suspected rupture)
