Aneurysms & Vasculitides Flashcards
(69 cards)
What are aneurysms?
Abnormally dilated part of a vessel or the heart.
What causes aneurysms?
Congenital or acquired weakness in tunica media of the vessel (or the myocardium)
Where do aneurysms typically occur?
Usually in arteries or left ventricle
What are true and false aneurysms?
True aneurysm is an aneurysm in which the entire tissue is enlarged outward.
False anerysm is an aneurysm in which there is a hole in the vascular wall and leakage of blood to the outside
How are aneurysms calssified?
Cause (congenital, mycotic, inflammatory, traumatic arterial injury)
Morphology (Sacular, bubble-like outpouching or fusiform)
Anatomical site (Aortic, Iliac, Left ventricular, Popliteal, etc)
What type of aneurysms are typically seen in the abdominal aorta?
Fusiform
Where are berry aneurysms typically seen?
Circle of willis
What are the complications associated with aneurysms?
Rupture can lead to rapid loss of blood or sub-arachnoid haemorrhage
Occlusion can disturb the bloodflow in the vessel and can lead to thrombus formation which can occlude the involved vessel or one of its branches.
Mass effect which is the compression of surrounding structures like a tumour
What are cerebral saccular aneurysms?
Commonly called berry aneurysms. They are located at branch points of the large intracranial arteries in the circle of willis
Why do berry aneurysms form?
Weakened areas where they occur are caused by congenital defects in the smooth muscle layer of the artery (tunica media)
THE ANEURYSM ITSELF IS NOT CONGENITAL
What conditions cause increase risk in aneurysm formation?
Polycystic kidney disease and Ehlers-Danlos syndrome (conditions of the connective tissue)
Haemodynamic stress conditions such as hypertension and smoking cause aneurysm to expand over time.
Why is smoking a risk factor for aneurysms?
It damages arterial walls
What are complications of berry aneurysms?
Mass effects which cause compression of adjacent brain and cranial nerves which clinically leads to headaches, double vision, and loss of vision
Rupture can cause subarachnoid haemorrhage
What are the clinical features of berry aneurysms?
Before rupture:
Usually asymptomatic
Sentinel headache which can be severe
Vomiting, double vision, seizures (mass effect)
Rupture and subarachnoid haemorrhage: Thunderclap headache Vomiting, collapse, confusion, seizures Approx 25% die within 24 hours Further 25% die within 3 months Of the survivors 50% have permanent neurological defects
How are berry aneurysms diagnosed?
MRI
CT scan
Angiogram
CSF analysis showing blood (=ggwpscrub)
When do aortic aneurysms occur?
Abnormality in tunica media -> destroys capacity of tissue to resist the haemodynamic forces of systole
What processes cause abnormalities in aortic tunica media?
Atherosclerosis
Non-inflammatory degeneration
Inflammation eg. syphilis, giant cell aortitis
Where on the aorta are aortic aneurysms most common?
Below the level of the renal arteries and above aortic bifurcation
Which people get AAA most often?
Caucasian, male, elderly
Risk factors include: Smokers, alcohol drinkers, hypertensive people and some genetic markers
Atherosclerosis causing medial atrophy
What are the possible complications of AAA?
Rupture causing large volume of blood under high pressure to escape into peritoneal cavity or the retroperitoneal tissues resulting in mass haemorrhage.
Peripheral thromboembolism causing occlusion of distal arteries
What are the clinical features of AAA?
Before rupture: Usually asymptomatic, can feel back pain, abdominal pain, and a throbbing sensation
Rupture: results in a triad of abdominal pain, hypovolaemic shock and a pulsatile abdominal mass.
How does aortic aneurysm rupture present itself?
Pain is sudden onset, excrutiating and is felt in the abdomen, flank or groin
How can AAA be diagnosed?
Clinical findings or imaging studies
What is the mortality rate of AAA?
90% mortality associated with AAA rupture
