WEEK 2 ANEURYSMS and HAEMORRHAGIC STROKE Flashcards
What is an anuerysm?
- A bulging weak area in the wall of an artery
Can aneurysms occur anywhere throughout the vascular system?
Yes BUT they most commonly develop along the aorta and in the blood vessels of the brain.
How long can death occur within if the aneuryms rupture?
- Within minutes
What are 5 potential causes of aneurysms?
- Weakness in the blood vessel wall that is present from birth (congenital aneurysm)
- High blood pressure (hypertension)- the hihg blood pressure leads to weakening
- Past aneurysm will increase the likelihood of another (can be genetic predisposition)
- Race–> African Americans are more likely than Caucasians to have subarachnoid hemorrhage (genetic factor but no science to back up why)
- Fatty plaques (atherosclerosis) resulting in the weakening of the blood vessel wall
Are women more likely to develop a brain aneurysm or suffer a subarachnoid hemorrhage than men?
- Yes
- Could be due to a drop in estrogen post menopausal
- Estrogen may act as a cardiovascular protector
Why can having polycystic kidney disease result in an increased risk of cerebral aneurysm?
- Autosomal dominant inheritance
- The genes that contribute to this disease are disrupted and may also play an important role in blood vessels
- So without them, there could be a dtysfunction
What are the three main locations for an aneurysm?
- Cerebral aneurysm
- Thoracic aortic aneurysm
- Abdominal aortic aneurysm
What percentage of strokes do cerebral aneurysms make up?
15% of all strokes.
- The Strokes are hemorrhagic.
Can an unruptured cerebral aneurysm have symptoms?
- No symptoms are present and because of this it can be discovered incidentally.
What are the symptoms of a ruptured cerebral aneurysm?
- Severe headache with rapid onset
- Neck pain and stiffness.
- Increasing drowsiness.
- Paralysis
- Seizures
- Impaired speech and visual problems.
- Sensitivity to light
In terms of cerebral aneurysms, what is the most common type of aneurysm that accounts for 80 and 90% of all intracranial aneurysms?
- Saccular aneurysm
Which age are brain aneurysms most prevalent in?
- 35-60 BUT can occur at any age
What percentage of ruptured brain aneurysms result in death?
- 40% of cases.
- Those who survive about 66% suffer some permanent neurological deficit.
Roberts image of patients with aneurysmal subarachnoid haemorrhage die before reaching the hospital?
- 15%
Are the names of the types of cerebral aneurysms the same for the aortic aneurysms?
- YES
- These are saccular, fusiform, giant and dissecting
What is the most common type of aneurysms for Cerebral aneurysms?
- A saccular aneurysm. (shape)
What is the most common type of aneurysm for aortic aneurysms?
- Fusiform aneurysm
What are the four main types of aneurysms?
- Saccular
- Fusiform
- Giant
- Dissecting
What’s another name for the saccular aneurysm?
- The Berry aneurysm.
- This is because it has rounded lobulated focal outpouchings which usually arrise at the arterial bifurcations and can arise from the lateral wall.
What characterizes a fusiform aneurysm?
- An out-pouching of an arterial wall on both sides of the artery.
Does the fusiform aneurysm have a neck or stem?
- No
What classifies a giant aneurysm?
Aneurysm that are larger than 2.5 cm.
- It can be hard to treat. They also high-risk.
What percentage of aneurysms do NOT rupture during the course in a person’s lifetime?
- 50 to 80%.
What is a dissecting aneurysm?
- Bleeding into a weakened artery wall splits the wall
- This leads to the artery wall ripping
- This then creates a false lumen that the blood flows into
Is a dissecting aneurysm the most damaging type of aneurysm?
- YES
What can be used to try and fix the artery wall in a dissecting aneurysm?
- Putting stents in and coils
What are the symptoms of an abdominal aneurysm?
- Excruciating abdominal pain
- Pain going towards the back
- Drop in blood pressure
If an abdominal aortic aneurysm ruptures, what is the associated mortality?
- 80%
How can an abdominal aortic aneurysm be fixed?
-Can be fixed with surgery BUT 50% mortality if already ruptured
What is associated with a lower mortality with abdominal aortic aneurysm?
- Screening men over 65 yrs
What is the treatment when you have a small aortic aneurysm?
- Ultrasound surveillence and risk factor modification
What are some things to consider when deciding whether or not to treat an unruptured aneurysm?
- The risk of hemorrhage
- Size and location
- Age of the patient (i.e. if you’re 90 vs. if you’re 30)
- Family history
- Surgery risks
What are the two potential treatments for an unruptured aneurysm?
- Surgical clipping
- Endovascular coiling
What is involved in surgical clipping of an unruptured aneurysm and is it high risk?
- This is a very high risk procedure because it is INVASIVE
- Part of the skull must be removed and clips the blood vessel that goes to the aneurysm to STOP blood flow to it
What is involved in endovascular coiling to treat an unruptured aneurysm and is it high risk?
- Placing a stent into the blood vessel
- Then a coil is placed in and is supposed to strengthen and FILL the aneurysm so that it is LES LIKELY to rupture
- This is VERY EFFECTIVE
- Less high risk than clipping
What are pharmacological treatments for hemorrhagic stroke?
- Osmotic agents –> used to reduce edema, intracranial pressure following haemorrhagic stroke
What is the use of mannitol in treating hemorrhagic stroke?
- It raises the serum osmolarity within the vasculature
- Plamsa osmotic pressure is increased relative to the CSF
- Causes an increase in osmotic pressure in the serum and water flows from the tissue into the blood
- NOT very effective
What are the adverse effects of Mannitol to treat hemorrhagic stroke?
- 10% of patients will develop edema
- Because mannitol could leak back into the tissue from the vessles because the BBB can become leaky
- VERY dangerous depending on the site in the brain
What are the three types of surgical treatment for hemorrhagic stroke/ ruptured aneurysm?
- Surgical clipping
- Endovascular coiling
- Surgical repair (aortic aneurysm)
Why do you need multiple stroke animal models?
- Because stroke in humans in heterogeneous with complex pathophysiologies
- If you choose the most appropriate stroke model, you can increase the transnational potential
What kinds of animal models do the ischaemic stroke models include?
- Middle cerebral artery occlusion
- Photothrombotic stroke
- Endoothelin-1 stroke
- Embolic stroke
What kinds of stroke models do haemorrhagic stroke models include?
- Autologous blood injection
- t-A induced stroke
- Endovascular puncture
What type of model is the middle cerebral artery (MCA) occlusion for stroke?
- Severe model
- Mouse can’t feed after.
What are the pros of MCA occlusion for ischameic stroke models?
- Mimics human stroke bc occluding the middle cerebral artery
- Reperfusion and duration can be controlled via laser doppler
- Blood flow is measured
- Most common model
What are the downsides of MCA animal model for ischaemic stroke?
- Variable infarct damage
- Invasive as you are nicking the neck which means increased risk of internal bleeding
What are the pros of photothrombotic ischaemic stroke model?
- Induces thrombus
- Minimal surgical intervention
- Highly reproducible infarct damage
What are the cons of photothrombotic ischaemic stroke model?
- Little or NO ischaemic penumbra (outer region of infarct)
- Can’t measure blood flow
How does the photothrombotic ischaemic stroke model work?
- A photosensitive dye given
- forms clots when exposed to light
- This leads to free radical formation, platelet aggregation and ROS –> inflammation, more clots, causing the stroke
- NATURAL CLOTS FORM LIKE IN HUMANS
What are the pros of the endothelin model for ischaemic stroke in mice?
- The mice are conscious –> because the day before moues has surgery where catheter put in MCA and next day endothelin (POTENT VASOCONSTRICTER) is injected
- Low mortality
- Reproducible infarct damage
What are the cons of endothelin model for ischaemic stroke in mice?
- Induces astrocytes nd facilitates axonal sprouting
- Can’t measure blood flow changes
- Lacks the BBB breakdown
What are the two models for hemorrhagic stroke?
- Autologous blood injection model.
2. Endovascular puncture model.
What are the pros of the autologous blood injection model for hemorrhagic stroke?
- Blood is injected into the striatum to establish a haematoma
- Widely used model.
- Good reproducibility and relevant to ICH (intracerebral haemorrhage) patients.
What are the cons of the autologous blood injection model for hemorrhagic stroke?
- Doesn’t simulate blood vessel rupture
What are the pros for the endovascular puncture model for hemorrhagic stroke ?
- Closely mimics SAH (sub arrachnoid haemorrhage) in the clinic
- Blodd flow can be measured
What are the cons of the endovascular puncture model for hemorrhagic stroke?
- Invasive surgery
