Neuropathology of brain vascular disease Flashcards
What are the 2 types of stroke
infarct and haemorraghic
what are the different types of hemorrhagic strokes and their causes? what are the causes of ischameic stroke?
Intracerebral Hemorrhage: The most common type of hemorrhagic stroke, occurring when an artery in the brain bursts, flooding the surrounding tissue with blood. Causes include high blood pressure (which weakens arterial walls over time), trauma and vascular malformations
Subarachnoid Hemorrhage: This type occurs when there is bleeding in the subarachnoid space — the area between the brain and the tissues covering it. It’s often caused by the rupture of an aneurysm (a weakened and bulged section of a blood vessel). Other causes might include arteriovenous malformations (AVMs), traumatic injury.
ishcaemic: Thrombosis: The formation of a blood clot within a blood vessel in the brain, which can be due to atherosclerosis (plaque buildup) narrowing the arteries.
Embolism: A blood clot or other debris circulating in the blood lodges in a blood vessel and blocks it. This often originates in the heart and is known as a cerebral embolism. Conditions like atrial fibrillation (an irregular heartbeat) can increase the risk, it does this as the upper chambers of heart contract irregularly, it can lead to a blood pool due to distrupted blood flow and makes it more easy for blood clots to form.
what is the definition of stroke
condition where there is lack of perfusion of oxygenated blood to cerebral areas that can lead to damage and in severe cases necrosis
what is an atheroma and what are the causes?
An atheroma, or atherosclerotic plaque, is a buildup of fatty materials such as cholesterol, fatty substances (a clotting material in the blood) inside the walls of arteries.
restricting blood flow and reducing oxygen supply to the tissues and organs that the arteries serve.
caused by high blood pressure, smoking, diabetes, high cholesterol, hyperlipidaemia
how does a thrombus lead to damage? and what are the 3 layers of a blood vessel?
-Damage to endothelium, the inner lining of blood vessel lumen.
-platelets forming on that damaged area causing blood clot whereby fibrinogen gets converted to fibrin
-narrowing or complete occlusion of vessel
The blood vessels have three layers (Inner most layer-tunica intima, medial layer-tunica media, outer layer- tunica adventitia)
Atheroma is a disease of the intima (Innermost layer)- that’s why you get damage to lining of blood vessel-endothelium (which tells blood to not clot) therefore damaging it, will cause it to clot as its damaged
what are the consequences of thrombosis?
It won’t stay as a group of platelets and a mesh of fibrin-it will get converted into fibrous tissue in a few months. So, it will become fibrous tissue as part of the tissue body and its useless. this weakens the blood vessel over time. And so, if its narrowed enough and other blood supply isn’t sufficient it can cause neurological symptoms such as loss of conciousness, one sided lack of movement.
In embolus- you got that clot already formed and part of it gets pushed by blood coming through onto other blood vessels in the system
if there are occlusions in coronary artery, what can this lead to? and what can be used for this, what medications?
myocardial infarction/heart attack
Blood thinners may not work in the fully occluded one- cardiac bypass might be better (stop you heart temporarily switching to a heart-lung machine to pump blood around body.
thrombectomy can also be used.
fibrinolytic therpay may also be useful to dissolve the clots and restoring adequate blood flow
what is cerebral amyloid angiopathy?
Rare
Causes it in white matter, accumulatio of abnormal amyloid protein- beta amyloid is commonest- associate with AD
This is a condition associated with the accumulation of amyloid protein within the walls of the cerebral arteries, leading to their weakening
what does a space occupying lesion cause?
it is when there is growth or mass within a space inside the body thatc an press on surrounding tissue or organs. in the context of the brain, it can be like haeorrhage(bleed), tumour, a cysts.
leads to increased pressure insde the skull, causing problems such as headaches, vision problems, nausea.
some csf can be remved to remove the swelling because the heamorrhage would put pressure on certain areas of the brain.
what are some of the methods that help view occlusions within the vascular anatomy of the brain?
Angiogram/angiography
-Computed Tomography Angiography (CTA): This is a type of CT scan that uses a contrast material injected into a blood vessel to provide detailed images of the blood vessels in the brain. CTA can quickly identify blockages or other vascular abnormalities.
-Magnetic Resonance Angiography (MRA): MRA uses magnetic fields and radio waves to generate detailed images of the blood vessels without the need for X-rays. Like CTA, it can also use a contrast agent to improve the clarity of the images, making it useful for detecting blockages.
-Digital Subtraction Angiography (DSA): DSA is a type of fluoroscopy technique where images are taken before and after injecting a contrast agent into an artery. The before images are subtracted from the after images, removing the background and highlighting the blood vessels. DSA is considered the gold standard for imaging blood vessels in the brain because it provides very detailed images of the blood flow and identifies blockages or other issues.
what converts fibrinogen to fibrin and what converts plasminogen to plasmin
thrombin converts fibrinogen to fibrin, which helps form a mesh-like structure trapping blood cells, especially platelets, to stabilise the blood clot. this is part of the process known as thrombosis.
The tissue plasminogen activator converts plasminogen to plasmin, which breaks down fibrin into small fragments known as D-dimers. this is part of the process known as fibrinolysis
