case 14 - collapse Flashcards
What is the clinical name for a stroke?
Cerebrovascular Accident (CVA)
What is a cerebrovascular accident/stroke?
A clinical term referring to cerebrovascular disease, encompassing those that cause hypoxic iscahemia and haemorrhage
What differentiates a CVA from a TIA?
A CVA causes a rapidly developing focal or global lesion that lasts longer than 24 hours often with permanent neurological damage, while a TIA causes a deficit lasting less than 24 hours with complete recovery.
What are the 2 broad categories of stroke?
Ischaemic, Haemorrhagic
What are the 2 subtypes of ischemic stroke?
Global cerebral ischaemia, focal cerebral ischaemia
What is global cerebral ischaemia?
A generalised decrease in cerebral perfusion and hypoxia.
What are some of the causes of global cerebral ischaemia?
myocardial infarction, heart failure, cardiac arrest, shock/hypotension
What parts of the brain are most vulnerable to damage in global cerebral ischaemia?
‘Watershed areas’ - areas of the brain that lie at the border/distal part of different arterial perfusion areas.
What is focal cerebral ischaemia?
An obstruction of blood supply to a localised area of the brain for long enough to cause ischaemic infarction
Which vessel is most commonly involved in infarcts to large vessels of the brain?
The MCA - middle cerebral artery
Which areas of the brain are usually impacted by infarcts of small penetrating vessels?
Basal ganglia, thalamus, internal capsule
What is the name of an area of vulnerable tissue around an ischaemic area in a stroke?
The penumbra
What are the 2 classifications of ischaemic infarcts/strokes?
Haemorrhagic infarcts, non-haemorrhagic infarcts
What vascular event most commonly causes a haemorrhagic ischemic infarct?
An embolism - a thrombus that has travelled arterially from the periphery
What are some of the common causes of embolism that lead to haemorrhagic ischemic infarcts?
Mural thrombi in MI, stasis in AF/valvular disease, thormbosis overlying atherosclerotic plaques, paradoxical emboli from a DVT passing through a septal defect.
What is the gross appearance of a haemorrhagic ischemic infarct in the brain?
Multiple petechial haemorrhages and an area of redness
What causes the haemorrhage associated with embolic strokes?
Reperfusion of damaged tissue through collateral circulation or following thrombolysis of thromboembolic material and leakage of blood through necrotic vessels.
What is the mechanism of neuronal damage in haemorrhagic ischemic infarcts?
decreased perfusion/oxygen supply, cerebral oedema raises ICP, haemorrhage causes vasospasm and neurotoxicity
What vascular event typically causes a non-haemorrhagic ischaemic infarct?
A thrombotic event in the brain, such as plaque rupture
What type of arteries is typically involved in thrombotic events within the brain?
Medium sized arteries - most prone to plaque rupture
What is the gross appearance of non-haemorrhagic ischaemic infarcts in the brain?
A pale, bland appearance, followed later by blurring of the grey-white matter interface
What is the mechanism of neuronal damage in non-haemorrhagic ischaemic infarcts?
Lack of oxygen and nutrient supply
What are 2 most common types of haemorrhagic stroke?
Hypertensive intracranial bleeding, Subarachnoid haemorrhage
What is hypertensive intracranial bleeding?
A type of hameorrahgic stroke where chronic hypertension damages arteries and arterioles causing vessel rupture and intraparenchymal haemorrhage
What is the most common cause of spontaneous subarachnoid haemorrhage?
Rupture of a berry aneurysm in a cerebral artery
What are the symptoms of a spontaneous subarachnoid haemorrhage?
Thunderclap headache, signs of meningeal irritation (neck stiffness, photophobia, etc.)