Lecture 13 Flashcards
(69 cards)
what are some Diseases types in the Nervous System?
- Cerebrovascular diseases
- Nerve damage
- Neurodegenerative diseases
What are the main components of the nervous system (NS) parenchyma and support cells?
Parenchyma = neurons; Support cells = glia.
What is cerebral blood flow (CBF) in terms of brain tissue?
CBF is 45-55 ml per 100 g of brain tissue per minute.
What is cerebral autoregulation, and what mechanisms does it involve?
Autoregulation maintains stable CBF within a wide MAP range using metabolic and myogenic mechanisms.
What are the two types of cerebrovascular accidents (strokes) and their prevalence?
Ischaemic (80-85%) and Haemorrhagic (15-20%).
How long can neurons survive without oxygen (hypoxia) before cell death occurs?
Neuronal death occurs after 5-7 minutes of hypoxia.
What is the prevalence of strokes in Australia?
Stroke is the third most common cause of death in Australia, with about 55,000 Australians having a stroke annually, 73% of which are first-ever strokes.
What is the survival and recovery rate of stroke patients in Australia?
Of 100 stroke patients:
- About 30 will die within the first year.
- About 70 will survive, with 35 remaining permanently disabled after one year, 10 of whom may need long-term care.
- Around 35 may recover independence, with 25 still unable to perform all previous activities but able to live independently.
What percentage of stroke patients have ischaemic vs haemorrhagic strokes?
85% have ischaemic strokes, and 50% of haemorrhagic strokes lead to survival.
What is the Circle of Willis?
The Circle of Willis is a circulatory anastomosis that supplies blood to the brain and surrounding structures.
How does the cerebral blood supply affect clinical outcomes after a stroke?
The vessel affected in a stroke determines the area of brain damage, which leads to varied clinical effects based on the specific cerebral region impacted.
What is an ischaemic thrombotic stroke?
A stroke often involving the carotid distribution rather than vertebrobasilar, typically preceded by transient ischaemic attacks (TIAs) and may occur during mild blood pressure depression.
What is a TIA?
Transient Ischaemic Attack, also known as a “mini-stroke,” which is a temporary period of ischaemia without permanent damage.
What is an ischaemic embolic stroke?
A stroke that often involves the middle cerebral artery and leads to global ischaemia due to an embolus blocking blood flow.
What areas are commonly affected by an intracerebral haemorrhage?
Basal ganglia, thalamus, cerebellum, and pons (in that order).
What is a subarachnoid haemorrhage?
A type of haemorrhagic stroke often related to an aneurysm, which increases intracranial pressure (ICP) and causes bleeding in the subarachnoid space.
What are the main types of cerebrovascular accidents and their associated percentages?
Cerebral infarction (80%), Intracerebral haemorrhage (15%), and Subarachnoid haemorrhage (3%).
What is the clinical presentation and 30-day mortality rate for a cerebral infarction?
Slow evolving symptoms with a 15-45% 30-day mortality rate.
What are the causes and risk factors for cerebral infarction?
Causes include thrombus, embolism, and atheroma. Risk factors include heart disease, hypertension, atheroma, and diabetes.
Describe the pathogenesis of subarachnoid haemorrhage.
Rupture of a saccular aneurysm (often in the circle of Willis) can lead to subarachnoid haemorrhage, sometimes accompanied by a vascular spasm.
What is the classic triad of symptoms for meningism?
Neck stiffness, photophobia, and headache.
What are some key risk factors for cerebrovascular accidents?
Hypertension, atrial fibrillation, diabetes, and smoking.
Describe the process of cerebral infarction.
- 24 hrs after: Local softening and oedema.
-4 days after: Liquefactive necrosis, macrophage infiltration, and reactive astrocytes at the periphery.
- Final stage: Phagocytosis of necrotic tissue with cystic cavitation.
What is the pathogenesis summary for cerebrovascular accidents?
“THE SCAR OF Vessels”
T - Thrombosis: Arterial thrombosis due to atheroma in intracranial or extracranial arteries.
H - Head Injury: May lead to cerebral ischaemia, vascular occlusion, or rupture.
E - Embolism: Embolic arterial occlusion from atheroma in extracranial vessels.
S - Subarachnoid Haemorrhage: Rupture of a saccular aneurysm causing vascular spasm.
C - Critical Blood Flow Reduction: Reduction in cerebral blood flow (e.g., cardiac arrest).
A - Arterial Disease: Generalized arterial disease (e.g., vasculitis) affecting vessels.
R - Respiratory Arrest: Critical reduction in arterial oxygenation due to hypoxia.
O - Oral Contraceptives: Venous thrombosis due to local sepsis or drug effects (e.g., oral contraceptives).
V - Vasculitis: Generalized arterial disease affecting both intracranial and extracranial vessels.
