Histo: Cerebrovascular disease and Trauma Flashcards
What are the two types of cerebral oedema?
- Vasogenic - due to disruption of blood-brain barrier
- Cytotoxic - secondary to cellular injury (e.g. hypoxia, ischaemia). This is usually due to damage to astrocyte end feet
Which water transporting molecule is found in the brain?
Aquaporin 4
What radiological appearance is characteristic of cerebral oedema?
Loss of gyri
Describe the passage of CSF through the brain.
- The choroid plexus (mainly found in the lateral ventricles) pumps out CSF
- It passes from the lateral ventricles, through the interventricular foramina and into the 3rd ventricle
- It then goes down the cerebral aqueduct into the 4th ventricle
- It then flows down into the medulla and down the spinal cord in the central canal of the spinal cord
- Most of the CSF will leave the 4th ventricle and enter the subarachnoid space
- CSF will circulate around the subarachnoid space and will drain via arachnoid granulations into the superior sagittal sinus (and hence back into the systemic circulation)
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What constitutes the floor and the roof of the 4th ventricle?
Floor = pons
Roof = cerebellum
Name and describe the two types of hydrocephalus.
- Non-communicating - caused by obstruction of CSF flow (usually in the cerebral aqueduct)
- Communicating - caused by reduced reabsorption of CSF into the venous sinuses (this could be caused by infection (e.g. meningitis))
What is the normal range for ICP?
7 - 15 mmHg
Name and describe the three sites of brain herniation.
- Subfalcine - the cortex is pushed under the falx cerebri
- Transtentorial (uncal) - the posterior cranial fossa is covered by the tentorium cerebelli which has a rigid opening for the brainstem. Supratentorial pressure can result in herniation of the medial temporal love over the rigid end of the opening of the tentorium cerebelli
- Tonsillar - herniation of the cerebellar tonsils through the foramen magnum (this can put pressure on the medulla and kill)
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Define stroke.
A clinical syndrome characterised by rapidly developing clinical symptoms and/or signs of focal or global loss of cerebral function with symptoms lasting > 24 hours or leading to death with no apparent cause other than that of vascular origin
Which diseases are encompassed by the term ‘stroke’?
- Cerebral infarction
- Primary intracerebral haemorrhage
- Intraventricular haemorrhage
- Subarachnoid haemorrhage (most of the time)
Which diseases are excluded by this definition of ‘stroke’?
- Subdural and epidural haemorrhage
- Infarction due to infection or tumour
What is a TIA?
Same definition as stroke but resolving within 24 hours
NOTE: TIA is an important predictor of future infarct (1/3 people with TIA will have a significant infarct within 5 years)
What is non-traumatic intraparenchymal haemorrhage?
Haemorrhage into the substance of the brain (parenchyma) due to rupture of small intraparenchymal vessels
Where do non-traumatic intraparenchymal haermorrhages tend to occur most frequently?
Basal ganglia
NOTE: hypertension is implicated in > 50% of bleeds
What is an arteriovenous malformation?
- A malformation where blood bypasses quickly from artery to vein without going through a normal capillary network
- They can occur anywhere in the CNS and they can rupture
- As they occur under high pressure, they tend to cause massive bleeds
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