Histo: Cerebrovascular disease and Trauma Flashcards

1
Q

What are the two types of cerebral oedema?

A
  • 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
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2
Q

Which water transporting molecule is found in the brain?

A

Aquaporin 4

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3
Q

What radiological appearance is characteristic of cerebral oedema?

A

Loss of gyri

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4
Q

Describe the passage of CSF through the brain.

A
  • 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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5
Q

What constitutes the floor and the roof of the 4th ventricle?

A

Floor = pons

Roof = cerebellum

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6
Q

Name and describe the two types of hydrocephalus.

A
  • 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))
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7
Q

What is the normal range for ICP?

A

7 - 15 mmHg

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8
Q

Name and describe the three sites of brain herniation.

A
  • 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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9
Q

Define stroke.

A

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

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10
Q

Which diseases are encompassed by the term ‘stroke’?

A
  • Cerebral infarction
  • Primary intracerebral haemorrhage
  • Intraventricular haemorrhage
  • Subarachnoid haemorrhage (most of the time)
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11
Q

Which diseases are excluded by this definition of ‘stroke’?

A
  • Subdural and epidural haemorrhage
  • Infarction due to infection or tumour
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12
Q

What is a TIA?

A

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)

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13
Q

What is non-traumatic intraparenchymal haemorrhage?

A

Haemorrhage into the substance of the brain (parenchyma) due to rupture of small intraparenchymal vessels

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14
Q

Where do non-traumatic intraparenchymal haermorrhages tend to occur most frequently?

A

Basal ganglia

NOTE: hypertension is implicated in > 50% of bleeds

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15
Q

What is an arteriovenous malformation?

A
  • 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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16
Q

How are arteriovenous malformations treated?

A
  • Surgery
  • Embolisation
  • Radiosurgery
17
Q

Define cavernous angioma.

A
  • Well-defined malformative lesion composed of closely-packed vessels with no parenchyma interposed between vascular spaces
  • NOTE: it is similar to an arteriovenous malformation but there is no brain substance wrapped up amongst the vessels
  • NOTE: these tend to bleed at lower pressure causing recurrent small bleeds
18
Q

Describe the appearance of cavernous angiomas on MRI.

A

Shows target sign

19
Q

What causes subarachnoid haemorrhages?

A

Rupture of a berry aneurysm

NOTE: berry aneurysms are congenital

20
Q

Where are berry aneurysms typically found?

A
  • 80% at the internal carotid bifurcation
  • 20% within the vertebro-basillar circulation
  • NOTE: highest risk of rupture if diameter of 6-10 mm
21
Q

What is the most common cause of cerebral infarctions?

A

Cerebral atherosclerosis

22
Q

Where is atherosclerosis most commonly found within the cerebral vasculature?

A
  • Carotid bifurcation
  • Basilar artery
23
Q

Which part of the cerebral vascular tends to be affected by infarcts resulting from emboli?

A

Middle cerebral artery branches

24
Q

List some differences between infarctions and haemorrhagic strokes.

A

Infarction

  • Tissue necrosis
  • Rarely haemorrhagic
  • Permanent damage in the affected area
  • No recovery

Haemorrhage

  • Dissection of parenchyma
  • Fewer macrophages
  • Limited tissue damage
  • Partial recovery
25
Q

What is the biggest cause of death in people < 45 years?

A

Traumatic brain injury

26
Q

Describe how traumatic brain injury can be classified.

A
  • Non-missile and missile (e.g. shrapnel)
  • Acceleration and deceleration (e.g. RTA, includes rotational)
  • Focal or diffuse
27
Q

What are the consequences of base of skull fractures?

A
  • The fracture may pass through the middle ear or anterior cranial fossa
  • It can cause otorrhoea or rhinorrhoea
  • Increased risk of infection

NOTE: battle sign and raccoon eyes are manifestations of basal skull fractures

28
Q

With regards to brain injury, what is a laceration?

A

Bruising of the brain that causes rupture of the pia mater

29
Q

What is the term used to describe reboud injury to the opposite side of the brain?

A

Contrecoup injury

30
Q

What is diffuse axonal injury?

A
  • Occurs at the moment of injury
  • Shear and tensile forces causes damage to the axons
  • This is the most common non-bleed related cause of coma
  • Midline structure are particularly affect (e.g. corpus callosum)
  • Some people suffer cognitive and behavioural changes further down the line