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)

Result is raised ICP

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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 throught the lateral and median apertures
  • 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 - no obstruction, instead caused by increased production or 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

What are 2 common causes of raised ICP

A

Cerebral oedema

Space occupying lesion

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9
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 cause brain death)
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10
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

Key points
- rapid onset
- localised/ focal symptoms
- requires quick intervention

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11
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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12
Q

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

A
  • Subdural and epidural haemorrhage
  • Infarction or haemorrhage secondary to infection or tumour
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13
Q

What is a TIA?

A

Same definition as stroke but resolving within 24 hours (typically lasts less than 5 minutes)

Result of clot causing temporary blockage

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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14
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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15
Q

What is a big risk factor for non-traumatic haemorrhagic stroke

A

Hypertension (implicated in over 50% of bleeds)

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16
Q

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

A

Basal ganglia

17
Q

What are some common presenting clinical features of haemorrhagic stroke

A
  • Severe headache
  • Vomiting
  • Rapid loss of consciousness
  • Focal neurological signs
18
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
19
Q

How are AVMs diagnosed

A

Cerebral angiography

20
Q

How are arteriovenous malformations treated?

A
  • Surgery
  • Embolisation
  • Radiosurgery
21
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

22
Q

Describe the appearance of cavernous angiomas on MRI.

A

Shows target sign

23
Q

What causes subarachnoid haemorrhages?

A

Rupture of a berry aneurysm (present in 1% of population)

NOTE: berry aneurysms are congenital

24
Q

Where are berry aneurysms typically found?

A

Base of brain (circle of Willis)
* 80% at the internal carotid bifurcation
* 20% within the vertebro-basillar circulation

NOTE: highest risk of rupture if diameter of 6-10 mm

25
Q

What are the common presenting clinical features of SAH

A
  • Sudden onset (thunderclap) headache, vomiting, loss of consciousness
  • May also have symptoms of meningeal irritation (neck stiffness, photophobia)
  • Warning leak a few days to weeks prior causing transient severe headache
26
Q

How are cerebral aneursyms treated

A

Endovascular coiling

27
Q

What is the most common cause of cerebral infarctions?

A

Cerebral atherosclerosis

28
Q

Where is atherosclerosis most commonly found within the cerebral vasculature?

A

Extracranial
- Carotid bifurcation

Intracranial
- MCA
- Basilar artery
- Internal carotid

29
Q

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

A

Middle cerebral artery branches

30
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
31
Q

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

A

Trauma

32
Q

Describe how traumatic brain injury can be classified.

A

Non-missile and missile (e.g. shrapnel)

Acceleration/deceleration, rotational

Focal or diffuse

Causes: RTA, falls, assault

33
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 CSF otorrhoea or rhinorrhoea
  • Increased risk of infection
34
Q

What are some clinical signs of base of skull fractures

A

Battle sign
Raccoon eyes

35
Q

With regards to brain injury, what is a contusion and what is a laceration?

A

Contusion - collison of brain with skull causing surface bruising
Laceration - tearing of the pia mater

36
Q

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

A

Contrecoup injury

37
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
38
Q

What areas of the brain are commonly affected by diffuse axonal injury

A
  • Midline structures are particularly affected (e.g. corpus callosum, rostral brainstem, septum pellucidum)
  • Some people suffer cognitive and behavioural changes further down the line