CNS Pathology

Question 1

What are the different planes for imaging

Answer 1

Question 2

Why do we get raised intracranial pressure

Answer 2

Question 3

What is Herniation?

Answer 3

• Brain herniation occurs when something inside the skull produces pressure that moves brain tissues. This is most often the result of brain swelling or bleeding from a head injury, stroke, or brain tumor

Severe raised intracranial pressure can lead to this.

• Subfalcine (below flax cerebri -dural reflection in longitudinal fissure)
• Uncal – breaks through tentorium cerebelli
• Tonsillar -inferior region of cerebellum, herniation through cerebellar tonsils.

Question 4

What are the two types of stroke?

Answer 4

• Hemorrhagic stroke = weakened/diseases blood vessels rupture. Blood then leaks into bran tissue
• Ischaemic stroke = blood clots stop the blood to an area of the brin and ischaemia leads to tissue death (infarction).
• If it doesnt lead to infarction/tissue death it is a transient ischaemic attack
• Can eb caused by blood clot (thrombosis) that can block an artery (embolism)

Question 5

What are the meninges?

Answer 5

• Three layers of membranes known as meninges protect the brain and spinal cord.
• Dura mater
• Pia mater
• Arachnoid mater

Question 6

The circle of Willis - what is this?

Answer 6

• Dual arterial supply from the internal carotids and basilar artery

Question 7

The middle cerebral artery shcematic and clinical consequences if problem

Answer 7

Watershed locations are those border-zone regions in the brain supplied by the major cerebral arteries where blood supply is decreased.

MCA – exist circle willis and goes through sylvian (lateral) fissure and goes on to side of brain. Supplies all lobes of brain. Common impairments seen with middle cerebral artery (MCA) stroke include, but are not limited to, neglect, hemiparesis, ataxia, perceptual deficits, cognitive deficits, speech deficits, and visual disorders.

Question 8

Anterior and posteiror cerebral artery schematic

Answer 8

Patients with a PCA stroke may present with only a headache and mild visual changes such as vision loss, diplopia, inability to see half of the view, or difficulty reading perceiving colors, or recognizing familiar faces.

Distinctive symptoms in ACA territory infarction include altered mental status, abulia, mutism, decreased verbal fluency, aphasia, and urinary incontinence

Question 9

What does this image show?

Answer 9

Functional localisation in the cortex.

Question 10

The soamtosensory cortex

Answer 10

Question 11

The primary motor cortex

Answer 11

The density of cortical neurones that generate information is proportional tothe degree of control in the body.

Question 12

Blood supply to coornal section of the brain

Answer 12

Question 13

What are astrocytes?

Answer 13

• Astrocytes - population of cells with distinctive morphological and functional characteritics that differ within specific areas of the brain.
• They are a cell - type of neuroglia in NS.

Question 14

What are olgiodendrocytes

Answer 14

• Oligodendrocytes = myeliating glia of the CNS. Myelination of axons allows rapid saltatory conduction of nerve impulses and contirbutes to axonal integrity.

Question 15

What are microglial cells

Answer 15

• Microglial Cells - specialised population of macrphages found in CNS. Remvoe damaged neurons and infectiosn and important for maintaining health of CNS

Question 16

What is this?

Answer 16

• Liquefactive necrosis
• Brain tissue becones digested as a result of the action of microglia, creating a viscous liquid
• To be contrasted with gangrenous (limbs - no specific pattern), caseaous (cheeselike esp in lungs), fat necrosis (around pancreas/peritoneal cavity) and fibrinoid necrosis (blood vessels)
• Liquefactive necrosis – result of microglial cells (immune cells of the brain). Liquefactive necrosis is where rbain tissue becomes digested as a result of action of microglial, creating viscous liquid. As opposed to gangrenous, caseous etc necrosis.

Question 17

What does this image show ans the types?

Answer 17

• Haematoma - bleeding into spaces (Sub-arachnoid) or potential spaces (epidural subdural) Within meninges
• Epidural haeatoma - typically caused by skull fracture that perforate smeningeal artery.
• Subdural haematoma - typucall caised by soft tissue trauam that results in venous bleed

Question 18

What is this?

Answer 18

Epidural haematoma

Question 19

What is this?

Answer 19

subdural haematoma

Question 21

Different types herniation in the brian

Answer 21

Uncal herniation – oculomotor nerve compressed, eye gaze. Uncul sits next to anterior circulation so often see similar effects to AC stroke like motor deficits, sensory deficits, confusion etc. In extreme cases can get loss movements, motor function and LMN control on side affected as can affects tracts.

Tonsillar herniation – press of brain stem. Duret haeemorrhage – in midbrain and pons, fatal usually. Compress Postrema area- known to innervate dorsal nucleus of vagus which causes vomiting.

Question 22

What view is this?

Answer 22

Coronal

Question 23

What plane is this?

Answer 23

Sagittal

Question 24

What plane is this?

Answer 24

Axial/horizontal

Question 25

What is raised intracranial pressure

Answer 25

Growing pressure inside your skull. Many things can lead to this such as: increased CF production at choroid plexus, reduced drainage CSF across arachnoid granulations, increased venous sinus pressure (venous sinus thrombosis, obesity -effects adipokines, female), increase in inflammatory or thrombophilic factors and impaired lymphatic drainage.

Question 26

What is ischaemia and infarction

Answer 26

Ischaemia = insufficient supply blood to organ or tissue. This leads to tissue death (ie cellular necrosis) which is termed infarction. Infarction = Death of tissue resulting from failure of blood supply.

Question 27

Thrombosis and embolism def

Answer 27

* Thrombosis = when blood clots block veins or arteries * Embolism = blood clot that forms in a blood vessel in one area of body, breaks off and travels to another area of the body in the blood.

Question 28

Difference between stroke and TIA

Answer 28

Stroke = serious life threatening medical condition when blood supply to the brain is cut off. Can be hemorrhagic (weakened/diseased blood vessels rupture and blood leaks into tissue) or ischaemic where blood clots stop the flow of blood t an area of the brain TIA = temporary disruption in blood supply to part of the brain.

Question 29

Why are benign tumours in the brain often more clinically significant than benign tumours in other sites e.g the skin?

Answer 29

5 year survival of brain cancer is much lower than other cancers. For neurological components, don’t get pain from tumour as brain tissue not innervated by somatosensory nerve, you really only get symptoms due to build up of intracranial pressure which can be quite late or as result of tumoru impinging on neurological structure. Surgery and treatment is extremely challenging.

Question 30

What layer of meninges is visibl left to right

Answer 30

Question 32

This is a large haemorrhage that is a result of middle cerebral artery (M1 section). This would supply a lot of lateral surface of brain

Question 33

Answer 33

Bleeding and vascular abnormalities all around cortex so probably blunt head trauma. Not focal

Question 34

Answer 34

Haemorrhagic stroke, more focal, will be result of haemorrhage or focal haemorrhages in lenticular striate branch of M1.

Question 35

Answer 35

Formation of viscous cyst, as a result of action of microglia causing liquefactive necrosis.

Question 36

Give three examples of pathological processes that could lead to a raised intracranial pressure.

Answer 36

Meningitis (bacterial or viral), haematoma (epidural or subdual) , tumour

Question 37

What are the mechanisms underlying cerebral oedema?

Answer 37

* Cytotoxic- BBB remains in tact. Breakdown in metabolism neurones that leads to lack of function of Na/K+ pump so not normal concentration gradients therefore sodium flux into neurone, depletion extracellular sodium so swelling of neurone and neuronal death * Ionic oedema – intact BBB, but have osmotic gradient set up across BBB which leads to transfer water cross BBB down osmotic gradient hence brain swelling * Vasogenic oedema – BBB breaks down and so get seeping fluid into brain parenchyma and hence death neurones.

Question 38

What is a space occupying lesion? Give three examples.

Answer 38

* Cysts – aftereffects of liquefactive cellular necrosis * Haematomas or haemorrhages from stroke * Tumours

Question 40

Explain why patients with raised intra-cranial pressure develop vomiting, headache and papilloedema.

Answer 40

Raised ICP can compress brainstem affecting function of area postrema. Raised ICP can be meningeal too. Dira mater is innervated hence why get back headache. Arachnoid mater extends down optic nerve to lamina cribrosa and makes subarachnoid space extend to head optic nerve/disct. So ophthalmology you can see papilloedema (Blurring of disc from raised ICP in subarachnoid space surrounding optic nerve)

Question 41

GCS

Answer 41

Question 42

types haemorrhage

Answer 42

Question 43

Vlood supply in brain sections to identify on images

Answer 43

Question 44

Papillooedma

Answer 44