L17 Neuropathology

Question 1

Hydrocephalus ex vacuo

Answer 1

Enlargement of ventricles and subarachnoid space due to shrinking of brain

Occurs in dementia

Question 2

What happens when hydrocephalus occurs in infants?

Answer 2

Hydrocephalus occurring before fusion of the cranial sutures causes enlargement of the head circumference

Question 3

What is characteristic of tonsillar herniation at autopsy?

Answer 3

Duret haemorrhage - these are small linear bleeds in the midbrain and upper pons

Question 4

What are the 3 types of herniation?

Answer 4

Subfalcine- displacement of cingulate gyrus beneath free edge of falx cerebri

Central/transtentorial- cerebral hemisphere tissue pushed through tentorium cerebelli

Tonsillar/cerebellar- cerebellar tissue pushed through foramen magnum
-can compress medulla obl

Question 5

Give examples of space occupying lesions

Answer 5

Haemorrhages

• extradural
• subdural
• subarachnoid
• intracerebral

Neoplasm
Abscess

Question 6

Vascular brain injury causes

• extradural
• subdural
• subarachnoid
• intraparenchymal

Answer 6

Extradural bleed

• arterial laceration of MMA
• severe trauma

Subdural

• trauma minor in atrophy
• caused by ruptured vein (bridging vein)/venous laceration
• seen in old age

Subarachnoid
Rupture of saccular (berry) aneurysm in circle of Willis

Intraparenchymal

• bleeding into the brain
• hypertension

Question 7

Berry/saccular aneurysm

Answer 7

• mainly affects anterior communicating, middle cerebral, ICA, tip of basilar
• can lead to subarachnoid haemorrhage if ruptures

Question 8

Causes of cerebral oedema

Answer 8

Vasogenic
-increased vascular permeability

Cytotoxic
-neuronal, glial/endothelial cell damage

Question 9

What causes raised intracranial pressure?

What can this lead to?

Answer 9

CSF pressure above 200mm H2O

Causes

• Hydrocephalus
• Intracranial space occupying lesion (neoplasm, haemorrhage, abscess)
• Cerebral oedema

Can result in herniation

Question 10

Extradural haemorrhage

Answer 10

Severe trauma with arterial laceration- MMA

Question 11

Subdural haemorrhage

Answer 11

Trauma may be minor in atrophy (bridging veins)

Question 12

Subarachnoid haemorrhage

Answer 12

Rupture of saccular (berry) aneurysm (circle of Willis)

-anterior communicating

Question 13

Cerebral oedema causes

Answer 13

Vasogenic Increased vascular permeability

Cytotoxic Neuronal, glial or endothelial cell damage

Question 14

A burst saccular aneurysm can lead to what?

Answer 14

subarachnoid haemorrhage

Question 15

Subfalcine can compress which artery?

Answer 15

anterior cerebral artery

Question 16

Transtentorial- symptom

Answer 16

oculomotor nerve compression with blown pupils

Question 17

Tonsillar herniation- compression of what structures?

Answer 17

compression of vital respiratory and cardiac centres in the medulla oblongata with secondary brainstem trauma=Duret haemorrhages

Question 18

Complications associated with subarachnoid haemorrhages

Answer 18

Acute complications: vasospasm leading to focal/global ischaemia, very serious complication, may be fatal. Late complications: hydrocephalus owing to scarring and CSF flow obstruction.