Neuropathology 2: Raised ICP (SOL's) and Trauma

Question 1

Purpose of CSF?

Answer 1

Supports the brain (neutral buoyancy).

Question 2

Normal volume of CSF?

Answer 2

120-150ml. 500ml produced every 24 hours.

Question 3

Where is CSF produced?

Answer 3

Produced by the choroid plexus in the lateral and 4th ventricles.

Question 4

Where is the CSF absorbed?

Answer 4

Arachnoid granulations - these are herniations of the arachnoid mater that protrude into the dura mater.

Question 5

Normal appearance of CSF is a clear fluid. True/false?

Answer 5

True

Question 6

What does increased lymphocytes in the CSF indicate?

Answer 6

Infection (viral or fungal), autoimmune causes.

Question 7

What does increased neutrophils in the CSF indicate?

Answer 7

Infection (bacterial meningitis)

Question 8

Definition of hydrocephalus?

Answer 8

Accumulation of excess CSF within the ventricular system of the brain.

Question 9

How can hydrocephalus occur?

Answer 9

Obstruction to flow of CSF (e.g. inflammation, pus and tumours).

Decreased resorption of CSF (post SAH or meningitis).

Overproduction of CSF (very rare tumours of choroid plexus).

Question 10

2 types of hydrocephalus?

Answer 10

Non - communicating

Communicating

Question 11

What is non-communicating hydrocephalus?

Answer 11

When obstruction to flow of CSF occurs within the ventricular system.

Question 12

What is communicating hydrocephalus?

Answer 12

Obstruction to CSF flow occurs outside of the ventricular system e.g. subarachnoid space or at arachnoid granulations.

Question 13

If hydrocephalus develops before the closure of cranial sutures, then cranial enlargement occurs. True/false?

Answer 13

True

Question 14

If hydrocephalus develops after closure of cranial sutures, then there is constriction of ventricles and decrease in intracranial pressure. True/false?

Answer 14

False

There is EXPANSION of ventricles and intracranial pressure will INCREASE.

Question 15

What is hydrocephalus ex vacuo?

Answer 15

Occurs when a stroke or injury damages the brain and brain matter actually shrinks.

The brain may shrink in older patients or those with Alzheimer’s disease, and CSF volume increases to fill the extra space.

Ventricles are enlarged but pressure is usually normal.

Question 16

Causes of raised intracranial pressure?

Answer 16

Increased CSF (hydrocephalus)

Focal lesion in brain (space occupying lesions)

Diffuse lesion in brain (e.g. oedema)

Increased venous volume

Physiological (hypoxia, hypercapnia, pain)

Question 17

Effects of raised intracranial pressure?

Answer 17

Midline shift

Distortion and pressure on cranial nerves and vital neurological centres

Reduced conscious level

Impaired blood flow (CPP = MAP-ICP)

Question 18

Clinical signs of raised ICP?

Answer 18

Nausea + vomiting
Neck stiffness
Reduced conscious level
Headache
Papilloedema - swelling of the optic disc due to elevated intracranial pressure (ICP)

Question 19

Examples of SOL’s (space occupying lesions)?

Answer 19

Tumours - primary brain tumours/metastases

Abscesses - single/multiple

Haematomas

Localised brain swelling - e.g. swelling and oedema around cerebral infarct.

Question 20

How many astrocytoma grades are there by WHO?

Answer 20

Grades 1- 4

Question 21

WHO astrocytoma grade 1?

Answer 21

Grade 1 (pilocytic)

• Childhood
• Benign behaving
• Cystic areas
• Long hair-like processes

Question 22

WHO astrocytoma grade 2?

Answer 22

Grade 2 (well differentiated)

• Nuclear atypia (abnormal appearance of cell nuclei on histology)

Average 5yr survival

Question 23

WHO astrocytoma grade 3?

Answer 23

Grade 3 (anaplastic)

• Greater nuclear atypia
• Mitotic activity

Question 24

WHO astrocytoma grade 4?

Answer 24

Grade 4 (glioblastoma)

• Extreme atypia
• Mitotic activity
• Necrotic and/or neovascularisation

Less than 10-12 month survival

Question 25

What is the most common tumour in children?

Answer 25

Medulloblastoma (closely followed by pilocytic astrocytomas).

Question 26

Where does medulloblastoma occur?

Answer 26

Midline of cerebellum, it can disrupt CSF flow leading to hydrocephalus.

Question 27

How are brain abscesses diagnosed?

Answer 27

CT or MRI scan

Question 28

Main symptoms of brain abscess?

Answer 28

Raised ICP
Fever

Will display symptoms depending on underlying cause

Question 29

The organisms implicated depend on the underlying cause. What are some main examples of the causative organisms?

Answer 29

Staph aureus
Aerobic and anaerobic streptococci

Immunocompromised:
- Fungi
- Protozoa e.g. toxoplasma in AIDS

Question 30

Definition of bacterial meningitis?

Answer 30

Inflammation of leptomeninges and CSF within subarachnoid space.

Frequently causing severe oedema and raised ICP.

Question 31

Bacterial meningitis on CSF?

Answer 31

Abundant polymorphs and decreased glucose on CSF.

Question 32

2 types of traumatic head injury?

Answer 32

Missile (penetrating)
Non-missile (blunt)

Question 33

Blunt head injury features and causes?

Answer 33

Sudden acceleration/deceleration of head.
Smaller contact time = larger force
The brain moves within the cranial cavity and makes contact with the inner table of the cranium and bony protrusions.

Causes:
Road traffic accident
Falls
Assault
Alcohol (around 1/2 of cases)

Question 34

Types of skull fracture?

Answer 34

Linear - straight sharp fracture line, that may cross sutures
Compound - associated with full thickness scalp lacerations
Depressed

Question 35

Base of skull fractures - linear. True/false?

Answer 35

False. Compound fractures.

Question 36

Coup injury?

Answer 36

Occurs to the brain on the side of impact

Question 37

Contra-coup injury?

Answer 37

Diametrically opposite the point of impact

Question 38

Diffuse axonal injury, definition and features?

Answer 38

The shearing (tearing) of the brain’s long connecting nerve fibers (axons) that happens when the brain is injured as it shifts and rotates inside the bony skull.

Reduced consciousness and coma
Can lead to vegetative state