Raised ICP, S.O.L and Trauma NeuroPathology

Question 1

What can cause a raised intracranial pressure (ICP)?

Answer 1

• IncreasedCSF production(hydrocephalus)
• Focallesioninbrain(SpaceOccupyingLesions)
• Diffuselesioninbrain(e.g.oedema)
• Increasedvenousvolume
• Physiological(hypoxia,hypercapnia,pain)

Question 2

What is responsible for the re-absorption of CSF?

Answer 2

Arachnoid granulations

Question 3

What should normal CSF contain and NOT contain?

Answer 3

Small amount of protein and lymphocytes
Glucose
No neutrophils
No RBCs

Question 4

What is the difference between Non-Communicating and Communicating hydrocephalus?

Answer 4

Non-Communicating: ObstructiontoflowofCSFoccurs withinventricularsystem

Communicating: ObstructiontoflowofCSF OUTSIDEofventricularsystem e.g.insubarachnoidspaceorat thearachnoidgranulations

Question 5

What happens if hydrocephalus occurs before the cranial sutures close?

Answer 5

cranialenlargementoccurs

Question 6

What is hydrocephalus ex vacuo?

Answer 6

• Dilatationoftheventricularsystem=> increase in CSF volume
• due tolossofbrain parenchyma(e.g.in Alzheimer’sDisease)

Question 7

What are the effects of raised ICP?

Answer 7

• Intracranialshiftsandherniations
• Pressureon cranialnerves
• Impairedbloodflow
  (CerebralPerfusionPressure= MAP–ICP)
• Reducedlevelofconsciousness

Question 8

Describe how the brain can shift and herniate in raised ICP, and what each shift can compress?

Answer 8

• Subfalcine - moves under falx cerebri, can squish anterior cerebral artery
• Tentorial - squishes CN III => blown out pupil
• Cerebellar - compresses brainstem
• Transcalvarial - moves through skull fracture

Question 9

What are the main clinical signs of raised ICP?

Answer 9

Papilloedema
Headache
Neck stiffness (due to dura compression)
N+V

Question 10

What SOLs can be responsible for a raised ICP?

Answer 10

Tumour
Abscess
Haematoma
Local swelling (e.g. oedema around infarct)

Question 11

Where do tumours arise in children vs adults, in relation to the tentorium cerebelli?

Answer 11

children = tumours below TC
adults = tumours above TC

Question 12

What types of cancer most commonly metastasise to the brain?

Answer 12

Breast
Bronchus
kidney
thyroid
colon

Question 13

Where in the brain are metastases most likely to present?

Answer 13

Oftenseenattheboundariesbetweengreyandwhite matter

Question 14

What type of malignant primary tumour is most common in adults vs children?

Answer 14

Adults = Astrocytoma

Children = Medulloblastoma

Question 15

What type of benign brain tumour is most common in adults?

Answer 15

Meningioma

Question 16

WHat type of Grade 1 astrocytomas do children normally develop?

Answer 16

Pilocytic

Question 17

What signs can be seen on histology which point towards a higher grade tumour?

Answer 17

Abnormal cells
Mitotic figures (proliferation)
Anaplasia
Neoangiogenesis

Question 18

How do meulloblastomas appear on histology, and why is this clinically significant?

Answer 18

Cells are primitive undifferentiated embryonic cells

=> respond extremely well to radiotherapy

Question 19

Where do medulloblastomas usually occur in the brain?

Answer 19

Occursinthemidlineofthecerebellum

Question 20

Describe the difference in cause of a single abscess vs multiple abscesses?

Answer 20

Single - usually adj. to source
e.g. mastoiditis infection, next to fracture site

Multiple - haematogenous spread
e.g. pneumonia, endocarditis

Question 21

How are abscesses diagnosed?

Answer 21

• CTorMRI

- Aspirationforcultureandtreatment (weeks of antibiotics)

Question 22

How does bacterial meningitis cause raised ICP?

Answer 22

inflammation of meninges irritates the arachnoid granulations => prevents them from reabsorbing CSF

Question 23

Describe what is meant by a penetrating (missile) injury?

Answer 23

• Focaldamage
• Lacerationsinregionofdamage
• Haemorrhage
• Cavitation depending on high/low velocity

Question 24

What is a Blunt or non-missile injury?

Answer 24

• Suddenacceleration/decelerationofhead •Thesmallerthecontacttimeis,thelargertheforce
• Brainmoveswithinthecranialcavityandmakescontactwith the craniumandbonyprotrusions

Question 25

What can cause blunt/non-missile injury?

Answer 25

• Roadtrafficcollisions(RTCs)
• Falls
• Assaults
• Alcohol

Question 26

Primary injury is usually irreversible. TRUE/FALSE?

Answer 26

TRUE
damage to neurones means they cant regenerate
- preventative measures (seatbelts, crashmats) can be used to increase contact time)

Question 27

What are coup and contra-coup injuries?

Answer 27

Coup - Occurs at point of impact

Contra-coup - occurs opposite point of impact, due to rebound, often worse than initial injury

Question 28

A linear fracture across the squamous part of the temporal bone would cause which artery to rupture?

Answer 28

Middle meningeal artery

=> would cause an extradural haematoma

Question 29

What is diffuse axonal injury?

Answer 29

• Occursatmomentofinjury
• Affectscentralareas
• Sheering of axons => electrical signals cant transfer
• Reducedconsciousnessand coma
• Axons become “axonal bulbs”

Question 30

What injury often causes an extradural haematoma and what are the consequences of this?

Answer 30

• fractureintempero‐parietal(middlemeningeal artery)
• Immediatebraindamage oftenminimal
• Untreated =midlineshift– compressionandherniation

Question 31

What causes a subdural haematoma and what are the complications of this?

Answer 31

• disruptionofbridgingveins
• Swellingofcerebrumon sideofhaematoma
• Non‐treated,nonfatal haematomasbecome liquefiedandforma yellowishneomembrane (chronic)