Raised ICP, S.O.L and Trauma NeuroPathology Flashcards
What can cause a raised intracranial pressure (ICP)?
- IncreasedCSF production(hydrocephalus)
- Focallesioninbrain(SpaceOccupyingLesions)
- Diffuselesioninbrain(e.g.oedema)
- Increasedvenousvolume
- Physiological(hypoxia,hypercapnia,pain)
What is responsible for the re-absorption of CSF?
Arachnoid granulations
What should normal CSF contain and NOT contain?
Small amount of protein and lymphocytes
Glucose
No neutrophils
No RBCs
What is the difference between Non-Communicating and Communicating hydrocephalus?
Non-Communicating: ObstructiontoflowofCSFoccurs withinventricularsystem
Communicating: ObstructiontoflowofCSF OUTSIDEofventricularsystem e.g.insubarachnoidspaceorat thearachnoidgranulations
What happens if hydrocephalus occurs before the cranial sutures close?
cranialenlargementoccurs
What is hydrocephalus ex vacuo?
- Dilatationoftheventricularsystem=> increase in CSF volume
- due tolossofbrain parenchyma(e.g.in Alzheimer’sDisease)
What are the effects of raised ICP?
- Intracranialshiftsandherniations
- Pressureon cranialnerves
- Impairedbloodflow
(CerebralPerfusionPressure= MAP–ICP) - Reducedlevelofconsciousness
Describe how the brain can shift and herniate in raised ICP, and what each shift can compress?
- 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
What are the main clinical signs of raised ICP?
Papilloedema
Headache
Neck stiffness (due to dura compression)
N+V
What SOLs can be responsible for a raised ICP?
Tumour
Abscess
Haematoma
Local swelling (e.g. oedema around infarct)
Where do tumours arise in children vs adults, in relation to the tentorium cerebelli?
children = tumours below TC adults = tumours above TC
What types of cancer most commonly metastasise to the brain?
Breast Bronchus kidney thyroid colon
Where in the brain are metastases most likely to present?
Oftenseenattheboundariesbetweengreyandwhite matter
What type of malignant primary tumour is most common in adults vs children?
Adults = Astrocytoma
Children = Medulloblastoma
What type of benign brain tumour is most common in adults?
Meningioma
WHat type of Grade 1 astrocytomas do children normally develop?
Pilocytic
What signs can be seen on histology which point towards a higher grade tumour?
Abnormal cells
Mitotic figures (proliferation)
Anaplasia
Neoangiogenesis
How do meulloblastomas appear on histology, and why is this clinically significant?
Cells are primitive undifferentiated embryonic cells
=> respond extremely well to radiotherapy
Where do medulloblastomas usually occur in the brain?
Occursinthemidlineofthecerebellum
Describe the difference in cause of a single abscess vs multiple abscesses?
Single - usually adj. to source
e.g. mastoiditis infection, next to fracture site
Multiple - haematogenous spread
e.g. pneumonia, endocarditis
How are abscesses diagnosed?
- CTorMRI
- Aspirationforcultureandtreatment (weeks of antibiotics)
How does bacterial meningitis cause raised ICP?
inflammation of meninges irritates the arachnoid granulations => prevents them from reabsorbing CSF
Describe what is meant by a penetrating (missile) injury?
- Focaldamage
- Lacerationsinregionofdamage
- Haemorrhage
- Cavitation depending on high/low velocity
What is a Blunt or non-missile injury?
- Suddenacceleration/decelerationofhead •Thesmallerthecontacttimeis,thelargertheforce
- Brainmoveswithinthecranialcavityandmakescontactwith the craniumandbonyprotrusions
What can cause blunt/non-missile injury?
- Roadtrafficcollisions(RTCs)
- Falls
- Assaults
- Alcohol
Primary injury is usually irreversible. TRUE/FALSE?
TRUE
damage to neurones means they cant regenerate
- preventative measures (seatbelts, crashmats) can be used to increase contact time)
What are coup and contra-coup injuries?
Coup - Occurs at point of impact
Contra-coup - occurs opposite point of impact, due to rebound, often worse than initial injury
A linear fracture across the squamous part of the temporal bone would cause which artery to rupture?
Middle meningeal artery
=> would cause an extradural haematoma
What is diffuse axonal injury?
- Occursatmomentofinjury
- Affectscentralareas
- Sheering of axons => electrical signals cant transfer
- Reducedconsciousnessand coma
- Axons become “axonal bulbs”
What injury often causes an extradural haematoma and what are the consequences of this?
- fractureintempero‐parietal(middlemeningeal artery)
- Immediatebraindamage oftenminimal
- Untreated =midlineshift– compressionandherniation
What causes a subdural haematoma and what are the complications of this?
- disruptionofbridgingveins
- Swellingofcerebrumon sideofhaematoma
- Non‐treated,nonfatal haematomasbecome liquefiedandforma yellowishneomembrane (chronic)
