Raised ICP, Space Occupying Lesions & Trauma Flashcards
what can cause a raised ICP?
increased CSF production (hydrocephalus) focal lesion in brain (SOL) diffuse lesion in brain (oedema) increased venous volume physiological (hypoxia, hypercapnia, pain)
what is responsible for re-absorption of CSF?
arachnoid granulations
what should normal CSF contain and not contain?
contain small amount of protein and lymphocytes and glucose
no neutrophils or RBCs
what is the difference between non-communicating and communicating hydrocephalus?
non communicating = obstruction to flow of CSF occurs within ventricular system
communicating = obstruction to flow of CSF outside of ventricular system eg in subarachnoid space or at arachnoid granulations
what happens if hydrocephalus occurs before cranial sutures close?
cranial enlargement
what is hydrocephalus ex vacuo?
dilation of ventricular system - increase in CSF volume
due to loss of brain parenchyma (eg in alzheimer’s disease)
what are the effects of raised ICP?
intracranial shifts and herniation
pressure on cranial nerves
impaired blood flow (CPP = MAP - ICP)
reduced level of consciousness
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 CNIII - blown out pupil
cerebellar = compresses brainstem
transcalvarial = moves through skull fracture
what are main clinical signs of raised ICP?
papilloedema
headache
neck stiffness (due to dura compression)
N&V
what SOLs can be responsible for raised ICP?
tumour
abscess
haematoma
local swelling (eg oedema around infarct)
where do tumours arise in children vs adults in relation to tentorium cerebelli?
children = tumours below TC adults = tumours above TC
what types of cancer most commonly metastasise to brain?
breast bronchus kidney thyroid colon
where in the brain are metastases most likely to present?
often seen at boundaries between 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