Cerebral Perfusion and Intracranial Pressure Flashcards
what is vasogenic oedema?
when there is disruption of the blood brain barrier
what oedema is caused by membrane failure?
cytotoxic oedema influx of Ca creating cellular swelling
what are some secondary effects of raised ICP?
> herniation syndromes
> decreased cerebral perfusion
what is the munro kellie doctrine?
(brain + blood + CSF) volume = intracranial space. this must remain constant
in the adult brain how much of the cardiac output does the brain receive?
15%
what is the myogenic mechanism?
auto-regulation where vascular smooth muscle constricts in response to an increase in wall tension
what does a subfalcine herniation affect?
medial motor cortex
what may an uncal herniation affect?
> CN 3
ipsilateral corticospinal tracts
what sort of herniation would cause brain stem damage?
foramen magnum herniation
what management may a patient with raised ICP receive in ITU?
> 30 degree head position > no impediment of venous drainage > CO2 maintained below normal range > intermittent boluses of mannitol when ICP raised > fully sedated and paralysed
what surgical interventions can be carried out to reduced inter-cranial pressure?
> craniotomy and evacuation of clot
external ventricular drainage
decompressive craniectomy
list some common indications to perform a CT scan
> Head trauma > acute stroke > headache (sub arachnoid haemorrhage) > cancer > post surgical
what would indicate a MRI?
> demyelination > CNS tumours > suspected disc prolapse > TIA > epilepsy > paediatric neurology > headache > cancers
state some contraindications to perform a MRI
> cardiac pacemakers/cochlear implants
programmable shunts/insulin pumps (relative)
moveable metallic implants
for what can angiography be used?
diagnosis and treatment of vascular abnormalities: > aneurysm > arteriovenous malformation > carotidocavernous fistula > unstoppable epistaxis
