neural bleeds Flashcards
(35 cards)
remember the different lobes, important sulcus’s,
what are the tentoriums and the structures contained in each one
supratentoriaum = cerebrum (above tentorium cerebelli)
intratentorium (below tentorium cerebella) = cerebellum
what is ‘coning’ of the cerebellum
he cerebellar tonsils move downward through the foramen magnum possibly causing compression of the lower brainstem and upper cervical spinal cord as they pass through the foramen magnum.
what are the 2 main dura folds in the brain and their purpose
falx cerevri = touch membranous structure, separates cerebral hemispheres
tenttorium cerebelli = seperates cerebrum from cerebellum and brains tem
function of cerebellum?
smooth, coordinated body movement
what are the 3 meninges layers of the brain?
dura mater (surround and protect brain and spinal cord) (outermost)
arachnoid (It’s a thin layer that lays between your dura mater and pia mater) (no vasculature contained)
(middle)
pia mater (inner layer, closest to your brain tissue.)(allows blood vessels to passs to nourish brain) (innermost)
what are the 3 menigial SPACES of the brain and what is contained in each one
extradural = between skull and dura (meningeal ARTERIES)
subdural = between dura and arachnoid (a thin layer of serous fluid. It allows the dura to move over the arachnoid.)
subarachnoid = between arachnoid and pia (CSF and major blood vessels)
what is the morno-kellie hypothesis
the sum of volumes of brain, CSF, and intracranial blood is constant
and increase in either CSF OR intracranial blood = decrease in the other
- used to identify leaking csf (more blood than csf) or intracranial hypertension (more csf than blood) in brain
how do brain herniations generally occur and how is it resolved
increased pressure in skull forcing brain tissue to shift from on compartment to another e.g due to stoke, tumours, hydrocephalus, haemorrhage
- decompressive craniotomy ( removing part of skull and putting it back later, gives space for brain to swell instead of it swelling downwards and compressing on spinal cord)
( or regular craniotomy to allow access to fix Brain issue e.g hepatoma/blood clot)
what is the uncus of the brain
medial aspect of temporal lobe
what aspect of the ventricles generates CSF, how much a day is made and whats the purpose of it
Choroid plexus
400-700mls daily
- protection (cushion for brain), buoyancy (reduce effective weight of brain against spinal cord), removes metabolic waste, maintains homeostasis, nutrient transport
what might cause acute hydrocephalus? what are typical signs of this
- tumour blocking CSF flow = swelling
- no bright signal seen from CSF in axial slice
- no sulcus/gyri definition due to swelling
KNOW WHAT IT LOOKS LIKE
Why is acute haemorrhage hyperdence on CT, what is the hounsfield unit of blood
56 HU
due to high conc of haemoglobin thus protein content of acute haemorrhage = increased density compared to brain tissue
chronic subdural haemorrhage may look like CSF accumulation as bloods been there for long so it breaks down fluid components
ACUTE/FRESH BLOOD BRIGHT (HYPERDENSE)
CHRONIC/OLD BLOOD DARK (HYPODENSE)
What 2 terms are used to describe location of lesion or mass in relation to brain tissue location itself, whats the difference
INTRA axial
- within brain parenchyma (lobar, pontine, basal ganglia, cerebellar)
EXRA axail
- outside brain parenchyma but within skull (extra/sub dural, subarachnoid, intraventricula)
what blood is in extra dural haemorrhage, describe its shape and boundaries, and typical cause and region found
- arterial blood (as its between skull and dura mater where meningeal arteries lie)
- lentiform (lemon) shape
- doesnt cross suture lines (so can’t grow as large)
- commonly located near temporal bones, associated with fracture site
- overall trauma/fracture causation
what is pneumocephalus, what is a common sign of this on imaging?
presence of air in brain (small DARK bubble of gas, usually around site of injury/fracture)
KNOW WHAT IT LOOKS LIKE
IF THE HAEMORRAHGE LOOKS BLACK AND WHITE THEN ITS A MIXTURE OF PARTIALLY AND FULLY CLOTTED BLOOD (KNOW WHAT IT LOOKS LIKE)
what blood is in sub dural haemorrhage, describe its shape and boundaries, and typical cause and region found
- venous blood
- can cross suture lines so shape can expand and follow along edge of brain (not limited to lentiform shape like extradural)
- abuse in kids, long term alcohol abuse or elderly falls causation, on anticoagulants
- overall typically tear of cortical bridging vein causation
(know what it looks like)
know that some brains can have simultaneous chronic and acute haemorrhage so just know what they look like and identify on images
bleeds (typically arterial) strips dura from skull
- dura becomes more adherent to skull as u age
- at suture point, skull is tightly adherent to dura usually preventing crossing
Biggest cause of subarachnoid haemorrhage, describe its shape, effects of this
- typically due to rupture aneurysm (causing bleed all over) and bleeding into the subarachnoid region
- life threatening
- likely to cause seizures, vasospasm (narrowing of blood vessels in brain), hydrocephalus (accululation of CSF in brain)
(KNOW WHAT IT LOOKS LIKE)
NOTE: DEATH WITH SUBARACHNOID HAEMORRAHAGE IS MOST LIKELY DUE TO HYDROCEPHALUS CAUSATION NOT THE ACTUAL HAEMORRHAGE ITSELF
WHAT DO CLOTS LOOK LIKE ON BRIAN CT?
BRIGHT SPOTS WITHIN ARTERY !!
