14: Ventricular System, SC, Damage To Brain Flashcards
What causes epidural vs subdural hematoma?
Epidural: middle meningeal rupture
Subdural: cerebral bridging veins rupture
What happens in the brain during an epidural hematoma?
Midline shift of cerebral hemispheres -> falx and/or uncal herniations
S/S epidural hematoma vs subdural
Epidural: initial unconsciousness with rapid recovery, papilledema, lethargy, SZR, HA
Subdural: same as epidural, but can be delayed for days/weeks
What causes subarachnoid hemorrhage
Rupture of any major blood vessel in brain
What would lead you to suspect a subarachnoid hemorrhage
RBCs in CSF on LP
Two things that can occur Post-SAH
- Arachnoid villi become clogged -> transient hydrocephalus
2. Hemolyzed RBCs in CSF -> secondary (chemical) meningitis
Two types of uncal herniations
Falx (subfalcine), transtentorial
Falx herniation
Cerebrum herniates under falx cerebri
Transtentorial herniation
Cerebrum herniates through tentorial notch
S/S uncal herniation
Progressive decrease in consciousness
What A can be occluded in an uncal herniation, and what can that cause?
PCA occlusion -> ischemic necrosis of primary visual cortex -> contralateral homonymous hemianopsia with macular sparing
Tonsillar herniation
Mass in posterior cranial fossa -> cerebellar tonsil herniates through foramen magnum
What is compressed in tonsillar herniation
Lower medulla, upper cervical SC
What condition can cause tonsillar herniation
Arnold-Chiari malformation
Ischemic penumbra
Tissue surrounding the core ischemic territory - is too ischemic to function, but is critically viable and can be rescued with stroke therapy
Central cord syndrome: caused by
ASpA disruption
Central cord syndrome - what happens to the SC?
Central necrosis and cavitation, development of a syrinx
S/S central cord syndrome, anterior, and posterior
Central: abrupt onset neurological S/S with amelioration
Anterior: motor paralysis below lesion, loss of pain and temp
Posterior: loss of proprioception and vibration below lesion
What can cause anterior cord syndrome
Flexion injuries, injury to ASpA
Lining of ventricular system
Ependymal cells
What separates the two lateral ventricles
Septum pellucidum
lateral ventricle: anterior horn, body, posterior horn, inferior horn locations
Anterior horn: frontal lobe
Body: parietal lobe
Posterior: occipital lobe
Inferior: temporal lobe
Third ventricle location
Between thalami
Fourth ventricle shape
Four-sided pyramid
Fourth ventricle location
Between cerebellum + pons
Base and apex of fourth ventricle
Base: formed by tegmentum of
Metencephalon
Apex: towards cerebellum
Where does the obex lead from the fourth ventricle?
A blind-ended central canal
What layer of meninges is related to choroid plexus
Pia mater
Hydrocephalus
Increase in cerebral size/mass due to excess CSF in ventricular system, subarachnoid space, or both
Clinical signs of hydrocephalus
Strabismus (abducens palsy), sundown gaze, papilledema
External hydrocephalus
Excess CSF in subarachnoid space + enlargement of space due to compression of CNS
Two types of external hydrocephalus
Supratentorial external and infratentorial external
Supratentorial external hydrocephalus is associated with what?
Senile atrophy of cortex (ex: Alzheimer’s)
Internal hydrocephalus is also called what?
Non-communicating hydrocephalus
What causes internal hydrocephalus
Obstruction somewhere in ventricular system
What does internal hydrocephalus cause?
Dilation of ventricles proximal to obstruction
Communicating hydrocephalus
Infratentorial external hydrocephalus + internal hydrocephalus
Obstruction in communicating hydrocephalus
Obstruction in space between tentorial notch and midbrain, the only communication of CSF from posterior cranial fossa to supratentorial region
What happens in communicating hydrocephalus?
Hypertrophy of ventricles + accumulation of CSF in infratentorial area
