hydrocephalus & hematoma Flashcards
meninges
dura mater
arachnoid mater
pia mater
arachnoid villi
reabsorb CSF
resorption rate=
production rate
composition of CSF
arise from plasma but contains more Na, Cl & H
less Ca & K
functions of CSF
mechanical protection
chemical protection
circulation
BBB
very selective
allows essentials in
remove wastes
areas that don’t have CSF
near respiratory system where CO2 measured
wall of 3rd ventricle where glucose is measured
% of O2 brain uses
20%
hypoxic injury
deprived of O2 due to decreased blood flow
causes- reduced atmospheric pressure, CO poisoning, failure oxygenating blood
ischemic injury
greatly reduced or interrupted blood flow
lack of O2, glucose, & removal of wastes
increase in NA+ leads to
interstitial edema
influx in Ca leads to
cell death
watershed infarcts
toward the surface with major vessels
laminar necrosis
deeper in the brain with smaller vessels
how to treat global ischemia
hypothermia
restore blood vol
control blood glucose
many neurological disorders are caused by
overstimulation of excitatory neurotransmitters
NMDA
required for higher brain functions
non communicating
occurs due to obstruction
CSF not reabsorbed by villi
how can CSF be obstructed?
congenital malformation (narrowing) tumor inflammation hemorrhage injury viral infection
congenital hydrocephalus
in newborn, fontanels allows increased pressure to expand skull
communicating hydrocephalus
no obstruction due to impaired reabsorption by villi causes= fewer villi head injury adenoma of choroid plexus
ICP
increased intracranial pressure
happens in acute but not seen in slowly developing
parts of a shunt
valve, tube, reservoir
purpose of shunt
redirect CSF to other part of body that can absorb
complications= infections, bleed, over or under drain
hematoma
epidural
subdural (acute, subacute, chronic)
intracerebral
epidural hematoma
caused by blow to the head, arterial in origin
subdural hematoma
between dura and arachnoid
venous in origin
develops slow
acute subdural
24 hrs
quick, increased ICP
subacute
2-10 days
significant neurologic defects
chronic
weeks or months
slow bleed
acute intra-cerebral
injury
common in older and alcoholics (weak vessels)
bleed in brain tissue
treatment for hematoma
surgical evacuation of hematoma
secondary injury for hematoma
intracerebral hemorrhage
edema
CPP
cerebral perfusion pressure
70-100 mmHg
below 70= ischemia
formula to calculate CPP
CPP=MAP-ICP
