Increased ICP Flashcards
causes of increased ICP
idiopathic
infection
inflammation
space-occupying lesions
hydrocephalus
metabolic disturbance e
levated venous pressure
complications of increased ICP
decreased cerebral perfusion pressure
herniation
Cushing triad
coma
irreversible loss of brain function
apnea
cerebral edema
Mechanism of Vasogenic Edema
increased ECF due to disruption of the BBB and increased vascular permeability
Morphology findings of vasogenic edema
protein-rich infiltrated from a paucity of lymphatics
Mechanism of interstitial edema
CSF is blocked in periventricular white matter due to hydrocephalus
Mechanism of cytotoxic edema
increased ECF secondary to neuronal, glial or endothelial membrane injury
Mechanism of Subfacine (Cingulate) Herniation
gyrus of one hemisphere is compressed and herniates under the falx cerebri
complications of subfalcine herniation
obstruction of foramen of Monro leads to hydrocephalus
contralateral lower limb hemiparesis
hydrocephalus
Subfalcine (Cingulate) Herniation
Mechanism of Uncal Herniation
medial temporal lobe herniates at the free margin of the tentorium, compressing ipsilateral
CN3
PCA
cerebral peduncle
brain stem
blown pupil with ptosis and down/ out positioning
contralateral homonymous hemianopia with macular sparing
hemiparesis
Duret hemorrhages
Uncal herniation
respiratory arrest
unstable blood pressure
impaired circulation
tonsillar herniation
mechanism of tonsillar herniation
cerebellar tonsil herniates through the foramen magnum, compressing the medulla
what is Cushing’s triad
Bradycardia
HTN
Irregular breathing
Difference between communicating and noncommunicating hydrocephalus
Communicating: impaired absorption/ production of CSF
Noncommunicating: obstruction of CSF passage from ventricles to SA space
signs of Normal pressure hydrocephalus
wet
wacky
wobbly
What is hydrocephalus ex vacuo
hydrocephalus due to decreased brain mass
Delineate Cushing’s Triad
- increased ICP leads to decreased CCP
- Decreased CCP eads to compensatory activation of sympathetics to maintain perfusion
- increased sympathetics increases BP
- increased BP stimulates aortic arch baroreceptors to activate parasympathetics
CCP equation
Mean arterial pressure- ICP
What is pseudomotor cerebri
idiopathic mismatch between production and reabsorption of CSF, causing damage to structures of CNS and optic nerve fibers
clinical presentation of pseudomotor cerebri
recurrent HA (worse with lying down)
transient vision loss
flashing lights (photopsia)
double vision
retrobulbar pain
pulsatile tinnitus
Diagnostics of pseudomotor cerebri
high opening CSF pressure
Normal CSF analysis
6th nerve palsy
Bilateral papilledema
chronically elevated ICP in absence of ventricular enlargement or ass lesion
Pseudomotor cerebri
contraindications of IV mannitol to reduce elevated ICP
anuria
progressive heart failure
severe pulmonary edema
severe pre-existing dehydration
Normal ICP
~15cm H20
