B7-056 Meningoencephalitis Flashcards
tough connective tissue that divides the hemispheres into left and right
falx cerebri
tough connective tissue separates the cerebrum from the cerebellum/brainstem
tentorium
(used to divide the supratentorial compartment from the infratentorial compartment)
the enlargements of intra-axial CSF spaces are called
cisterns
CSF is produced in the
choroid plexus
rate of production of CSF by the choroid
500ml per day
(normal volume is 125, so completely replaces volume several times a day)
CSF circulation enters the extra-axial space via medial and lateral apertures at the […]
medulla
CSF is reabsorbed over the […] at the superior sagittal sinus
arachnoid granulations
for normal CSF flow, the pressure in the […] has to be greater than pressure in the […]
ventricles
subarachnoid space
[…] between capillary endothelial cells forms the BBB
tight junctions
tight junctions of the […] cells prevent solutes from moving from CSF into the brain
ependymal cells
locations in the brain where the BBB is interrupted [3]
pineal gland
neurohypophysis of pituitary
area postrema
types of herniation [4]
sub-falcine
central
uncal
tonsillar
midsize bilateral, non reactive pupils
[…] herniation
central herniation
unilateral dilated, non-reactive pupil
[…] herniation
lateral (uncal)
most vulnerable CN to meningitis
VIII
treatment for suspected acute bacterial meningitis
ampicillin and ceftriaxone
CSF WBCs are less than 100
non-acute meningitis (viral, aseptic, fungal, cancer, autoimmune, etc)
CSF WBCs are more than 200
consider acute bacterial meningitis
neutrophils in CSF fluid
acute bacterial meningitis
obstruction to CSF flow is intra-axial
non-communicating hydrocephalus
most common location of a lesion causing non-communicating hydrocephalus
cerebral aqueduct
enlarged ventricles, but 4th ventricle is not enlarged
non-communicating hydrocephalus
obstruction to CSF flow is extra-axial
communicating hydrocephalus
all ventricles enlarged, even 4th
communicating hydrocephalus
typically due to interruption of CSF flow percolating trough subarachnoid space
communicating hydrocephalus
(ex. scarring from meningitis)
symptoms of hydrocephalus [3]
gait problems
incontinence
cognitive issues
in acute or subacute hydrocephalus the opening pressure will likely be
high
in chronic hydrocephalus the opening pressure will likely be
normal
very chronic communicating hydrocephalus is called
normal pressure hydrocephalus
hydrocephalus secondary to atrophy of the brain
no derangement in CSF flow
hydrocephalus ex vacuo
increased ICP due to poor absorption of CSF
no enlargement of ventricles
idiopathic intracranial hypertension
cause of idiopathic intracranial hypertension
poor absorption of CSF by arachnoid villi
idiopathic intracranial hypertension is associated with [4]
obesity
tetracycline
vitamin A
venous sinus thrombosis
headache
episodic blurred vision, diplopia
papilledema
normal head imaging
idiopathic intracranial hypertension
treatment of idiopathic intracranial hypertension [3]
diamox (decreases CSF production)
optic nerve fenestration
CSF shunt
lumbar puncture is contraindicated in patients with
focal mass lesions causing ICP
(not contraindicated in idiopathic intracranial hypertension because pressure is increased diffusely)
causes of intracranial hypotension [4]
post traumatic
encephalocele
tarlov cyst
idiopathic
orthostatic headaches
low opening pressure
intracranial hypotension
treatment for intracranial hypotension [2]
repair leak
blood patch
CN most likely to be affected by idiopathic intracranial hypertension?
2
dysfunction of short term memory requires […] dysfunction to the memory circuits
bilateral
inattention requires […] dysfunction of the dorsolateral prefrontal cortex
bilateral
imaging for venous sinus thrombosis
MRV
treatment of venous sinus thrombosis [3]
anticoagulation
catheter thrombectomy
lower ICP
basis of the BBB
tight junctions between endothelial cells
what type of herniation can compress the ACA?
subfalcine
what type of herniation causes caudal displacement of the brainstem?
central transtentorial
what type of herniation can cause rupture of the basilar artery branches (duret hemorrhages)?
central transtentorial
what type of herniation causes ipsilateral blown pupil with contralateral hemiparesis?
uncal herniation
what type of herniation causes coma/death when it compresses the brainstem?
cerebellar tonsillar herniation
which pupillary changes characterize central descending transtentorial herniation?
mid-range unreactive pupils
which pupillary changes characterize uncal herniation?
unilateral fixed dilated pupil
is the parasympathetic or sympathetic system affected by central descending transtentorial herniation?
both, that’s why pupil is mid-range
treatment for viral meningitis
IV acyclovir
most common form of sporadic viral encephalitis
herpes meningoencephalitis
describe the flow of CSF from production to absorption
lateral ventricles
3rd ventricles
cerebral aqueduct
4th ventricles
lateral and medial apertures
subarachnoid space
arachnoid granulations
venous sinuses
what structures surround the epidural space?
dura and skull
what structures surround the subdural space?
dura
arachnoid
what structures surround the subarachnoid space?
arachnoid
pia
the anterior temporal lobes are nested of the sphenoid wing of the […] cranial fossa
middle
the orbital frontal cortex is in the […] cranial fossa
anterior
the brainstem and cerebellum are in the […] cranial fossa
posterior
absence of hydrocephalus on MRI
severely elevated intercranial CSF pressure
idiopathic intracranial hypertension
enlarged lateral and third ventricles
normal sized fourth ventricle
non-communicating hydrocephalus
enlargement of all ventricles [2]
communicating hydrocephalus
normal pressure hydrocephalus
appearance of increased CSF on imaging but actually due to decreased brain tissue and atrophy
ex vacuo ventriclomegaly
ICP is […] in ex vacuo ventriclomegaly
normal
caused by structural blockage of CSF circulation within the ventricular system
non-communicating hydrocephalus
expansion of ventricles distorts fibers of the corona radiata
normal pressure hydrocephalus
decreased CSF absorption by arachnoid granulation causes increased ICP, papilledema, and herniation
communicating hydrocephalus
increased ICP with no obvious findings on imaging
idiopathic intracranial hypertension
risk factors of idiopathic intracranial hypertension
female
Tetracyclines
Obesity
A- Vitamin A excess
Danazol/Dural venous sinus thrombosis
female TOAD
associated with dural venous sinus stenosis
idiopathic intracranial hypertension
common symptoms of idiopathic intracranial hypertension
headache
papilledema
tinnitus
diplopia
visual field testing for idiopathic intracranial hypertension will reveal [2]
peripheral constriction
enlarged blind spot
treatment of idiopathic intracranial hypertension
weight loss
acetazolamide (carbonic anhydrase inhibitor)
invasive procedures for refractory cases
from first aid
