L1 Flashcards
disorders cause dangerous increase in the volume of intracranial contents
- Generalized cerebral edema
- Hydrocephalus
- Hemorrhages
- Ischemia
- Tumors
accumulation of
excess fluid within the brain parenchyma.
Cerebral edema
two types of cerebral edema
• Vasogenic edema
• Cytotoxic edema
integrity of the normal blood- brain barrier is disrupted
fluid to shift from the vascular compartment into the extracellular spaces of the brain.
Vasogenic Edema
Can be localised or generalized
is an increase in intracellular fluid secondary to neuronal and glial cell injury.
• It follow generalized hypoxic- ischemic insult or after exposure to some toxins.
Cytotoxic edema
CSF flows through the……………………. and
……………………into the subarachnoid space, where it is
absorbed by arachnoid granulations.
foramina of Luschka
Magendie
to an increase in the volume of
cerebrospinal fluid (CSF) within the ventricular system most often is a consequence of
• Impaired flow
• Decreased resorption of CSF
Hydrocephalus
Patterns of Hydrocephalus
• Non communicating Hydrocephalus
• Communicating Hydrocephalus.
• A localized obstacle to CSF flow within the
ventricular system causes enlargement of a portion
of the ventricles.
Non communicating Hydrocephalus
Most common is cause of Non communicating Hydrocephalus
masses obstructing
the foramen of Monro or compressing the cerebral aqueduct.
• The entire ventricular system is enlarged
Communicating Hydrocephalus
Common cause Communicating Hydrocephalus
reduced CSF resorption.
sunsetting of the eyes ventricular expansion and
increase intracranial pressure
Hydrocephalus
compensatory increase in CSF volume
(……………………………….) may occur secondary to a loss of brain volume from any underlying cause (e.g., infarction, neurodegenerative disease).
hydrocephalus ex vacuo
Atrophy of parenchyma
displacement of brain tissue from one compartment to another in response to increased intracranial pressure.
Herniation
There are three main herniation
• Subfalcine (cingulate)
• Transtentorial (uncinate)
• Tonsillar
unilateral or asymmetric
expansion of a cerebral hemisphere displaces the…………….. under the edge
of falx.
• associated with compression of the anterior cerebral artery.
cingulate gyrus
Subfalcine (cingulate) herniation
medial aspect of the temporal lobe is compressed against the free margin of the tentorium.
Transtentorial (uncinate) Herniation
temporal lobe is displaced, the third cranial nerve is compromised, resulting in pupillary dilation and impaired ocular movements on the side of the lesion (“blown pupil”). On the affected side , which possibly diagnosis ?
(uncinate) Herniation
Which artery is compressed in Transtentorial ( uncinate ) herniation ?
posterior cerebral artery which affect primary visual cortex
Blown pupil due to
Oculomotor palsy in uncinate herniation
displacement of the cerebellar
tonsils through the foramen magnum.
life-threatening,it causes brain stem compression and compromises vital respiratory and cardiac centers in the medulla.
Tonsillar herniation
If amount of displaced temporal lobe is large enough, the pressure on the midbrain can compress the (……………………)cerebral peduncle against the tentorium, resulting in
(……………………..) (………………………… )to the side of the herniation .
contralateral
hemiparesis
ipsilateral
compression of peduncle causes deformation called
Kernohan’s notch
Progression of transtentorial herniation is often accompanied by linear or flame- shaped hemorrhages in the midbrain and pons, termed ………..
Duret hemorrhages
