Intro CNS/Increased Intracranial pressure Norton Flashcards
How rapidly do nuerons divide
they don’t
- permanent
- postmitotic
name 3 things that cause acute neuronal injury
hypoxic/Ishcemic insult
infectious insult
toxic insult
what happens to neurons in acute neuronal injury
- cell body shrinks
- pyknoisis of nucleus
- cytoplasm intensely eosinophilic
pyknosis
chromatin condenses
what happens to neurons in subacute and chronic neuronal injury
death over long duration
- reactive gliosis - first sign
what is the process of axonal sprouting after axonal injury/transection
- dispersion of Nissl substance to periphery (central Chromatolysis)
- rounding-up
- peripheral displacement of nucleus
- cell death or recovery
what happens to the distal axon in axonal injury
degenerative changes
name 3 things that cause neural inclusions
aging
genetic disorders
viruses
What does aging do to neuronal inclusions
intracytoplasmic lipofuscin
where does herpes effect neurons
intranuclear
where does rabies impact neurons
intracytoplasmic
where does CMV impact neurons
intranuclear and intracytoplasmic
Degenerative diseases deposit where in neuron
intracytoplasmic
What do Alzheimer, parkinson, and Creutzfeldt-Jacob Disease deposit into the neuron
Alzheimer: neurofibrillary tangles
Parkinson: Lewy Bodies
Creutzfeldt-Jacob disease: Abnormal vacuolization
Name 4 types of Glial cells
astrocytes
oligodendrocytes
ependymal cells
microglia
function of astrocyte
barrier function; gliosis
function of oligodendrocytes
form myelin
function of ependymal cells
lines ventricles
function of microglia
fixed macrophages
Astrocytes are found in which matter ( gray or white) in the brain
both gray and white matter
what is gliosis
non-neoplastic proliferation
- indicates CNS injury
- both hypertrophy and hyperplasia
Astrocytes have what fibers in them and describe them
Rosenthal fibers: think eosinophilic
how does astrocyte cellular swelling occur ? what disease is this
failure of PUMP in hypoxia, hypoglycemia, toxins, Creutzfeld-Jakob disease
what is corpora amylacea in astrocytes? what does it indicate and what is a risk factor
- concentrically lamellated
- indicates degenerative change
- increases with age
Alzheimer type II astrocyte is caused by what
hyperammonemia
what can cause injury to Oligodendrocytes
- in dymyelinating disorders
- viral nuclear inclusion may occur in Progressive Multifocal Leukoencephalopathy
what virus may cause extensive ependymal injury
CMV
microglia is derived from what embryology layer
mesoderm
how does microglia respond to injury
- proliferation
- elongating nuclei: rod nuclei
- aggregate around necrotic tissue
- engulf dying neurons; neuronophagia
define vasogenic edema
increased intercellular fluid
what is the most common edema
vasogenic edema
what is cytotoxic edema
increase intracellular fluid
what type of injury would cause cytotixic edema
cell membrane injury ( ischemia)
what kind of damage causes cerebral edema
capillary damage
- disrupted blood-brain barrier
- permeability of new vessels ( tumors )
what would an autopsy of a brain of someone who had cerebral edema look like
brain is soft
- widened gyri
- compressed sulci
what secretes the cerebrospinal fluid
choroid plexus
what is the flow of the CSF
lateral ventricles
- foramen of munro
- 3rd ventricle
- Cerebral aqueduct ( aqueduct of Sylvius)
- 4th ventricle
- foramina of Luschka and Magendie
- Subarachnoid space
- Superior sagittal sinus
who and where does CSF get absorbed
arachnoid villi
superior sagittal sinus
CSF is between what space in the layers of the brain
arachnoid and pia
Hydrocephalus does what to ventricles
dilate them
what causes hydrocephalus
- obstruction of flow
- failure of resorption
- increased secretion: neoplasm of choroid plexus
what happens in non-communicating hydrocephalus
CSF does not pass into subarachnoid space
what are 2 congenital causes of non-communicating hydrocephalus
aqueductal stenosis or atresia
- Dandy-walker syndrome
what are 4 acquired causes of non-communicating hydrocephalus
- neoplasms and cysts
- gliosis of aqueduct
- obstruction of 4th ventricle opening
- organized subarachnoid hemorrhage at base of brain
how does communicating hydrocephalus occur
CSF flows out of ventricular system BUT
- excess CSF
- flow obstructed in subarachnoid space
- reabsorption is reduced
what are causes of communicating hydrocephalus
- choroid plexus papilloma
- deficient absorption of CSF
- -dural sinus thrombosis
- organized subarachnoid hemorrhage
- organized meningitis
- deficiency of arachnoid villi
what happens in normal pressure hydrocephalus
slow dilation of ventricles due to cerebral atrophy
what are clinical symptoms of normal pressure hydrocephalus
- dementia
- gait disturbance
- incontinence
what is the specific definition of increased intracranial pressure
CSF pressure greater than 200mmH2O in lateral decubitus position
what can increased intracranial pressure cause
death from herniation
what can cause increased cranial pressure
obstructive (non-communicating) hydrocephalus
Supratentorial herniation is due to what? displaces what? compresses what?
- unilateral expansion of cerebral hemisphere
- displaces cingulate gyrus under falx cerebri
- compresses anterior cerebral artery
Transtentorial herniation occurs where
uncinate gyrus of temporal lobe through the tentorial opening
what does transtentorial herniation compress? what can this cause
contralateral cerebral peduncle can cause duret hemorrhage may occur in midbrain and pons
- 3rd cranial nerve: unequal pupils
where does Tonsillar herniation occur
cerebellar tonsils through foramen magnum
what does Tonsillar herniation compress
medulla ( death)
what can cause tonsillar herniation
- increased intracranial pressure
- lumbar puncture done
what are 3 clinical signs and symptoms for increased intracranial pressure
- headache
- vomiting
- papilledema
what procedure should not be done for someone who has increased intracranial pressure
NO LUMBAR PUNCTURE
what are 2 physical ways ICP increased can be treated
- remove mass
- shunt
- mechanical ventilation
what chemicals can be used to treat cerebral edema
Mannitol
Corticosteroids
