Basic Reactions, Edema, Herniation Flashcards
Excess CSF within the cranial cavity due to decreased outflow of CSF, resulting in enlargement of one or more ventricles; further classified as either communicating or noncommunicating depending on where obstruction is
Hydrocephalus
_________ hydrocephalus is due to obstruction within ventricles (cerebral aqueduct)
_________ hydrocephalus is due to obstruction in Subarachnoid space or villi
Non-communicating
Communicating
Ventriculomegaly that results secondarily from a loss of brain tissue (brain atrophy)
Hydrocephalus ex vacuo
Common causes of Hydrocephalus
Aqueduct Stenosis (congenitally or acquired stenosis of cerebral aqueduct)
Dandy-Walker malformation (a hindbrain malformation causing cystic dilatation of 4th ventricle)
Chiari II malformation (a hindbrain malformation)
Post-Inflammatory/Hemorrhagic (blockage due to inflammatory cells or hemorrhage)
Tumors
Barrier that controls the extracellular environment of the brain by regulating the movement of molecules from blood; keeps out infectious agents and may impede drug delivery to brain and CSF; lipid-soluble molecules are not restricted
Blood-Brain Barrier
How can the breakdown of the BBB occur
Inflammation; Tumors; infarcts; Trauma
Breakdown of the BBB results in inc. vascular permeability, leading to an increase in __________ detectable by lumbar puncture (LP)
CSF protein
An increase of brain volume due to increased fluid (not ventricles); can be either extra/intracellular fluid; can be due to trauma, infarcts, tumors, infections, water intoxication, etc.; can result in MASS EFFECT
Brain Edema
Type of Brain Edema; EXTRACELLULAR edema due to inc. permeability of brain capillaries (BBB breakdown); mainly in WHITE matter
Vasogenic brain edema
Vasogenic edema is typically in the (white/gray) matter
White
Type of Brain Edema; INTRACELLULAR edema due to osmotic imbalance between the cell and extracellular fluid; mainly in the GRAY matter
Cytotoxic brain edema
Cytotoxic edema is typically in the (white/gray) matter
Gray
Type of Brain Edema; EXTRACELLULAR edema in the periventricular WHITE matter
Interstitial (hydrocephalic) brain edema
Hypothesis that states that the skull is a closed system. Therefore, the CSF, blood, and brain tissue inside of it must remain at a relatively constant volume. Any increase in volume of one component means that other components must be reduced in volume to not increase pressure.
Monro-Kellie hypothesis
Cerebral Perfusion Pressure (CPP) can be measured by what formula?
Mean Arterial Pressure - Mean ICP
- As ICP increases, the CPP decreases (which can lead to brain ischemia)
Finding on fundoscopy for increased ICP
Papilledema (swelling of optic disc)
What can cause increased ICP
Masses (tumor, abscess, hematoma, etc.) Hydrocephalus Brain Edema (trauma, meningitis, encephalopathy, etc.) Obstruction (of dural venous sinuses) Idiopathic Intracranial HTN
herniation caused by horizontal (left-to-right) midline shift; may compress the Anterior cerebral artery
Subfalcine herniation
the movement of brain tissue from one intracranial compartment to another; herniation of either uncal (medial temporal lobe) or central (diencephalon) compresses the upper brainstem; may compress the Posterior cerebral artery
Transtentorial Herniation
Brain herniation through the foramen magnum compressing the medulla
Tonsilar Herniation
A dilated ipsilateral pupil and contralateral hemiplegia (paralysis of one side of body) can be due to a _______ herniation
uncal
Stain that can show myelin sheaths surrounding individual axons
Luxol Fast Blue stain
How can an intracranial mass result in brain ischemia and death
Intracranial mass –> Inc. ICP –> dec. CPP –> ischemia
Intracranial mass –> brain herniation –> brainstem compression –> death
