Neuropath 1 Flashcards
Most common change of neurons associated with hypoxia/ischemia:
eosinophilic (red) neurons
what is “Nissl substance”?
- granular basophilic material found in NEURONS
- act like a Rough endoplasmic reticulum
what physiological changes cause red neurons?
Loss of ribonucleo-proteins, and denaturation of cytoskeletal proteins
(results in cytoplasmic eosinophilia and nuclear pyknosis )
_________ are the major supporting cells in the brain.
How do these cells respond to injury?
Astrocytes
- Responds to injury by proliferation
______________ (a response to injury from Astrocytes) is analogous to fibrous scar
Reactive gliosis
During reactive gliosis, Astrocyte cytoplasmic processes are highlighted by _______________
glial fibrillary acidic protein (GFAP)
what is the role of oligodendrocytes?
Formation and maintenance of central myelin
injury to oligodendrocytes results in what?
demyelinating diseases
(e.g. multiple sclerosis
_________________ is a neoplasm of oligodendrocytes
oligodendroglioma
__________ cells line the ventricles of the brain.
what is a neoplasm of these cells called?
Ependymal cells
neoplasm = Ependymoma
what do Microglia cells appear as in histo slides? what is their role?
- appear as rod cells
Functions:
- antigen presenting during inflammation
- Neurophagia (eat up neurons) during injury
what is the result of acute neuron damage?
** break down in bloodbrain barrier **
what are Rosenthal fibers ? what produces them? when are they produced?
- Rosenthal fibers = protein aggregates
- made by astrocytes
- response to inflammation
how to microglial cells respond after neural injury?
A) Microglial nodules
B) neurophagia-at injured sites
(Microglia = Bone marrow derived, CNS phagocytes)
what is the Choroid Plexus ? what does it produce? where is it found?
- made of modified EPENDYMAL cells
- Produces cerebrospinal fluid (CSF)
- Intraventricular in location
what is the term for a neoplasm of the Choroid plexus
Choroid plexus PAPILLOMA
_______________ is defined as an increased water content within brain parenchyma .
what can cause this condition
Cerebral Edema (Brain swelling)
- caused by: trauma, hypoxia, tumor, infection
what % of patients with brain injuries have cerebral edema?
75%
Cerebral edema is the major cause of elevated ______________
elevated intracranial pressure
what are the 2 etiologies of Cerebral edema?
1) Vasogenic - Blood-brain barrier disruption and increased vascular permeability
2) Cytotoxic- Increase in water content secondarily to glial or endothelial injury
anatomic signs of Cerebral edema:
Swollen gyri
Compressed sulci
Brain shifting
name the 3 types of brain herniation:
1) Transtentorial (uncal)
2) Cingulate gyral (subfalcine)
3) Cerebellar tonsillar
brain herniation is the result of what?
brain swelling
its defined as: Displacement of brain tissue from one intracranial compartment to another
______________ is defined as the accumulation of excess cerebrospinal fluid within the ventricular system
Hydrocephalus
Causes of Hydrocephalus:
1) Decreased CSF resorption
2) Increased CSF production
what can cause a decrease in CSF resorption?
CSF flow obstructed by:
1) tumor
2) hemorrhage
3) inflammation i.e. meningitis
increased CSF production is a rare condition that is caused by tumors of what location?
tumors of the choroid plexus
ependymal cell cancer
Brain swelling is a major factor contributing to increased _______________
intracranial pressure
what is a papilledema? what causes it?
- papilledema = swelling of the optic disc
- caused by brain swelling
Cerebral edema is the result of excess fluid in brain _____________
parenchyma
parenchyma = neurons & glial cells
why does increased brain volume (from any origin) cause brain damage?
from:
1) decreased perfusion
2) brain tissue displacement
*** brain is in bony case, so it has nowhere to go
________________ diseases are a collective term for pathology of brain vessels
Cerebrovasular Diseases
“Stroke”
what are the 3 categories of cerebrovascular diseases?
1) Thrombus occludes vessel
2) “Moving thrombus” (embolus) occludes vessel.
3) Rupture of blood vessel.
T/F: cerebrovascular diseases can present locally or throughout the brain
true
what are the characteristics of CNS vascular diseases (strokes)?
- acute onset
- non-epileptic patient
- neurological deficit that lasts > 24 hours.
explain the 2 processes that cause strokes:
Hypoxia/ischemia/infarction
- due to impaired blood supply of CNS tissues
Hemorrhage
- rupture of CNS vessels
what are the 3 forms of PRIMARY (non-traumatic) Brain hemorrhage?
- intra-parenchymal hemorrhage
- subarachnoid hemorrhage
- vascular malformations
characteristics of brain infarctions:
- Circumscribed, destructive lesions caused by local interruption of blood flow.
- 70-80% of all cerebrovascular accidents
- Atherosclerosis= most common underlying cause
what is the most common underlying cause of brain infarctions?
Atherosclerosis
what is the most common artery involved in brain infarctions?
Middle Cerebral Artery (MCA)
Effects of Brain infarction after 24-36 hours (acute):
- eosinophilic (red) neurons
- neutrophil infiltration
what occurs 3 days after a brain infarction?
- macrophage infiltration
they have “foamy cytoplasm”
what is the most common cause of Intra-parenchymal Hemorrhages? what site do they usually effect?
- Hypertension most common underlying cause.
- Sites = basal ganglia (most common), also in the Pons
name the clinical effects of intra-parenchymal hemorrhages:
Severe headache
hemiparesis
hemisensory loss
(ONE SIDE loss of motor or sensory)
what is the clinical sign for subarachnoid hemorrhages? what are their characteristics?
- cause SEVERE HEADACHE
- Ruptured saccular ‘berry’ aneurysms
- Most arise at arterial bifurcations of the circle of Willis.
name the most common vasculature malformation that leads to brain hemorrhages:
Arteriovenous malformations (AVM)
= most common
what are the most likely results of an AVM?
likely to result in intraparenchymal and/or subarachnoid bleeds
____________________ are caused by abnormal angiogenesis in developing brain
vascular abnormalities
Characteristics of Epidural Hematoma:
A) cause = Blunt force skull fracture
B) Rupture of a meningeal artery = ARTERIAL bleed
C) “lucid interval”, then progressive loss of consciousness
Characteristics of subdural Hematoma:
- Blood between dura and arachnoid membrane.
- venous bleed
- Acute – whiplash injury, shaken baby syndrome
- Chronic – elderly with brain atrophy.
Do epidural or subdural hematomas spread quicker
EPIDURAL
epi = arterial bleed
- mean you have a lot higher pressure forcing blood into cranium
what are the 3 types of Traumatic Parenchymal Injury ?
1) concussion
2) contusion
3) Laceration
Define concussion, contusion and laceration
A) Concussion – loss of consciousness with full recovery.
B) Contusion – disruption and hemorrhage of superficial brain, caused by blunt trauma
C) Laceration – tearing of brain parenchyma.
Contusions immediately underneath the impact area are called a _________ lesion
“coup” lesion
Contusions developed in a region away from the point of impact are called a _________ lesion
“contrecoup” lesion
what are the 3 main parts of a gun shot wound injury?
1) Entry
2) exit wounds
3) *wound canal *
characteristics of a CHRONIC brain infarction:
A) Softening & liquefaction of parenchyma
B) after 6 months- leads to SMOOTH walled cavities
