Intro to Neuropathology part 1 Flashcards
What are the glial cells and what are their shapes?
Astrocytes = oval Oligodendrocytes = round
Set of neurons, not necessarily located together, that share 1+ properties demonstrating response to 1 insult
Selective Vulnerability
Injury response of Neurons to ACUTE injury (12-24 hours)?
“Red neurons”
- Cell shrinkage and pyknosis
- Intense eosinophilic staining
Injury response of Neurons to SUBACUTE and CHRONIC injury (progressive)?
- Reactive gliosis
- Cell loss and Apoptosis
What occurs with the Axonal Reaction of Neurons due to an injury?
Increased protein synthesis + Axonal sprouting
–> displaces nucleus and Nissl substance to the periphery
With the Axonal reaction, what is it called with the Nissl substance is pushed to the periphery?
Central Chromatolysis
Neuronal Inclusions are also a Neuron response to injury. The inclusions can be of what 2 types?
Intranuclear
Intracytoplasmic
What infection can cause Intranuclear Neuronal inclusions and which infection can cause both Intranuclear and Intracytoplasmic?
Intranuclear = Herpes cowdry bodies
BOTH intranuclear and intracytoplasmic = CMV
– everything else = intracytoplasmic
What is the most important indicator of CNS injury?
Gliosis
Gliosis
Hypertrophy and Hyperplasia of ASTROCYTES
What is the job of Astrocytes?
Detoxifiers in the brain
What are Gemistocytes?
Bright pink Astrocytes with displaced nucleus
What are Alzheimers Type 2 Astrocytes?
Astrocytes with a large nucleus, pale stain and intranuclear glycogen droplet
– usually arise with metabolic disorders
What are Rosenthal Fibers?
Elongated bright pink irregular structures within the Astrocytic processes
Where do Rosenthal Fibers usually arise?
In areas of longstanding gliosis!
ex. Pilocytic Astrocytoma
What do Rosenthal Fibers contain?
2 heat shock proteins: alpha B crystalline and HSP27
+ Ubiquitin
Elongated bright pink irregular structures within the Astrocytic processes
Rosenthal Fibers
What is Corpora Amylacea?
Round faint, concentrically laminated strictures adjacent to the Astrocytic end processes
Round concentrically laminated strictures adjacent to Astrocytic end processes
Corpora Amylacea
What does Corpora Amylacea represent?
Degenerative change
– Increased # with Increased age
What is contained within Corpora Amylacea and what marker is (+)?
(+) PAS
- Polyglucosan bodies, 2 heat shock proteins, Ubiquitin
What are Microglia and what surface markers are (+)?
Macrophages of the CNS
(+) CR3 and CD68
What are 2 possible injury responses of Microglia?
- Microglial Nodules
2. Neuronophagia
Microglial Nodules
Microglia aggregate around small foci of necrosis
Neuronophagia
Microglial congregate around cell bodies of dying neurons
Where and what type of cells are Ependymal Cells?
Ciliated cells that line the ventricles in the brain
What is an example of an infection that can injure Ependymal Cells and describe what occurs?
CMV
- Ependymal Granulations
What is one injury response of Oligodendrocytes?
Demyelination
Cerebral Edema
Accumulation of fluid in the brain parenchyma
What are the 2 types of Cerebral Edema?
– Commonly occur together
- Vasogenic Edema
2. Cytotoxic Edema
Vasogenic Edema and what causes it?
Increased EXTRAcellular fluid due to BBB disruption and increased vascular permeability
– usually follows an ischemic injury
Cytotoxic Edema and what causes it?
Increased Intracellular fluid due to neuronal/glial/endothelial cell injuries
– Can follow ischemic or metabolic derangement
What changes can occur to the actual brain (gyri, sulci, ventricles) with Cerebral Edema?
Gyri flattened
Sulci narrowed
Ventricles compressed
– Can lead to herniation
Hydrocephalus
Increased ventricular volume due to increased CSF
“True” Hydrocephalus
Frontal horns > 1/2 internal skull diameter
If “True” Hydrocephalus is not present, what is likely occuring?
Hydrocephalus ex-vacuo = atrophy of the brain
Describe Hydrocephalus ex - vacuo
Atrophy of the brain with decreased brain substance + hydrocephalus
- CSF pressure = NORMAL *
- Can be caused by age, stroke, neurodegenerative disease
What are the general 2 causes of Hydrocephalus?
- Obstruction - clot, tumors, stenosis, infections
2. Increased CSF production - Choroid Plexus Papilloma (thick fibrous stalk)
How do TB and Neurosyphilis cause Obstructive Hydrocephalus?
- Pyogenic Meningitis = suppurative exudate covering brainstem/cerebellum
- Thickened Leptomeninges
- Obstructive Hydrocephalus
Communicating Hydrocephalus
CSF NOT properly absorbed at the dural sinus level
=> ventricles are symmetrically dilated
With Communicating Hydrocephalus, is there a single point of obstruction?
NO
- CSF not properly absorbed at the dural sinus level
What is Normal Pressure Hydrocephalus?
CSF drainage is blocked gradually in older people
–> Symmetric hydrocephalus
What are the symptoms of Normal Pressure Hydrocephalus?
” wet, wacky, wobbly “
- UI
- Dementia – troubles with recall
- Magnetic gait – feet stuck to the floor
UI, dementia and gait disturbances could indicate?
Normal Pressure Hydrocephalus
Why is it important to properly diagnose Normal Pressure Hydrocephalus?
It is reversible!
As the Intracranial Volume increases, what compensates so the Intracranial pressure does not increase dramatically?
Venous system can compress and displace CSF
There is a certain point where a small increase in the intracranial volume correlates with a LARGE increase in intracranial pressure. What usually occurs after that?
Brain tissue HERNIATION
What things can cause Increased Intracranial Pressure?
- Generalized brain edema
- Expanding mass lesion
- Increased CSF volume
Subfalcine Herniation
Cingulate gyrus displaced under Falx
Transtentorial Herniation
Medial temporal lobe compressed against Tentorium
What are the signs of Transtentorial Hernation?
CN3 => Dilated pupil and impaired eye movement
Tonsillar Herniation
Cerebellar tonsils displaced through Foramen Magnum
What are the signs of Tonsillar Hernation?
Respiratory and Cardiac center compression
What are the main symptoms of Increased Intracranial Pressure?
Papilledema
Headache
N/V
Seizures, lethargy, etc.
Describe Kernohan’s Notch Phenomenon
- Transtentorial Hernation
- Contralateral Cerebral Peduncle compressed against tentorium which produces a “notch” in the peduncle
=> Ipsilateral hemiparesis on side of herniation
Describe what will occur if there is Right hemisphere transtentorial herniation with the Kernohan’s notch phenomonen?
- Right hemisphere transtentorial herniation
- -> Left cerebral peduncle notch
- -> Right sided hemiparesis (motor impairment) and possible blown pupil
As a Transtentorial herniation progresses, what lesions may accompany it?
Duret Hemorrhage
– Hemorrhagic lesions in midbrain and pons