Chapter 28: The CNS Flashcards Preview

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Flashcards in Chapter 28: The CNS Deck (144)
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1

Neuronal response to injury within 12-24 hours

Red neurons

Show shrinkage of cell body, pyknosis, loss of nucleolus, loss of nissl substance, with intense eosinophilia of cytoplasm

2

Axonal reaction to injury in which nissl substance is removed from the center of the cell to the periphery

Central chromatolysis


Other axonal reactions to injury include enlarged/rounded cell body, peripheral displacement of nucleus, and enlarged nucleolus

3

Primary example of neuron intracytoplasmic inclusion


What clinical conditions are neuronal intracytoplasmic inclusions seen in?

Lipofuscin

Rabies negri bodies, alzheimer nuerofibrillary tangles, parkinson lewy bodies, CJD

4

Clinical examples of neuronal intranuclear inclusions

Herpes cowdry bodies

CMV has both intranuclear and cytoplasmic inclusions

5

Most important histopathologic indicator of CNS injury, regardless of etiology

Gliosis (astrogliosis)

Characterized by hypertrophy and hyperplasia of astrocytes (now called gemistocytes

6

In what conditions might you see an alzheimer type 2 astrocyte?

Hyperammonemia (chronic liver disease)
Wilson disease
Hereditary metabolic disorder of urea cycle


[characteristics include enlarged nucleus, pale staining central chromatin, intranuclear glycogen droplet, prominent membrane and nucleolus]

7

Thick, elongated, brightly eosinophilic, irregular structures occurring within astrocytic processes and containing 2 heat shock proteins: alpha-B-crystallin and HSP27 as well as ubiquitin

Rosenthal fibers

8

Polyglucosan bodies that are PAS+ associated with increasing age and representative of degenerative change

Corpora amylacea

9

Surface markers of microglia

CR3, CD68 [same as peripheral macrophages]

10

One way in which microglia respond to injury is neuronophagia - what is this process?

Microglia congregate around cell bodies of dying neurons

11

Other glial responses to injury include ________ in PML, which develop intranuclear inclusions

These cells develop glial cytoplasmic inclusions in multiple sytem atrophy (MSA) that contain _________, the product also seen in Parkinsons Lewy bodies

Oligodendrocytes

Alpha-synuclein

12

Response of ciliated ependymal cells (line the ventricles) to injury

Disruption of ependymal lining and proliferation of subependymal astrocytes —> ependymal granulations

[seen in CMV]

13

Difference between vasogenic and cytotoxic cerebral edema

Vasogenic:
Increased extracellular fluid due to BBB disruption and increased vascular permeability; OFTEN FOLLOWS ISCHEMIC INJURY

Cytotoxic:
Increased intracellular fluid secondary to neuronal, glial, or endothelial cell membrane injury; characteristic appearance of flattened gyri, narrowed sulci, compressed ventricles, and potential complication of HERNIATION

14

Responses of the body to increased CSF

Absorption by transventricular and nerve root sleeves

Dilation of frontal and temporal horns

Thinning of cerebral mantle

Stretching/perforation of septum pellucidum

Enlargement of 3rd ventricle downwards

***Increased ICP noted as papilledema***

15

In what condition might hydrocephalus be due to increased production of CSF?

Choroid plexus papilloma

16

What is communicating hydrocephalus?

Communicating (non-obstructive):
CSF is not absorbed properly at the dural sinus level, thus the ventricles tend to be symmetrically dilated

17

What is hydrocephalus ex vacuo? How is this distinguished from other cases of hydrocephalus?

Dilation of ventricles to compensate for shrinkage of brain substance due to other cause (atrophy with age, stroke or other injury, chronic neurodegenerative disease)

CSF pressure is normal in these cases

18

Classic triad of symptoms seen with normal pressure hydrocephalus

“Wet, wobbly, wacky”

Urinary incontinence, gait disturbance (magnetic), dementia

19

3 principle causes of increased ICP

Generalized brain edema

Expanding mass lesion (tumor, abscess, hemorrhage)

Increased CSF volume

20

What are the 3 types of herniation

Subfalcine (cingulate): cingulate gyrus displaced under falx

Transtentorial (uncal): medial aspect of temporal lobe compressed against the tentorium

Tonsillar: cerebllar tonsils displaced through foramen magnum; life threatening due to respiratory and cardiac center compression

21

Which type of herniation involves risk to CN3? What are the effects when CN3 is involved?

Transtentorial (uncal) herniation — dilated pupil and impaired eye movement

22

What is kernohan’s notch phenomenon

Result of compression of cerebellar peduncle against the tentorium cerebelli due to transtentorial herniation

Causes ipsilateral hemiparesis or hemiplegia

[if you have a right hemisphere transtentorial herniation, you have a kernohan’s notch phenomenon in left cerebellar peduncle, which results in right-sided motor impairment]

23

______ = type of hemorrhage in midbrain and pons associated with progression of transtentorial herniation

Duret hemorrhage

24

And infarct in the CNS results in what type of necrosis?

Liquifactive

25

What general pathology accounts for most CNS malformations?

Neural tube defects [usually folate deficiency]

26

Diverticulum of disorganized brain tissue extending through defect in cranium; usually posterior fossa

Encephalocele

27

Conditions associated with microcephaly

Chromosomal abnormalities

Fetal alcohol syndrome

HIV-1

Zika virus

28

What forebrain anomaly is associated with entrapment of meningeal tissue?

Polymicrogyria

29

Neuronal heterotopias are collections of neurons in innappropriate places (i.e., ventricular surface)along the path of migration; commonly associated with what condition?

Epilepsy

30

Changes in Filamin A and DCX proteins on the X-chromosome leads to what anomalies in males vs. females?

Males: lissencephaly

Females: subcortical band heterotopias