CNS Pathology

Question 1

Brain necrosis

Answer 1

Liquefactive

Question 2

Acute neuronal injury

Answer 2

Red neuron

Morphology:
Cell body shrinks
Pyknosis of nucleus
Cytoplasm intensely eosinophilic

Question 3

Axonal sprouting after axonal injury

Answer 3

1. Dispersion of Nissl substance to the periphery (central chromatolysis)
2. Rounding up
3. Peripheral displacement of nucleus
4. Cell death or cell recovery

Question 4

Axonal injury

Answer 4

Axonal sprouting of proximal axon

Distal axon undergoes degenerative changes

Question 5

Aging

Answer 5

Intracytoplasmic lipofuscin

Question 6

Herpes

Answer 6

Intranuclear inclusions

Cowdry A inclusion

Question 7

Rabies

Answer 7

Intracytoplasmic inclusions

Negri body

Question 8

CMV

Answer 8

Intranuclear and intracytoplasmic inclusions

Question 9

Ependymal cell secretion

Answer 9

CSF

Question 10

Astrocytes

Answer 10

Found in both gray and white matter

Question 11

Gliosis

Answer 11

Non-neoplastic proliferation of astrocytes

Most important histopathologic indicator of CNS injury
Both hypertrophy and hyperplasia
Stains for GFAP

Question 12

Rosenthal Fibers

Answer 12

Thick eosinophilic

Long standing gliosis
Cerebellar pilocytic astrocytoma

Question 13

Corpora Amylacea

Answer 13

Concentrically lamellated
Indicates degenerative change
Increase with age

Astrocytes

Question 14

Alzheimer type II astrocyte

Answer 14

Long standing hyperammonemia

Question 15

Ependymal cells

Answer 15

CMV may cause:
Extensive ependymal injury
Viral inclusions

Question 16

Microglia response to injury

Answer 16

Proliferation

Elongating nuclei- rod cell

Aggregate around necrotic tissue- microglial nodules

Engulf dying neurons- neuronophagia

Question 17

Vasogenic edema

Answer 17

Increase intercellular fluid

Resorption impaired because of paucity of lymphatics

Question 18

Cytotoxic edema

Answer 18

Increase intracellular fluid

Question 19

Flow of CSF

Answer 19

1. Lateral ventricles
2. Foremen of Munro
3. 3rd ventricle
4. Aqueduct of Sylvius in midbrain
5. 4th ventricle
6. Foramina of Luschka and Magendie
7. Subarachnoid space
8. Superior Sagittal sinus

Question 20

Hydrocephalus

Answer 20

Excessive CSF in ventricular system

Question 21

Non-communicating hydrocephalus

Answer 21

CSF does not pass into subarachnoid space

Congenital:
Aqueductal stenosis or atresia
Dandy-Walker syndrome

Acquired:
Neoplasms and cysts
Gliosis of aqueduct
Obstruction of 4th ventricle
Organized subarachnoid hemorrhage at base of brain

Question 22

Communicating hydrocephalus

Answer 22

CSF flows out of ventricular system but…
Excess CSF
Flow obstructed in subarachnoid space
Reabsorption is reduced

Choroid plexus papilloma

Question 23

Normal pressure hydrocephalus

Answer 23

Slow dilation of ventricles due to cerebral atrophy
Free flow of CSF
Dementia, gait disturbance, incontinence

Question 24

Supratentorial herniation

Answer 24

Subfalcine

Due to unilateral expansion of cerebral hemisphere
Displace cingulate gyrus under falx cerebri
Compresses anterior cerebral artery

Question 25

Transtentorial herniation

Answer 25

Uncinate gyrus of temporal lobe through the tentorial opening
3rd cranial nerve-unequal pupils
Compress contralateral cerebral peduncle- ipsilateral hemiparesis
Duret hemorrhage may occur

Question 26

Tonsillar herniation

Answer 26

Cerebellar tonsils through foramen magnum

Medulla compressed- death