Neuropath Lecture 4

Question 1

what are 5 common causes of malformations within neural tissue?

Answer 1

1. virus infections:
   -feline panleukopenia
   -BVD, hog cholera, border disease virus
2. various drugs:
   -griseofulvin (causes encephaloceles)
3. genetic
4. plant toxicities:
   -veratrum californicum
5. nutritional
   -hypervitaminosis A: anencephaly, exencephaly
   -hypovitaminosis A: compression of neural tissue
   -hypocuprosis: cerebellar hypoplasia, hydranencephaly/porencephaly

Question 2

describe neural tube defect

Answer 2

dysraphia: fialure of fusion of neural tube

brain and spinal cord influence development of mesoderm; will see combined defects of brain and cranium and spinal cord and vertebral column

ex: spina bifida, encephalocele

Question 3

describe cerebellar hypoplasia

Answer 3

1. cerebellum does not fully develop ever!
2. causes:
   -viruses: panleukopenia, border disease, BVD, hog cholera
   -genetic
   -hypocuprosis
   -trichlorfon

Question 4

describe the pathogenesis of an in utero infection of feline panleukopenia virus leading to cerebellar hypoplasia

Answer 4

1. parvovirus replicates in cerebellum external granular layer
2. destroys cells destined to be cerebellar neurons
3. results in cerebellar hypoplasia

Question 5

describe cerebellar abiotrophy

Answer 5

1. NORMAL growth followed by progressive degeneration and cell death
   (NOT cerebellar hypoplasia, although may look similar)
2. common in Arab horses in the region of ECA2; DNA testing available

Question 6

describe hydrocephalus

Answer 6

1. abnormal accumulation of CSF
2. can be acquired or congenital (congenital may have a domed skull)
3. can be
   -obstructive: obstruction stops flow and CSF builds up
   OR
   -compensatory: CSF increases to fill gap where parenchyma lost
4. will see atrophy of periventricular white matter and SEPTUM PELLUCIDUM is most sensitive to effects of fluid accumulation!

Question 7

describe hydranencephaly

Answer 7

absence of water causes destruction of parenchyma, causing the ventricles to expand

(different from internal congenital hydrocephalus, where expansion is due to obstruction)

common causes:
1. in utero viral infection
2. hypocuprosis in lambs

Question 8

describe neoplasia in the brain generally

Answer 8

1. can be primary or secondary
2. if secondary, can spread through
   -hematogenous: causes multifocal lesions
   -direct extension: like through cribriform plate

Question 9

what are 6 primary neoplasia of CNS?

Answer 9

1. tumors of mesodermal structures: meninges
2. tumors of glia: astrocytes, oligos
3. tumors of neuroepithelium: ependyma, choroid plexus
4. tumors of primitive neuroepithelium: primitive neuroepithelial tumors (PNET)
5. nephroblastoma of young dogs
6. lymphoma: primary or secondary

Question 10

describe meningiomas

Answer 10

1. in older dogs and cats
2. can also be found in retrobulbar and paranasal sinuses
3. tumors have progesterone, estrogen, and androgen receptors that may influence growth
4. extracranial metastasis is rare but if occurs will go to lungs

Question 11

describe oligodendrogliomas

Answer 11

1. most common parenchymal tumor; in older dogs, esp brachycephalic
2. may break into ventricular system or through surface

Question 12

describe astrocytomas

Answer 12

1. 2nd most common parenchymal tumors, commonly in older dogs
2. can be differentiated (poorly defined and hard to see) or undifferentiated (may appear well demarcated)

Question 13

describe choroid plexus tumors

Answer 13

1. common in older dogs
2. typically benign BUT can cause obstructive hydrocephalus!

Question 14

describe ependymoma

Answer 14

involves the vascular system and can cause obstructive hydrocephalus

Question 15

describe neprhoblastoma

Answer 15

1. intradural, extramedullary spinal cord tumor of YOUNG dogs
2. commonly found between T10-L2

Question 16

describe lymphoma

Answer 16

1. cow and cat most commonly, but also in dogs
   -in cows is BLV associated
2. may be part of multicentric disease but can also occur in primary form in the brain
3. spinal form most common in cats and cows
4. most commonly located epidural in the spinal canal = may be confused with fat!
5. intracranial form usually leptomeninges or choroid, but can be parenchymal

Question 17

describe chordomas

Answer 17

1. common on tails of ferrets
2. derived from intraosseous remnant of notochord
3. slowly enlarge and don’t metastasize but get damaged really easily due to location so often amputate the tail

Question 18

describe cholesterol granulomas

Answer 18

1. common in old horses
2. arise in the choroid plexus
3. usually incidental but may cause obstruction

Question 19

describe nerve sheath tumors

Answer 19

1. in cranial nerves, spinal nerve roots, and peripheral nerves
2. can be benign or malignant
   -but malignant tumors often cause damage due to nerve compression
3. types:
   -schwannoma: benign
   -neurofibroma: benign
   -malignant nerve sheath tumor