CNS Flashcards
(235 cards)
1
Q
List the Neural tube closure defects (dysraphia)
A
- Anencephaly and prosencephalic hypoplasia
- Meningoencephalocele and cranium bifidum
- Meningomyelocele and spina bifida
- Hydromyelia
2
Q
what is the term for total abscence of the brain
A
Anencephaly
the term is used even though a small portion of the
brain persists
– often the medulla is present and occasionally some of
the mesencephalon
3
Q
What are the lesions of anencephaly
A
- absence of the cerebral hemispheres
- failure of forebrain fusion
4
Q
Prosencephalic hypoplasia is common in which animals
A
pigs and lambs
5
Q
failure of bilateral separation of the primitive single telencephalic cavity into two hemispheres
A
- cerebral aplasia(procencephalic hypoplasia)
- there is absence of the cerebral hemispheres
6
Q
what are the lesions of proncephalic hypoplasia
A
- a single central ventricle
- absence of the longitudinal fissure, the corpus
- callosum, olfactory bulb and optic tracts
- brain stem and cerebellum are normal
- associated with cyclopia
7
Q
protrusion of the brain (along with the meninges)
through a defect in the cranium (cranium bifidum)
A
Encephalocele
related to suture lines
– almost always median
– the skin forms the hernia sac
– spinal bifida refers to the defect in the spine
8
Q
protrusion of the fluid filled
meninges
A
- meningocele
- it is fluid filled
- miningocele and enencephalocele can be inherite in bothpgs and brunnete cats and has been associated with treatment of griseofuscin in pregnant queen
9
Q
define microencephaly
A
- it is an abnormally small brain
- cerebrum is mostly affected
- is a defect in cerebral corticogenesis due to decreased migration of germinal epithelial cells
10
Q
defect in cerebral corticogenesis due to increased migration of germinal epithelial cells (errosrs of cerbal gyri)
A
macroencephaly
11
Q
which area of the brain is most affected by microencephaly
A
cerebrum
deficiency of cerebral gray and white matter
12
Q
abnormally flattened and narrowed frontal part
of the cranium with frontal bones thicker than normal are lesions of……..
A
Microencephaly
13
Q
list the viruses that causes Microencephaly
A
- Akabane virus in lambs
- BVD virus in calves
- Border disease virus in lambs
- Hog cholera virus in piglets
14
Q
abnormally large brain or excessive volume of the
intracranial contents
A
Macroencephaly (megalencephaly)
tend to be asymmetrical with exaggerated degrees
of heterotopia (displacement of an organ from its
normal position)
15
Q
presence of clusters of
nerve cells at a site where they are normally
absent (e.g., subcortical white matter)
A
Cortical dysplasia
incomplete migration of neuroblasts during
fetal life
• usually associated with dysplastic development of
the cortex
16
Q
lack of formation of secondary or tertiary gyri
A
- Macrogyri
- large, smooth gyri analogous to those of the brains of lower organisms are formed
- dysplasia and distortion of cortical architecture
17
Q
congenital anomality with small numerous convulutions
A
Microgyria (polymicrogyria)
normal gyral pattern is lost in affected areas
18
Q
what are the lesions of microgyria
A
- asymmetrical or patchy
- abruptly demarcated from normal cortex
19
Q
discuss morphological characteristics of Ulegyria
A
- imparts a wrinckled appearence to the cortex
- it arises as a consequence of scarring and atrophy to otherwise topographically normal gyri
- there is focal laminar necrosis caused by prolonged ischemia /anoxc injury in the perinatal period
20
Q
convulations almost absesnt in
A
Lissencephaly (agyria)
there is absence of primary gyri
brain surface is almost perfect smooth
excessively thin membrane
21
Q
what are the morphological characteristics of lissencephaly
A
- there is absence of primary gyri
- brain surface is almost perfect smooth
- excessively thin membrane
22
Q
what causes lissencephaly
A
defective neuronal migration
23
Q
lissencephaly occurs in which dog breed
A
Lhasa Apso dogs
24
Q
excessively broad brain convolutions result in which cerebral corticogenesis defect
A
Pachygyria (macrogyria)
25
Pachygyria (macrogyria) lesions
* Excessive broad brain convulsions resulting from fewer secondary gyri
* increased depth of the gray matter underlying the smooth part of the cortex
26
abnormal accumulation of fluid in the ventricles of
the brain and sub-meningeally
hydrocephalus
27
internal hydrocephalus is common in which animals
brachycephalic breeds and in aged animals
28
hydrocephalus in which fluid accumulates in the ventricles
internal hydrocephalus
29
hydrocephalus in which fluid accumulates in the sub-arachnoid space
external hydrocephalus
30
etiology of Congenital hydrocephalus
* idiopathic
* intra-uterine viral infections
* nutritional deficiencies
* familial in pigs
* malformation of the cranium
obstruction mostly develops as the consequence of a
periductal gliosis of the aqueduct of Sylvius
31
what are the lesions of congenital hydrocephalus
* dilated ventricles or the duct system
• dome-shaped, thin-boned and enlarged cranium
32
discuss Acquired hydrocephalus
* seen most commonly as an internal hydrocephalus
* obstruction of flow due to an accumulation of and organization of exudate
* progressive
* ** no malformation of the cranium**
33
Acquired hydrocephalus etiopathogenesis
* bacterial meningitis
– most cases are acutely fatal
* granulomatous meningitis
– TB, cryptococcosis, FIP
* intracranial neoplasms
* parasitic cysts
* cholesteatoma (cholesterolinic granuloma) in
horses
34
what are the lesions of acquired hydrocephaly
* may be difficult to observe in neonates where the brain is soft and easily collapses
* pressure atrophy of the septum pellucidum and hippocampus
* ventricular dilatation
* pressure atrophy of cerebrocortical white matter
35
• Encephaloclastic defects
destructive lesions of the
brain
36
types of Encephaloclastic defects
* Hydranencephaly (diffuse)
* Porencephaly (focal)
37
complete or almost complete absence of the cerebral
hemispheres in a cranium of normal size and
formation
Hydranencephaly
38
discuss leptomeninges
* normal position
* form sacs enclosing CSF (the fluid occupies space normally occupied by the parenchyma)
39
residual lesion of full-thickness necrosis of the
cerebral hemisphere associated with fetal viral
infections
Hydranencephaly
40
which congenital cranial defect is common in calves in association with cerebellar hypoplasia
•and can also be found in lambs of ewes vaccinated during pregnancy for
bluetongue
Hydranencephaly
•and can also be found in lambs of ewes vaccinated during pregnancy for bluetongue
41
cysts or cavities in the wall of the cerebral
hemisphere (cystic cavitation of the brain)
**Porencephaly**
* typically involves the white matter of the cerebral hemispheres
* cyst communicates with the subarachnoid space and or lateral ventricle
42
etiogenesis of porencephaly
* congenital anomaly
* remnants of destructive lesions
– viral infections (Border disease, hairy shaker
disease, BVD)
43
which parasite can cause similiar lesions as porencephaly
taenia multiceps
44
what causes cerebral hypoplasia
* usually following intra-uterine viral infections
1. feline panleukopenia \>\> ataxia in kittens
2. BVD/MD
3. hog cholera vaccination
4. Border disease
5. rat virus, hamster osteolytic virus
* can be inherited
45
what are the gross lesions of Cerebellar hypoplasia
* normal in size and appearance or small nubbin of tissue
* lack of normal development of the layers of the cerebelum
46
microscopic lesions of Cerebellar hypoplasia
* loss of purkinje cells
* granular layer narrowed and deficient in cells
* molecular layer usually normal
47
premature or accelerated degeneration of formed
elements of the cerebellum
cerebellar atrophy
48
discuss characteristics of cerebellar atrophy
* Purkinje cells appear particularly susceptible
* lambs (“daft lambs” in England and Canada)
* dogs
* cats
* various breeds of cattle, piglets, and foals
* **degeneration and loss of Purkinje cells and granule ****cells **
49
11 week old blue terrier is presented with ataxia and dysmetria .which inheritive cranial disease o you suspect
## Footnote
**Hereditary striatonigral and cerebello-olivary degeneration**
seen between 9 and 16 weeks of age
50
Purkinje cell axonal swelling in the cerebellar granular layer + degeneration and loss of Purkinje cells are all lesions of
**Bovine familial convulsions and ataxia**
* it is heritable disorder of purebred and crossbred Aberdeen Angus cattle in the UK
* clinicalsigns are episodic suizuresin new born and young calvesand granual development of ataxia with spasticity and hypermetria in calves surviving bouts of suizures extending over 2-3 months
51
what are the clinical signs of bovine familial convulsions and ataxia
* intermittent episodic seizures in newborn and young calves
• gradual development of ataxia with spasticity and
hypermetria in calves surviving bouts of seizures
extending over 2-3 months
52
cerebellar degeneration and ataxia of horses in New
Caledonia
Gomen disease
53
lesions of gomen disease
* folial atrophy in the cerebellar vermis
* thinning of the cerebellar molecular layer and loss of Purkinje and granule cells
* deposition of a pigment resembling lipofuscin in many of the surviving Purkinje cells and in the neurons of the brain and spinal cord
54
displacement of the tongue of the cerebellar vermis, medulla and caudal 4th ventricle through the foramen magnum into the spinal canal
**Arnold-Chiari malformation**
* a developmental defect of the cerebellum and brain stem associated with hydrocephalus
55
discuss Dandy-Walker syndrome
* it isa midline defect of the cerebellum where vermis is largely absent
– cerebellar hemispheres widely separated by a
large fluid-filled cyst in an enlarged caudal
fossa
* roof of the cyst consists of ependyma, a disorganized layer of glial tissue, and an outer layer of leptomeningeal
tissue
– an expanded 4th ventricle forms the floor of
the cyst
56
total absence of the spinal cord
Amyelia
usually associated with anencephaly
57
Segmental aplasia and hypoplasia of the spinal cord
Myelodysplasia
* lumbar region most frequently affected
• some cases are associated with fetal Akabane
virus infection
58
discuss Perosomus elumbus in calves and lambs
* Myelodysplasia
* partial agenesis of the spinal cord and there is failure of induction of the related vertebrae
* cranial part of the body is normal
* _ vertebral axis ends at the caudal thoracic region_
* lumbar, sacral, and coccygeal vertebrae areabsent
* spinal cord ends in the thoracic region in a blind vertebral canal
* caudal part of the body remains attached to the cranial part by soft tissue only
* arthrogryposis limbs
* muscular atrophy
59
spinal cord ends in the thoracic region in a blind vertebral canal and caudal part of the body remains attached to the cranial part by soft tissue only
Perosomus elumbus in calves and lambs
60
```
tubular cavitation (syrinx) of the spinal cord
extending over several segments
```
Syringomyelia
61
Weimaraner is presented with the clinical signs below, what do you suspect
* affected dogs are unable to completely extend the hind limbs
* crouched posture
* hind limbs are moved together in progression
(symmetrical hopping gait)
**Syringomyelia**
lesions are not observed until about the 8th month
of life
62
gross lesions of Syringomyelia
* cavitations in the lumbar segments
* may or may not be visible to the naked eye
63
microscopic lesions of syringomyelia
* cavitations in the central gray matter (dorsal and
lateral to the central canal)
* not lined by ependymal cells
64
simple dilatation of the central canal of the spinal
cord
Hydromyelia
the cavity is connected with the central canal and lined by ependymal cells
65
a syndrome of pelvic limb gait disturbance in young
dogs (“bunny-hopping” or “kangaroo-gait”)
Myelodysplastic and dysraphic lesions in Weimaraner
dogs
inherited in a co-dominant mode with variable
penetrance
• lethal in the homozygous state
66
lesions of Myelodysplastic and dysraphic lesions in Weimaraner dogs
* **a range of dysraphic defects:**
* anomalies of the dorsal septum (may be absent)
* hydromyelia
* duplication or displacement of the central canal
* anomalies of extent and distribution of the central gray matter
* anomalies of the ventral horns
* deficiency of the ventral median fissure
* ± thoraco-lumbar scoliosis, depression of the sternum, abnormal hair streams in the dorsal cervical region
67
pathogenesis of Myelodysplastic and dysraphic lesions in Weimaraner dogs
primary lesion is related to aberrantly positioned
mantle cells ventral to the central canal in the
floor plate area
68
absence of the dorsal portions of the vertebrae
Spina bifida
69
spina bifida is mostly found in which animals
* this defect occurs most frequently in
brachycepahlic breeds of dogs and is inherited
in Manx cats
sacrococcygeal agenesis occurs in association
with spina bifida in Manx cats, claves, dogs, and
sheep
70
a condition where neurulation does not occur,
the neural plate remaining open; the defect involves
the whole of the vertebral axis with
anencephaly an expected accompaniment;
there is virtual amyelia , neural tissue
being present only as soft red masses in
the residual groove
**Total myeloschisis**
* a type of spinal bifida
* local myeloschisis is a localized defect due to failure of closure of the neural tube
71
a cystic swelling protrudes through the
vertebral defect i.e
Spina bifida cystica
example is when meninges protrude (meningocele),
the roof of the cyst comprises skin and
condensed meninges, including dura mater
72
discuss Spina bifida with meningomyelocele
* the cyst tends to be broad-based
* failure of dehiscence of the neural crest from surface ectoderm provides for a central area without epithelial covering
73
lesions of dermoid sinus in Rhodesian Ridgeback dogs
* incomplete separation of the neural tube from the overlying dorsal midline ectoderm allows persistence of a sinus connecting the skin surface to the supraspinatus ligament,
* or it may extend as deep as the dura mater of the spinal cord
74
what are the viruses associated with congenital malformations in calves
BVD
BD
75
what are the viruses associated with congenital malformations in LAMBS
* vaccination
– RVF, bluetongue
* Wesselsbron disease
– natural infection and vaccination
* Border disease
76
list diases that causes intracytoplasmic neuronal vacuolization
1. scrapie
2. bovine spongiform encephalopathy(BSE)
3. toxicity)→solanum spp, myotoxicosis,aspirgillus, clavatus
77
disappearance of the nissel substances from the cell body
chromocytolysis
it is associate with cytoplasmic swelling
78
characteristics of chromatolysis
* irregular vacuolation of the neutrophil
* restricted to white matter and nerve
* moth eaten appearance, status spongioform
* reduced staining capacity of the affected tissue→rarefaction
79
loss of myelin due to disoders of myelin in supporting cells such as schwann and oligodendritic cells
primary demyelination
80
give an example of a secondary demyelination
wallerian degeneration
* it follows a severe axonal damage.
* it reflects death of an exon
81
describe wallerian degeneration
1. axon and myelin are disrupted at the point of injury and the fiber dies back several nodes and the distal section dies
2. then fragmentation of the axon and sheath occurs in a few days
3. debris are then removed by phagocytosis within a few weeks
82
hereditary or congenital defects of Cu def. in lambs (swayback)
dysmyelination and dysmyelinogenesisis
83
the condition whare myelination is not complete at birth
nota bene
84
what are the clinical signs of nota bela in neonates with incomplete myelination at birth
1. neonates cannot walk
2. brain is very soft with severe brain edema
85
what are the clinical sings of neonates with nearly complete myelination at birth
allows neonates to run(foals)
86
edema of the myelin and disruption at the intraperiod line of the myelin sheath
spongioform myelinopathies
87
list the familial or heditory disease
1. primary neuronal degeneration
2. spongy degeneration
3. mitochondrial encephalopathy
4. degenerative myelopathy
88
what causes abiotrophy neurodegeneration
* it is a primary premature neuronal degeneration
* it is not secondary to toxin or infectious agents
*
89
an arabian horse gets ataxic and dysmetria before maturity. which disease do you suspect
cerebellar abiotrophy
* it also affects dogs
* it is distinct from cerebellar hypoplasia
* affected animals appear normal after birth
90
cerebellum can be normal or shrunken in which disease
cerebellar abiotrophy
91
what are the lesions of cerebellar abiotrophy
cerebellum can be normal or shrunken
92
what are the histological lesions of cerebellar abiotrophy
* neuronal degenraration and loss
* reactive gliosis ( production of dense fibrous network of neuroglia in areas of damage)
93
lesions of neuroxonal dystrophy
axonal swelling of the brain stem, cerebellum and spinal cord
94
axonal degeneration and secondary demyelination in the white matter of the spinal cord
degenerative leukomyelopathy
95
discuss changes seen in acute nerve necrosis
* initial degeneration
* neuronal swelling central dissolution of nissel substance
n.bas long as the cell body is intact then damage is reversible
96
discuss acute nerve necrosis due to damaging injury
* condensation of the cytoplasm
* **intennse cytoplasmic eosinophilia of the neuron**
* the nucleus becomes pyknoticand the entire cell may fragmentand get phagocytised
97
what causes acute nerve necrosis
* ischemia
* acute toxicity
* infection
98
this type of nerve degeneration is seen as cellular atrophy and hyperchromasia or by the presence of cytoplasmic vacuolizationand increase intracellular filaments and proteins
chronic nerve degeneration
99
what are the characteristics of chronic nerve cell injury
* cellular atrophy and hyperchromasia
* cytoplasmic vacuolization
* increased intracellula filaments and proteins
* further injury⇒ contraction of the cell body, the cytoplasm becomes basophilic rather than eisinophilic.
* prolonged injury⇒nucler pyknosis and fragmentation
100
pale areas in neuronal cytoplasm due to dispersion of nissle substances
chromatolysis
101
destruction of axon and myelin sheath following trauma or toxic injury
wallerian degeneration
102
accumulation of glial cells around damaged neurons
satellitosis
103
accumulation of polymorphonuclear (supperative) or mononuclear (non supperative)leukocytes in perivascular spaces
perivascular cuffing
104
thin,whittish mottled red enlongated plates often containing bone marrow
cerebral and spinal dural metaplasia
it causes pressure on the spinal cord and nerve roots resulting in wallerian degeneration
105
what is the condition where there is failure of bilateral separaton of the primitive telecenphalic cavity into 2 hemispheres and there is absence of the cerebral hemispheres
cerebral aplasia
106
what are the characteristic lesions of cerebral aplasia
* absence of cerebral hemispheres
* there is a single central ventricle
* **abscence o**f
* the longitudinal fissure,
* corpus collosum,
* olfactory bulb
* optic tracts
* severe cases may have central proboscis and a single eye
107
potrution of the of the brain through a defect in the cranium
encephalocele
it is related to the suture lines and are almost always median, the skin forms the hernia sac
108
portrution of the fluid filled meninges
meningocele
109
a pregnant queen was treated with griseofuscin. what are you mostly concerned with
encencephaly and meningiocele
110
what is macrogyri
lack of formation of secondary or tertiary gyri
111
what are the lesions of macrogyri
large,smooth gyri analogy with those of the brains of lower organisms
there is dysplasia and distorsion of cortical architecture
112
abscence of primary gyri
lissencephaly (agyria)
convulsions are almost entirely absent and the brain surface may be smooth (smooth brain) eccept for slight grooves in which the meningeal surfaces are situated
113
what are the lesions of lissencephaly
* convulsions are almost entirely absent
* the cerebral cortex is extremely thin
* etiopathogenesis:defective neuronal migration
* occurs in lhasa Apso dogs
114
what causes lissencephaly
defective neuronal migration
115
what causes cyclopia
* idiopathic
* chromosomal anomalies
* prolonged gestation in guersey and jersey fetuses
* veraturum califonicam
*
116
fluids builds in the ventricles
internal hydrocephalus
117
fluids accumulates in the sub-arachnoid space
external hydrocephalus
118
complete or almost complete absence of the cerebral hemispheres leaving only membraneous sacs filled with CSFand enclosed leptoleptomengitis
hydranencephaly
119
how does hydranencephaly differ from hydrocephalus
* the cranial cavity is complte in contrast to hydrocephalus and of normal comformation
* the leptominingis are in their normal positions and form sacs enclosing the CSF
* the cerebral hemispheres are largely represented by large cystic spaces or sacs.
* there is no ependymal lining
120
give examples of hydranencephaly in anmals
* mostly commonly observe in calves with cerebral hypoplasia
* lambs of ewes vaccionated uring pregnancy for bluetongue
* hydrancencephaly is a residual lesion of full thickness necrosis of the cerebral hemisphere usually associated with fetal viral infections eg akabane virus
121
cystic cavitation of the brain evolving from a destructive process in prenatal life
**porencephaly**
* the defect typically involves the white matter of the cerebral hemispheres.the naffected brain may contain a single cyst or there may be multiple cystic lesions.
* the cyst may communicate with the ventricular cavities or with the subrachnoid space
122
what causes porencephaly
same as hydracephaly
. uterine virus such as BVD
123
what causes cerebellar hypoplasia
1. inherited in chowchow etc
2. viruses
* feline pannleukopenia virus
* herpes virus in dogs
124
what are the lesions of cerebellar hypoplasia
* decrease in size of the cerebellum
* with lack of development of the layers of the cerebellum
125
what are the microscopic lesions of cerebellar atrophy
degeneration and loss of purkinje cells and granules
126
what causes cerebellar atrophy
intrinsic metabollic defect
127
a 10 week old blue kerry terrier is presented with a history of ataxia and dysmetria .what disease should be top of your differential
hereditary striatonigral and cerebello-olivary degeneration
128
a tubular cavitation of the spinal cord which extends over several segments
syringomyelia
129
gross lesions of syringomyelia
cavitations are usually found in the lumbar segments and they may or may not be visible to the naked eye.
130
what are the microscopic lesions of syringomyelia
the cavitations are usually found in the central gray matter and they are not line by ependymal cells
131
dilation of the central canal of the spinal cord
hydromyelia
the cavity is connected with the central canal and lined by ependymal cells.
132
a waimaraners has a pelvic limb gait disturbance which is characterised by bunny hopping or kangaroo gait. which isease do you suspect
myelodysplastic and dysraphic lesion
133
what are the lesions of myelodysplastic and dysraphic
* anomalies of the dorsal septum which may be absent
* hydromyelia
* duplication or displacement of the central canal
* anomalies of extent and distribution of the central gray matter
* anomalies of the ventral horn
* def. of the sternum
* abnormal hair streams in the dorsal cervical region
134
what are the lesions of prion diesease
characterised by
* spongiform change of the neuropil
* neuronal degeneration
* apoptosis and loss
* astrocytosis
* formation of prominent cytoplasmic vacuoles
135
where are histolic lesions of prion diseases found
brainstem espercially obex
136
inherited deficiency of the catabolic enzyme galactocerebroside-B-galactosidase
globoid cell leukodystrophy
137
what is the lesion observed in globoid cell leukodystrophy
macrophages(microglial cell) are transformed into globoid cells when PAS positive inclusion tubules of galactocerebroside accumulate within them
138
what are the gross lesions of globoid cell leukodystrophy
regions of fixed white matter are gray and soft compared to normal white matter
139
necrosis of the white matter
leukomalacia
140
necrosis of the gray matter
poliomalacia
141
necrosis of the brain as a whole
encephalomalacia
142
necrosis of the spinal cord
myelomalacia
143
necrosis of the brain and spinal cord
encelomyelomalasia
144
what type of lesions do you find in hypoxia
laminar patter( laminar cortical necrosis)
145
list all causes of laminar cortical necrosis
* hypoxia
* thiamine deficiency in cats/ruminants
* salt poisoning in pigs
* lead poisoning in cattle
146
what are the lesions of CNS necrosis
softened to liquefied,yellow,greenish or brown color and fluorescent
147
discuss lesions of acute necrosis of CNS
* prominent hemorrhages
* softened, swollen gyri
* friable and irregular on cut surface
* bluish red or grayish
148
discuss subacute to chronic necrotic lesions of the CNS
* **yellow,greenish or brown color **
* liquefation
* large cavities fille with gelatininous, opaque yellowish or brownish fluid
* flattened gyri, glial scarring
* brain edema in surrounding tissue
149
what makes neonates less susceptible to hypoxia
1. lower cerebral metabolic activity
2. ability to utilise lactate
3. high content of ascorbate which may be protective
150
what potentiate reperfusion injury
1. oxygen radicals
2. ca influx
3. glutamate neurotranmitter
4. lactic acidosis
151
what is the sequela of hypoxia-ischemia
* swelling of perineunal astrocyte foot process
* neuronal contrascture
* cytoplasmic eosinophilia
* nuclear pyknosis
* karyolysis
* cell dissolution
152
list specific disorders of animals encompassed by CNS hypoxia-ischemia
* Neonatal maladjastment syndrome
* anesthesia related syndrome in horses
* hypoglycemia
* fibrocartilaginous embolic myelopathy
* feline ischemic encelopathy
153
what are the consequences of hemorrhages in brain or meningis
* acts as space occupying lesions causing increased ICP
* clots may cause blocks resulting in internal or extrrnal hydrocephalus
* organised thrombi and blood clots may bt epileptogenic
*
154
discuss localised edema
* it is caused by and surrounds space occupying lesions such as neoplasia, inflamation, focal necrosis,trauma and hemorrhages
* in most cases it is extensive and contributes more to the clinical signs than the primary lesions
* edmatous areas are swoolen and have soft ,depressed and moist appearance on cut surface.
* there is faint yellowish discoration on the edematous tissue
155
which edema reflects direct damage to osmoregulation
cytotoxic or intracellular edema
156
what are the histological lesions of cytotoxic/intracellular edema
nuclear and cytoplasmic swelling and accumulation of glycogen granules witin the cells
157
what are the gross lesions of cytotoxic/intracellular edema
brain swelling is characterised by swollen, tugid brain which is not moist on cut surface
158
vasogenic edema is prominent in which part of the CNS
white matter
intersttial
159
explain how vasogenic edema occurs
extracellular fluid accumulates due to vascular damage which allows the leakage of plasma and variable amounts of protein into the intersttial tissue
160
describe the appearance of recent and severe edema
* the brain is swollen,pale,soft and wet
* the hemispheres droop over the edges of cut bone of the cranium prior to the removal of the brain from the cranium
161
describe the appeareance of severe chronic edema
* the gyri are flattened, the sulci are shallow and signs of isappearance occur
* displacement of brain
162
discuss displacement of brain due to severe compression
* medulla omblongata and posterior portion of vermis herniate through the foramenmagnum.
* this lipping in may cause internal hydrocephalus
163
sequela of edema
* swelling,
* distortion
* ,herniation,
* brainsterm injury
164
what are the lesions of equine neonatal maladjustment syndrome
* schemic laminar cortical necrosis
* necrosis in the brain stem and multiple haemorrhages through the brain
165
what are the lesions of cerebrospinal angiopathy in pigs
* it is edema disease of pigs
* it is characterised by fibrinoid changes in arterioles in various areas of the body
166
what are the lesions of annual rye grass toxicity
lesions are sparse and consists mainly of edema
167
what are lesions of feline ischemic encephalopathy
cerebral infaction of the middle cerebral artery
168
list diseases that causes cerebrospinal vasculities
* sporadic bovine encephalomyelitis (SBE)
* malignant fever (MCF)
* lesions are aggrevated by subsequent fibrosis
169
what are consequences of CNS inflammation
* pronounced vascular response
* perivascular cuffing
* neuronal degeneration/death
* gliosis
* demyelination due to disease like distemper
170
infectious meningoencephalities is more common in which animals
cats
171
idiopathic inflamatory brain disorders are more common in which animals
dogs
172
give the 3 examples of idiopathic inflammatory brain disorders in dogs
1. granulomatous meningioencephalitis ⇒marked perivascular cuffing
2. necrotising encephalitis⇒multifocal,necrotic, cavitating lesions
3. generalised idiopathic tremors
173
what are the clinical sings of histophilus infection
its an acute infectous disease characterised by;
* fever, depression
* weakness
* ataxia
* blindness
* polyarthritis
* coma
* death
174
what are the gross lesions of histophilus somni
lesons are single or multiple hemorrhagic foci(infacts)located in any part of the brain
175
what are the microscopic lesions of histophilus somni
vasculitis with thrombosis and septic infaction in the brain as well as in other organs
176
what manifest listeriosis
1. encephalitis or meningoencephalitis in adult ruminants
2. septicemia with focal hepatic necrosis in young ruminants and monogastric animals
3. septicemia and myocardial degeneration or focal hepatic necrosis in fowl
4. abortion and prenatal infection may occur in all susceptible mammals
177
what are the gross lesions of listerial ewncephalitis
* usually not observed in the brain however,occassional grayish foci of malacia may be found in cross sections of the medulla
* listeria has affirnity for the brainsterm and lesions are more severe in the medulla and pons
* infection reach the brain though cranial nerves
178
what are the microscopic lesions of listeria
primary lesion is circumscribed collections of mononuclear cells with/out neutrophils in close proximity to blood vessels
179
discuss two morphologc patterns of enterotoxemia due to clo. perfuringins type D
1. the more common pattern is hemorrhagia and softening of the basal ganglia
2. the second pattern is characterised by lysis and liquefaction of the white matter of the frontal gyri which spares only the common 'U' fibers
180
discuss the pathogenesis of c.perforingins type D
epsilon toxin→vascular injury→increase vascular permability→edema→hypoxia-ischemia→necrosis
181
what feature is common in lambs with c.peforingins type D infection
glucosuria
182
discuss the pathogenesis of edema disease of swine
e.coli infection→toxin(shiga like) production→angiopathy→vasculitis→edema→hypoxia-ischemia→bilateral symmetrical foci of malacia/necrosis
183
discuss vascular reaction ue toviruses in CNS
* perivascular cuffing by lymphocytes, plasma cellsand macrophages
* thrombosis is rare
* large infiltratesm may cause compresson of vessels and ischemia
184
discuss neornal changes due to viral infection
* usually non specific
* neurological dearangement may be observed without any neuronal changes
185
discuss effects of viral infection on the white matter
1. mostly secondarily affected in viral disease
2. cuffing,microgliosis and demyelination may occur
3. demyelination is characteristic for certain disease e.g canine distemper
186
discuss meningitis due to viral infection
a lymphocytic meningitis may occur focally or diffuse
187
what are histological changes due to viral infection in the CNS
1. vascular reaction
2. neuronal changes
3. cuffing,demyelination and microgliosis in the white matter
4. meningitis
5. inclusion bodies
188
what are the gross lesions of cerebral nematodiasis
* hemorrhages,
* malacia
* migratory tracts
* or space occupying cysts
189
which larvae parasite of rabbits and rodents can invade the CNS of dogs and cats
cutebra spp
190
dicuss the pathogenesis of cutebral spp and resultant lesion in cats
* invade the CNS of cats and dogs
* abberant migration of the larvae
* vascular lesion--hemorrhages,vasculitis
* resulting in ischemic encephalopathy
191
which CNs parasite affets the young adult horse
sarcocystosis
causes equine protozoal encephalomyelitis{EPM}
192
discuss the pathogenesis of sarcocystosis
localization in the spinal cord \>focal parasitic activation and replication\>inflammation\>axonal damage\>axonal transection\>axonal swelling and degeneraton\>wallerian degeneration
193
cresent shaped parasite of the CNS
toxoplasmosis
194
what are CNS lesions of toxoplasmosis
* hemorrhages
* infacts
* edema
* non supperative inflammation
195
what are the lesions of neoporosis in dogs, horses and cattle
* dogs\>polyradiculoneuritis and polymyositis
* hoses\>meningoencephalomyelitis
* cattle\>multifocal necrosis
196
an oval or spherical thick walled yeast like bodies surrounded by a wide gelatinious capsule was removed was seen on a cut surface of tissue.the tissue tissue had mucinnous quality.which organism do you suspect
cryptococcus neoformans
197
which animals are naturally deficient in thiamine
cats
mink
fox
198
discuss the pathogenesis of thiamine deficiency
* thiamine required to maintain ATP pump
* thus in thiamine def.membrane repolarization is impaired
* water and eleectrolyte balance is impaired
* and thiamine pyrophosphate reduced
* pyruvate and lactate accumulate in the tissues causing necrosis
199
what causes polioencephalomalacia or CCN in ruminants
thiamine def.
200
what are the clinical signs of thiamine def. in ruminants
* incoordination
* recumbency
* bradycardia
201
what are the lesions of thimine deficiency in cats
* edema
* perivascular dilation
* hemorrhages and necrosis of brain tissue
*
202
what causes swayback in lambs
Cu def.
203
what are the gross lesions of swayback in lambs
bilateral cerebrolateral lesions
204
what are the clinical signs of Cu def. in lambs and kids
(swayback)
enzootic ataxia
205
what are the microscopic lesions of Cu def.
* astrogliosis associated with degeneration of white matter
* lesions of the brain sterm and spinal cord consists of chromatolysi, neuronal degeneration and necrosis of myelinated axons
206
lesions of vit E def. in chicks
1. encephalomalacia
2. exudative diathesis
3. nutritional muscular dystrophy
207
what causes metabolic encephalopathies
1. ionic imbalances
2. acid base imbalances
3. hypoglycemia
4. hypoxia
5. renal failure
6. hepatic encephalopathy
208
what are the gross lesions of yellow star thistle in horses
sharply demarcated foci of yellow discoloration and malacia
209
what are the microscopic lesions of yellow star thistle
* necrosis with loss of loss of axons,neurons,glia and blood vessels,
* influx of macrophages
210
what are the lesions of lead poisoning
* hemorrhages and edema
* also
* immunosuppressive
* irritating
* gametotoxic
* teratogenic
* nephrotoxic
* toxic to the hematopoitic system
211
a calf start to stagger ,develop muscular tremers and rapidly becomes recumbant.what should be high in your differential diagnosis
lead poisoning
212
an adult cowhas its head pressed on the tree and later becomes blind and dies from convulsions.what should be high in your differential list
lead poisoning
213
discuss the type of necrosis seen in subacute to chronic lead poisoning
laminar cortical necrosiswhich is associated with ischemia and anoxia
214
what causes acute paralytic syndrome(bilateral poliomyelomalacia) in pigs
se toxicity
215
what are the gross lesions of se toxicity
areas of softning and yellow discoloration in the ventral spinal gray matter of the cervical and lumbar intumescences
216
discuss the pathogenesis of organophosphate toxicity
* either inhibition of cholineserase
* or delayed neurotoxicity unrelatedto cholinesteraseinhibition
217
a cow is presented with hyperactivity(or depression), miosis,respiratory difficulty, mm tremors or fascuculations and salivation.what should be top of your rule out list
organophosphate toxicity
n.b there are no gross or micro. lesions in inhibition of cholinesterase mechanism
in the delayed neurotoxicity mechanism, there is dying back neuropathy
218
a pig is presented with blindness,deafness, headpressingand convulsions.the pig walks backwards and sit downwhat should be top of your rule out list
salt poisoning
219
what are the microscopic lesions of salt poisoning in pigs
eosinophilic meningoencephalities and encephalomalasia
220
a horse is presented with drowsiness,impaired vision,partial or complete pharyngeal paralysis,weakness, STAGGARING AND TENDENCY TO CIRCLE. what disease/condition do you suspect.
leukoencephalomalacia associated with moldy corn(MYCOTOXICOSIS)
221
DISCUSS THE PATHOGENESIS OF LEUKOENCEPHALOMALACIA
* TOXIN=FUMONISIN B1
* vascular damage\>infaction?]
* inhibit the enzyme ceramide synthase interfering with the synthesis of sphingolipids
* disruption of the cell membrane
* lipid peroxidation
* production of TNF alpha by macrophages
* inhibition of synthesis of DNA
222
what are the gross lesions of leukoencephalomalacia
* necrosis of the white matter of the cerebral hemisphere
* the malacic foci are pulpy,grayish depressions with small hemorrhages
223
what are the lesions of anoxia
it produces neuronal necrosis and softning of the gray matter
224
what are the lesions of equine wobbles
brownish yellow foci of malacia
225
discuss mechanisms of cholesteatosis of old horses
inflamatory changes\>cholesterol changes are found in this lesions
226
most common primary NS tumer of both dogs and cats
meningioma
they are often located in the olfactory bulb or frontal lobe
227
this tumer is well encapsulated and characterised by whorls and solid cords of spindle shaped cellsof uniform sizeand shape
meningioma
228
this tumer is seen most freguently in dogs espercially brachycephalic breeds
glial tumers
229
solid grayish,pooly encapsulated tumer
astrocytoma
* it is the most common of the glial tumers
230
what are the lesions of oligodentrioma
* soft cyst like
* it is well demarcated ,being grayish and soft
* microscopically it is densly cellular with almost no stroma
231
* this tumer is uncommon in animals but well known in childrean
* it is composed of of cells of unknown %
medulloblastoma
232
well confined,soft grayish or pinkish masses unilaterally in cerebellar cortex or central in the vermis extending or compressing the 4th ventricle
medulloblastoma
it consists of masses of black staining cells that are round,enlongated or pyriform with oval or enlongated nuclei
233
what are the characteristics of ependymoma
* they are largeintraventricular masses,well demarcated,gray and freshy
* intratumural cystic area
* necrosis and hemorrhages may be present
* **can cause hydrocephalus**
234
this condition is characterised by abnormally flattened and narrowed frontal part of the cranium.and the frontal bones are thicker than normal
microencephaly
235
what causes microencephaly
associated with fetal infection by akabane virus in lambs,bvd virusin calves,border virus in lambs
