CNS 4, 5 and Practical Flashcards
What parts of the CNS are mainly affected by corticocerebral necrosis?
How are acute and chronic lesions characterised?
What are the suspected causative agents?
Mainly affects the cerebral cortex
Acute lesions are characterized by oedema and red hypoxic neurons affecting specific laminae of the cerebral cortex- swollen brain
Chronic lesions are characterized by cavitation of the affected cortex, gitter cell proliferation, glial scar formation
Sulfur intoxication and thiamine deficiency are suspected, causative agents
What agent causes focal symmetrical encephalomalacia in ruminants?
Describe the pathogenesis
What happened in chronic lesions?
Clostridium type D in ruminants- e toxin
Pathogenesis-
Alterations in the intestinal environment cause inadequate flora and undigested starch passes into the intestine and promotes C. perfringens growth low glucose stimulates epsilon exotoxin production
passes through intestinal mucosa causes endothelial damage and increased vascular permeability
causes vasogenic brain oedema and hypoxic-ischaemic necrosis
Chronic lesions- severe symmetrical encepholomalacia
What causes swayback?
What causes it?
What are the symptoms?
How does is grossly appear in the CNS?
Congenital copper deficiency in lambs
Copper-deficient or molybdenum-rich diets during gestation
Neurological symptoms at birth-
animals are blind and ataxic, immobility, death
Grossly- ventricular distension due to bilateral symmetrical rarefaction of the periventricular grey matter
What can moderate/chronic porto-systemic shunts or severe or acute hepatic dysfunctions provoke?
Describe the pathogenesis?
Can provoke toxic encephalopathy
Pathogenesis- the detoxifying role of astrocytes is overwhelmed by increased haematic concentration which is metabolised to glutamine leading to cytotoxic oedema
Severe spongy state of the white matter and Alzheimer’s type II cells
What are the different developmental abnormalities of the CNS?
- Neural tube closure defects
- Defects of forebrain induction
- Neuronal migration disorders and sulcation defects
- Encephaloclastic defects
- Malformation of the caudal fossa
- Abnormality of the CSF
What is spina bifidia (SP)?
What are the different forms?
Failure of the development of the vertebral arch of the spine (lumbar)
SP occulta- skin covering is incomplete
SP aperta- spinal defect is visible through open skin
Meningocele- fluid-filled hernial sac composed of arachnoid dura mater
Meningomyelocele- fluid-filled hernial sac composed of trophies neroparenchyma
What does hydrocephalus mean?
What is communicating hydrocephalus?
What can cause it?
Hydrocephalus- increase in volume of CSF
Communicating hydrocephalus- bilateral and symmetrical dilation without detectable lesions
Acquired, congenital or obstructive (parasites, viruses)
What do the following terms mean?:
Hydromyelia
Syringomyelia
Syringobulbua
Hydromyelia- fluid-filled cavity within the spinal cord, lined by a continuous layer of ependyma
Syringomyelia- fluid-filled cavity within the spinal cord following rupture of the ependymal covering
Syringobulbia- similar lesion involving the brain stem
What kind of tumour is this?
Where do they commonly arise?
How does the cut surface commonly appear?
What increases the chance of malignancy?
Astrocytoma- tumour of astrocytes
Generally arie supratentorially (cerebral hemispheres, white matter)
On cut surface appear firmer than normal parenchyma, whitish and poorly un-demarcated
Increasing malignancy- cell atypia, infiltrative -> neogenesis to necrosis
Graded I to IV
What is an oligodenroglioma?
What species does is affect?
Where is it frequently located?
What tendencies does it have?
How does it grossly and histologically appear?
Oligodendrocytes tumour- produced myelin
Occurs in dogs, cattle, cat and horse
Frequently in frontal, temporal and parietal cortex
Strong tendency to induce a pronounced neoagniogenesis and intratumoural haemorrhages
Grossly- well circumscribed, sharply demarcated, gelatinous
Areas of necrosis, haemorrhage, cystic degeneration and are associated with increased malignancy
Histo- honeycomb appearance, small nuclei surrounded by empty halo
What does an meningoma arrise from?
Where is it more commonly located?
How does it grossly appear?
How can it present in cats?
Very common in dogs and cats
Arising from the meninged covering the CNS
Preferentially located in the anterior fossa, more commonly over the cerebral convexities
Grossly- lobulated, often granular, white to tan with a broad based attachment to the meninged
In cats- can be multiple and expand causing compression of the CNS
Most commonly transitional
Where are choroid plexus carcinomas/pappilomas likely to arrise?
How do they appear grossly?
Where does an ependymoma arise from?
What condition are they commonly associated with?
How do they appear grossly and histologically?
Airise from epithelium of choroid plexus, mainly in 4th ventricle
Grossly- large, granular and rough texture
In carcinomas- haemorrhage, necrosis, infiltration
Ependymoma- arising from ependyma lining the ventricles
Frequently associated with obstructive hydrocephalus
Grossly- large, well demarcated, tan solid intraventricular mass
Histo- pseudorosettes and GFAP variably positive
metastsis can occur by CSF
What is the difference between these two neoplasms?
Top right- haemangiosarcoma (right ventricle, spleen)
Bottom left- melanoma
What is axonal degeneration?
How does it appear histologically?
What does the description wallerian like mean and what does it lead to?
Segmental degeneration of axons and myelin caudally to the site of an insult
Histo-
- Formation of multiple spherical enlargments containing swollen axons
- Leads to disintegration of myelin leading to necrosis leading to macrophages
- Leads to proliferation of schwann cells in repair attempt- axonal sprouting
Wallerian like- degeneration that is not due to focal trauma
Consequent lack of conduction- deneravation atrophy of the effector organ, anterograde and retrograde transynaptic neuronal degeneration
What causes vascular disease of the PNS - ileo-aortic thromboembolism
What is it associated with?
How does it clincally appear?
Thrombosis of distal abdominal aorta and the junction with internal and external iliac arteries leads to acute ishemic infarction of the peroneal and tibial nerves and muscles
Associated with vulvular endocarditis and asymmetrical cyanonosis of plantar surface
Clinical- sudden paraparesis or paraplegia with painful hard muscle and lacking of femoral pulse- common in cats
This image shows the histology from a brainstem lesion in a 3yo freisian cow with progressive dysfunction in motility of the tongue
What are the following letters?:
M
H
N
B
What is the MD?
M- necrotic neuron
H- Microabscesses
N- Odedma of the myelin axon
B- spongiosis
MD- bovine brainstem- focal, severe and subacute supprative and lymphoplasmacytic encephalitis with spongiosis and neuronal necrosis
GSD with rapid progression of neurological signs, where is the lesion?
What is the lesion highlighted on this image mainly affecting?
Optic tract
What type of matter is affected in this image?
What is E, B and G?
E- perivascular cuff
B- spongiosis
G- Engorged blood vessel- hyperaemia
What are the letters showing?
H
M
J
H- oedema wuthin the myelin axonal fragmentation
M- perivascular cuff
J- geminstocytic astrocyte
What is
E
B
I
E- perivascular cuff
B- Severe spongiosis
I- Meningeal hyperaemia
What are the arrows pointing to in this image?
Intranuclear inclusion bodies
Wheres it the lesion located?
What kind of mass is it?
How is it characterised?
Brain stem
Focal mass
Caviation- intense rarefraction of the parenchyma (reduction in density)
What are the boxes showing?
E
I
F
E- parencymal cavitation
F- perivascular cuff
I- Gliosis
Glia- are the non-neuronal cells in the CNS (oligodendrocytes, astrocytes, ependymal cells, microglial cells)
What does this image show and what is it?
Gitter cells-
enlaerged phagocytic cell of microglial cell origins having the cytoplasm distended with lipid granules
What does the box show?
Gemistocytic astrocyte
