Neuropathology 3 Flashcards
Non-infectious /immune mediated
Granulomatous meningoencephalitis
Necrotizing encephalitis
Necrotizing leukoencephalitis
Granulomatous meningoencephalitis
GME
Angiocentric gran inflammation
Can lead to necrosis & loss of neuropil, asymmetrical
Necrotizing encephalitis
NME
Pug dog encephalitis, affects many small breed dogs
Asymmetrical acute encephalitis or chronic foci of necrosis & collapse
Necrotizing leukoencephalitis (NLE)
Most common in Yorkshire terriers
Lesions primarily in white matter
Traumatic injury = primary
Sheer force causes destruction of neurons /other cell types
Mechanical disruption of vessels leads to local hemorrhage & edema
Traumatic injury = secondary
Disruption of cerebral blood flow leads to catecholamine release
^^ BP = global edema, follows resulting in necrosis /more edema
If edema is expensive, cerebellum can herniate through foramen magnum
Coning of the cerebellum
Caudal herniation of brain
Traumatic spinal cord injury - intramedullary comp
Hemorrhage
Neoplasia
Expansile inflammatory disease
Traumatic spinal cord injury - extramedullary comp
Intervertebral disc herniation
Cervical stenotic myelopathy
Atlanto-axial malformation
Vertebral fractures
Extramedullary neoplasia
Synovial cysts
Cervical stenotic myelopathy
“Wobbler syndrome”
Stenosis of cervical vertebral canal
Horses & large dog breeds
Static stenosis in 1-4 old due at acquired narrowing of canal (compression occurs C5-7)
Dynamic stenosis <18 months due to vertebral instability (compression occurs during flexion of neck, C3-5)
Intervertebral disc disease
Complex multi factorial disease - in dogs, discs rupture in thoracolumbar vertebrae
Herniation results in spinal cord compression and rear limb paralysis
Chondroid metaplasia
- chondrodystrophic breeds (dach/pekingese)
Fibroid metaplasia
Non-chondrodystrophic breeds
Type I herniation
Acute
Chondroid degeneration —> rupture of annulus fibrosus -> extrusion of nucleus palposus
Type II herniation
Chronic
Fibroid metaplasia of IVD -> protrusion into spinal canal
Neoplastic
50% of brain tumor are primary (originate from neural tissue)
2-5% of all cancers in the dog = primary intracranial neoplasia
All tumors behave as space -occupying masses
Anatomic location may help in diagnosis
Demarcation for neoplastic tumors- gliomas
Gliomas - astrocytomas & oligodendrogliomas tend to blend in with adjacent tissue, oilgo have gelatinous consistency
Demarcation of choroid plexus
Choroid plexus tumors & ependymomas are located in/adjacent to ventricle - choroid plexus tumors are more vascular
Demarcation of meningiomas
Meningiomas line the meninges
Astrocytoma
Neoplastic cells of origin are astrocytes
Choroid plexus tumors
Arise from choroid plexus
(Responsible for producing CSF)
Meningioma
Cell of origin - Meningeal fibroblast
Ependymoma
Arise from ependymal cells that line the ventricles
Spinal cord neoplasms
Peripheral nerve sheath tumor - benign & malignant forms
Nephroblastomas
“Thoracolumbar spinal cord tumor of dogs”
Ectopic, located between T9 & L3
Large breed dogs
Usually 5-48months
Degenerative
Bilateral, symmetrical but no gross lesions
Many breed specific diseases
Diagnosis is based on the nature & distribution of the lesions, knowledge of breed disorders, exclusion of metabolic/toxic diseases
Major patterns of degeneration
Loss on neurons/axons/myelin
Pallor of white matter
Spongy state
Intracellular storage
Malacia
Lysosomal storage diseases
Congenital defect
Loss of lysosomal hydrolase enzyme activity
Molecules that cannot be degraded accumulate in the lysosomes
Storage diseases are named based on the accumulated products /locations
Degenerative myelopathy
