Lecture 4: Neuropathology: inherited, congenital, and degenerative diseases Flashcards
What are some potential causes of congenital malformations
- Viruses
- Toxins
What are some viruses that cause congenital malformations
- Orthobunya viruses
- Orbiviruses- bluetongue
- Pestiviruses- BVD, border disease
- Parvoviruses
Parvoviruses cause ___malformations
Cerebellar
What is anencephaly
Brain largely absent at birth
What happens to fetus of sheep infected with blue tongue at 50 days
Severe hydrancephaly
What happens to fetus of sheep infected with blue tongue at 75 days
Scattered proencephalic cysts
What happens to fetus of sheep infected with bluetongue at 100 days
No gross lesions
What this and potential cause
hydrancephaly
Cause: blue tongue virus
What happens in hydrancephaly
Cerebrum and cerebellum are replaced by thin-walled, fluid filled cysts
Only brainstem preserved
What causes this
Ingestion of Veratrum californium by pregnant eyes during 14th day of gestation
What is the most common mechanism of hydrocephalus
Obstructive- fluid accumulates in front of obstruction or resorbed back into venous circulation
What is the most common site of obstructive hydrocephalus and due to what
Stenosis or inflammation leading to obstructive hydrocephalus at mesencephalic aqueduct
What wrong
Left: bilateral hydrocephalus
Right: asymmetrical hydrocephalus
Who is affected with congenital hydrocephalus
Toy breed dogs (chihuahuas)
What causes the congenital hydrocephalus
Fusion of rostral colliculi resulting in obstruction of aqueduct
What are the consequences of hydrocephalus
Dilation of ventricles from increased CSF pressure and gradually causes compression atrophy off surrounding neural parenchyma
Describe these lesions and what caused them
Ventricular dilation before skull bones ossify leading to enlargement of cranium with open fontanelles
Cause: hydrocephalus
What is porencephaly
Fluid filled cystic spaces that may or may not communicate with the ventricular system
Identify which one is hydrocephalus vs porencephaly
Left: hydrocephalus
Right: porencephaly
What is a meningocele
Defect in calvarium that allows outpocuhing of meninges
Brain unaffected
What is a meningoencephalocele
Ddefect in calvarium that allows out poaching of both brain and meninges
What this
meningocele
What is lissencephaly
Failure of gyro and Sulli to develop resulting in smooth cerebral surface
What causes lissencephaly
Arrest of normal migration of neurons during development
What species is lissencephaly normal in
Rodents, birds, reptiles and some primates
What this
lissencephaly
What are some clinical signs of cerebellar malformations
Base-wide stance, spastic hypermetric gait, loss of balance/ataxia
What is the timing for cerebellar malformations
Most active period of proliferation of external germinal layer of the cerebellum is shortly after birth through 2 weeks postnatal
What is the most common cause of cerebellar malformations
Viral induced necrosis of external granular cell layer—> cells do not migrate to internal granular cell layer- cerebellar hypoplasia
What viral families are typically involved in cerebellar malformations
- Parvoviruses- canine parvovirus and feline panluekopenia virus
- Pestiviruses- border virus and BVD
What wrong
cerebellar hypoplasia
What is neuronal abiotrophy
Premature accelerated degeneration of fully formed neurons
What is the best described neuronal abiotrophy
Cerebellar cortical abiotropgy
What are some clinical signs of cerebellar cortical abiotrophy
Cerebellar ataxia, head tremor, symmetric hypermetria, spasticity, broad-based stance, loss of balance
What is the age of onset of cerebellar cortical abiotrophy
Normal at birth, clinical signs show up around 4-16 weeks
What are the microscopic lesions associated with cerebellar abiotrophy
Marked Purkinje cell necrosis, dengeration and loss
Which normal vs abnormal and what is wrong
Left: Normal
Right: cerebellar abiotrophy- loss of Purkinje cells
What horse breed is predisposed to cerebellar abiotrophy
Arabians
What is dysraphism
Developmental anomaly involving failure of fusion of the neural tube
What is the most common form of dysraphism
Spina bifida
What is spina bifida
Fusion defect limited to the spine, most commonly lumbo-sacral region
What is the mild form of spina bifida
Small opening in the vertebral column—spina bifida occulta
What is the intermediate form of spina bifida
Meninges go out opening—meningocele
What is the severe form of spina bifida
Meninges and spinal cord go out- myelomenigocele
What wrong
spina bifida
What cat breed has high incidence of spina bifida
Manx cats
What is syringomyelia
Results in development of fluid containing cavities within the parenchyma of spinal cord as a consequence of abnormal CSF movement through foramen magnum
What does this show
syringomyelia
What wrong
syringomyelia
The pathogenesis of syringomyelia involves ___
Occipital dysplasia
What is occipital dysplasia also called
Chiari-like malformation
How does occipital dysplasia cause syringomyelia
Cerebellum at foramen magnum results in crowding and creates turbulent flow in CSF which can result in accumulation of free fluid within the spinal cord
What’s wrong and what is the result
chiari-like malformation/ occipital dysplasia
Can cause syringomyelia
What breed is poster child for syringomyelia
KCCS
___% of KCCS have chiari-like malformation and ___% of ___as a result
95-99%, 70% have syringomyelia
What are some clinical signs of syringomyelia
Phantom scratching, cervical pain, rubbing face, neck and ears
What is demyelination
Loss of normal myelin around axons
What is dysmyelination
Formation of abnormal myelin during development
What is hypomyelination
Partial or complete lack of myelin development
Dysmyelination and hypomyelination are known as ___
Leukodystrophies
What are the microscopic lesions associated with degenerative myelopathy
White matter degeneration in caudal thoracic and lumbar spinal cord- demyelination
What breeds commonly get degenerative myelopathy
GSD and corgis
What are some clinical signs of degenerative myelopathy
Progressive ataxia and paresis and ultimately paralysis of pelvic limbs
What this and what caused
Meningeal fibrosis- opacity most apparent over Sulci
Age related lesion
What is dural osseous metaplasia
Islands of mature bone within the meninges of spinal cord and sometimes bone marrow
What breeds likely get dural osseous metplasia
Large breeds- GSD
T or F: dural osseous metaplasia is an incidental finding that typically doesn’t;’t cause clinical signs
True
What wrong and what caused
dural osseous metaplasia
Age related lesion
What is equine choroid plexus cholesterol granuloma and where is it
aggregates of cholesterol typically found in ventricles and meninges
Horse: What this and what cause
Equine choroid plexus cholesterol granuloma
Age related lesion
T or F: equine choroid plexus cholesterol granuloma is a neoplasm
False
Equine choroid plexus cholesterol granuloma are typically incidental but when large can cause ___
Depression due to compression/ atrophy
