neuropathology 2 Flashcards
CNS disease categories
- Malformations
- Encephalitis / Inflammatory
- Encephalopathy / noninflammatory
- Neoplastic
Malformation of the CNS
- general reasons for this
- Spontaneous
- Hereditary
- Toxic
- Post infectious
Malformations of CNS - common ones
- Hydrocephalus
- Hydranencephaly
- Cerebellar hypoplasia
Hydrocephalus - what is this? types?
- Water brain > Bone forms to brain
- Ventricles dilated
- Internal - common
- External - rare
Hydranencephaly - what is this?
- what is the mild form?
- water, but no brain
- cerebrum doesnt develop
<><><><><>
Mild hydranencephaly = porencephaly
> holes in the brain, because some parts formed, but others did not
Cerebellar hypoplasia - what animal and disease is this related to most?
Feline panleukopenia virus
<><><><><><>
> can also see this in calves (BVDV)
Neurotropic viruses that cause malformations
- Family Flaviviridae; Genus Pestivirus;
> Pestivirus bovis, P. tauri (BVDV1 and BVDV2),
> Pestivirus suis (Classical Swine Fever V),
> Pestivirus ovis (Border Disease virus) - Family Parvoviridae; Genus Protoparvovirus; Species Protoparvovirus carnivoran1:
Feline panleukopenia virus - Family Reoviridae; Genus Orbivirus; Bluetongue virus
- Family Peribunyaviridae; Genus Orthobunyavirus;
> Orthobunyavirus akabaneense (Akabane virus),
> Orthobunyavirus cacheense (Cache Valley virus),
> Orthobunyavirus schmallenbergense (Schmallenburg virus)
Encephalitis \ Inflammation
> infectious causes / types
- Neutrophilic (Bacteria)
- Lymphocytic (viral)
- Eosinophilic (Parasitic)
- Granulomatous
- Necrotic/ Myelinopathy/ Malacic
Cells of the Central Nervous System
- Neuron > Nerve cell body, axon and dendrites
- Microglia and macrophages > Myelin macrophages
- ‘Macroglia’
> Astrocytes (multifunctional)
> Oligodendrocytes (myelin production)
> Neurolemmocytes (Schwann cells) too - Stem cells – neuroblasts, aldynoglia
Route of entry of pathogens to CNS
- Exposure – primary replication – blood – tropism for CNS
- Veins (cornual – ophthalmic – cavernous sinus)
- Direct penetration > dehorning
- Along nerves > Herpesviridae, Lyssavirus, Listeria
- Through CSF > Spinal abscess
Central Nervous System: Inflammation
1: Neutrophilic inflammation - bacterial
- mostly what? pathogens?
- lesions?
- exceptions?
- Mostly Meningitis
> Ruminants
=> E. coli
=> Streptococci
><><><><><>< - Abscess
> Brain
> Trueperella pyogenes
><><><><><><><
– exceptions: - pituitary abscess
- Listeria monocytogenes
> Cattle, sheep and goats
> Mouth
> Trigeminal nerve (V) and ganglia
> Microabscesses in pons and medulla - Histophilus somni
> Gram -, necrosis to small vessels and
neutrophils, thrombosis, microinfacts =
malacia
- Lymphocytic (viral) encephalitis
- lesions
- ‘nonsuppurative’ encephalitis
- Perivascular cuffs
- Gliosis > Focal, Diffuse
- Neuronal lesions > Necrosis, Satellitosis, Neuronophagia
- Viral diseases of CNS, for all species:
All species:
- arboviruses
<><>
- Family Rhabdoviridae
> Genus Lyssavirus – Rabies lyssavirus
<><>
- Family Herpesviridae
> Genus Varicellovirus - BoHV, CaHV, FeHV
<><>
- Family Paramyxoviridae
> Genus Morbillivirus – Canine morbillivirus (Distemper)
> Genus Henipavirus – Nipah henipavirus, Hendra henipavirus
<><>
- Family Astroviridae
> Genus Mamastrovirus - BoAstV, PoAstV, OvAstV
viral diseases of CNS in horses
- Family Togaviridae; Genus Alphavirus
> Eastern equine encephalitis virus,
> Western equine encephalitis virus
> Venezuelan equine encephalitis virus
<><>
Family Flaviviridae; Genus Flavivirus - West Nile Virus
Viral encephalitis - RABIES - signs in horses, cattle, dogs
- Lyssavirus rabies: Rabies virus
<><>
Horses - ‘lameness’, ataxia
Cattle - paralysis
Dogs - aberrant
where does rabies like to be in the brain?
Hippocampus and cerebellum
classical histological signs of rabies
Rabies virus inclusion (Negri) bodies
Pathogenesis of rabies
Bite
Muscle
Peripheral nerve
CNS
Nerves
Salivary glands
An exception to lymphocytic viral
disease….
in Cats
- Feline infectious peritonitis
> Alphacoronavirus 1 - Feline infectious peritonitis
virus (FCoV)
> Suppurative and pyogranulomatous
Inflammatory disease with malacia
/demyelination
- in cattle
Thrombotic Meningoencephalitis (TME)
> Histophilus somni
> Septic thrombi, malacia
Inflammatory disease with malacia
/demyelination
- in horses
- Equine herpesviral encephalomyelopathy (Varicellovirus equidalpha1 – neuropathic form)
> Vasculopathy with endotheliotrophism/ direct injury or Type III Arthus Reaction immune vasculitis - infarction
Inflammatory disease with malacia /demyelination
- in dogs
- Morbillivirus canis (Canine distemper virus)
> demyelination
Non-infectious Encephalitis \ Inflammation looks like:
Non-infectious inflammation is similar in character to the infectious causes, and considered immune mediated.
- perivascualr cuffing
- local gliosis
- regions of infarction
- can be neutrophilic, lymphocytic, eosinophilic, granulomatous, necrotic/myelinopathy/malacic
- all considered immune mediated in these cases!
