Neuro Flashcards
This kind of necrosis you will see cell swelling and central dissolution of Nissl substances leading to pale areas in the cytoplasm
Chromatolysis
Degeneration of axon and myelin sheath distal to the trauma or toxic injury
Wallerian Degeneration
Accumulation of glial cells-mainly microglia, around damaged neurons
Satellitosis
Phagocytosis of necrotic neurons
Neuronophagia
Accumulation of leukocytes
Perivascular cuffing
Which cell is responsible for myelination of axons within the CNS?
Oligodendroglia
Which cells are responsible for movement of CSF through the ventricular system
Ependyma
Which cells secrete CSF and is apart of the Blood-CSF barrier
Choroid Plexus epithelial cells
Which cells are apart of the immunosurveillance, immunoregulation, and phagocytosis
Microglia
Whats another name for the dura mater
pachymeninges
What structures are in the leptomeninges
Arachnoid and Pia mater
Name the meninge layers outside to in
Dura
Arachnoid
Subarachnoid
Pia
What canine virus can cause demyelination?
Distemper
What is softening and liquefaction of nervous tissue from necrosis of neurons and glial cells?
Malacia
What is it called when a microglial cell swells up, the cytoplasm has a lot of lipids in it and is foamy and enlarged
Gitter cells
Eosinophilic with internal granules with stain purple with methylene blue and basic fuchsin.
Negri bodies
What are the different types of congenital anomalies?
Neural Tube Closure Defects
Neuronal Migration Disorders
Encephaloclastic
Malformations of Cerebellum
Malformations of the spinal cord
Hydrocephalus
Whats it called when there is a total absence of the entire brain, but in reality what is true about this
Anencephaly
This term is used even though a small portion of the brain persists
often the medulla is present and occasionally some of the mesencephalon
Dysraphia is?
Neural tube closure defects
What is the failure of bilateral separation of the primitive single telencephal hemispheres?
Who is this common in and what are the lesions
Prosencephalic hypoplasia
Pigs and Lambs
has a SINGLE central ventricle
What is a protrusion of the brain + meninges through a defect in the cranium
Meningoencephalocele and cranium bifidum.
What is a protrusion of just the meninges
meningocele
What is a protrusion of the spinal cord + meninges
meningomyelocele
aka: encephalocele, cephalocele, craniocele
What if you have a dorsal defect in closure of one or several vertebral arches in a brachycephalics or manx cats?
Sacrococcygeal agenesis
What refer to the defect in the spine in an meningoenceophalocele?
Spina bifida
What happens during a congenital hydromyelia?
What can cause it
Abnormal dilation of central canal of spinal cord
can be infectious or genetic—causes damage to the ependymal cells
Simple dilatation of the central canal of the spinal cord causing excessive CSF is called
Hydromyelia
What happens during an aquired hydromyelia and what can cause it
Obstructions of the central canal CSF flow. from infection, inflammation or neoplasia
What is it called when the convolutions of the brain are almost entirely absent?
Lissencephaly (agyria)
What happens in lissencephaly? which dog breed does it occur in?
Absence of PRIMARY gyri, and an excessively thin cerebral cortex (dec # of neurons)
Lhasa Apso
Whats a destruction lesion of the brain called?
How about the focal vs diffuse kinds
Enceophaloclastic defects
Focal: Porenceophaly
Diffuse: Hydranenceophaly
Cysts in the wall of the cerebral hemisphere and can communicate w/the subarachnoid space or lateral ventricle? Where does it occur, white/grey matter? Is this focal/diffuse?
Porencephaly
WHITE matter
Focal lesions
lesions: complete/incomplete absence of the cerebral hemispheres, the leptomeninges form sacs enclosing CSF, large cystic spaces or savs in the cerebral hemisperes and the ependyma is absent
Hydranencephaly
Lesions: Decrease in size of cerebellum Loss of purkinge cells******* Narrow granular layer Normal molecular layer
Cerebellar hypoplasia
What is it called when there is a tubular cavitation of the spinal cord that extends over several segments, usually in the lumbar region. It is not lined with ependymal cells. What do the effected dogs looks like?
Syringomyelia
Affected dogs are unable to completely extend the hindimbs, and they may have a symmetrical hopping gait
What viral infections can cause cerebellar hypoplasia?
Feline Panleukopenia
BVD
Herpesvirus in dogs
Where are the cysts found in syringomyelia? Grey/White?
Grey matter
What are the two kinds of hydrocephalus?
Congenital
Acquired
What is an abnormal accumulation of fluid in the ventricles of the brain and sub-meninges
Hydrocephalus
What are the 3 types of hyrocephalus?
Internal: in the ventricles
External: in the sub-arachnoid space
Communicating: in both localities
What are the 3 possible pathogenesis of hydrocephalus?
Inc production of CSF
Obstruction of the normal flow of CSF
Defective absorption of CSF
Lesion: Dilated ventricles or the duct system. Dome-shaped, thin boned and enlarged cranium
Congenital hydrocephalus
What type of hydrocephalus is the acquired kind?
commonly internal
Lesion: Obstruction of CSF flow causing: Pressure atrophy of white matter and cerebral cortex, no malformation of the cranium**
what are the causes
Acquired hydrocephalus
Caused by:
Inflammation, cholesteatoma, neoplasia, parasitic cysts
What are the degeneration dz
Degen of neurons and axons Myelin disorders Storage dz Spongiform encephalopathies Spongy degeneration
Motor neuron Dz
Kind of self explanatory-degen and loss of motor neurons in the ventral horns of the spinal cord
Marked accumulation of neurofilaments caused by posttranslational protein modification and impairment of neurofilament protein transport.
Premature programmed cell loss that is a primary premature neuronal degen.
What two kinds can you get
Abiotrophy**
a type of apoptosis-but its premature
Restricted to the Cerebellar Cortex
or
Involve connected neural systems
What are the lesions for Cerebellar abiotrophy
Cerebellum is normal or shrunken
Loss of Purkinje cells** and granule cells. Seen in basal ganglia
How can you tell if its cerebellar abiotrophy or cerebellar hypoplasia
hypoplasia develops AFTER the cerebellum has attained its full complement and arrangement of neurons.
What is GCL deficient in?
the catabolic enzyme
GALC-galactosylceramide-B-galactosidase
When do you see the clinical signs of GCL?
2-7 mo of life
Where and what are the lesions for GCL?
WHITE matter degen-becomes grey and soft.
GALC accumulates, the macs become globoid which are neurotoxic which leads to CNS signs.
What happens in lysosomal storage dz?
The hydrolytic enzyme is absent or inoperational-so substrates will accumulate within the lysosomes. this is cytotoxic—necrosis of neurons, glial cells.
inherited
Are Prion Dz inflammatory?
NO
What dz has Cytoplasmic Vacuoles and Astrocytosis?*** What are the other lesions?
TSE’s-Prion dz
Accum of abnorm prion proteins.
Chronic wasting
How do you Dx Prion dz/TSE?
You need to look for the abnormal proteins + lesions in the OBEX of the BRAINSTEM*****
Or IHC in the lymphoid tissue of the third eyelid in live sheep with scrapie
Multiple fluid filled clear spaces in the WHITE matter due to accumulation of eduma fluid secondarily to: edema, wallerian degen, etc.?
Status Spongiosus
What are your 2 types of status spongiosus?
Aminacidopathies: maple syrup dz, bovine citrullinemia
Metabolic Encephalopathies: Hepatic and renal enceph.
Lesions: Malacia, maybe hemorrhage, selective necrosis/loss of neurons, axons, myelin. spongy state
Necrosis/malacia
Necrosis of grey matter
Necrosis of white matter
Poliomalacia
Leukomalacia
Necrosis of whole brain
Necrosis of spinal cord
Necrosis of brain AND spinal cord
encephalomalacia
Myelomalacia
Encephalomyelomalacia
What are ALL of the causes of Necrosis
Vascular: thrombosis, embolism, vasculitis, ruptured aneurysm
Cerebral hypoxia
Toxins: yellow star thistle, metals and salts, mycotoxins
Infections: theileriosis, moldy corn, clostridium perfringens, babesiosis, toxo
Nutritional: Vitamins: A,B,E
Minerals-copper
What kind of pattern will you see in a diffuse necrosis
laminar-due to selective susceptibility of various cells in the CNS to hypoxia
What kind of necrosis and what spp does Yellow Star Thistle Toxicity cause
Equine nigropallidal encephalomalacia
Clostridium perfringens type D causes?
Focal Symmetrical encephalomalacia in sheep
What are some things that will cause a laminar pattern necrosis
Thiamine depletion-ALL cats. CCN
Salt poisoning-pigs–Polio
Lead poisoning-cattle–Bilat. Polio
High Dietary sulfur-cattle–CCN/Polio
Which cells are susceptible to hypoxia and there for laminar cortical necrosis?
NOAM
Neurons (not all, in the 2nd and 3rd layers of cerebral cortex)
Oligodendrocytes
Astrocytes
Microglia
Look at the Necrosis slide with all the etiologies and distributions
seriously….DO IT
he told us to star star star star!!!!
What are the sequelae of necrosis
Gitter Cells**
Acute Hemorrhage** and softening–chronic liquefaction**
Congestion is Increased _____ blood flow and its what kind active/passive?
Venous
passive
Hyperemia is Increased _____ blood flow and its what kind active/passive?
Arterial
Active
==Hypoxia + hypoglycemia
Ischemia
Which cells are Sensitive to hypoxia-ischemia?
NOAMF
Neurons
Oligodendrocytes
Astrocytes
Microglia
Fibrovascular elements
What are the mechanisms of hypoxia-ischemia?
Lactic acidosis
calcium influx
oxygen free radicals
excitotoxins
What are the responses to hypoxia-ischemia
Swelling of perineuronal astrocyte foot processes
Neuronal contracture
cytoplasmic eosinophilia
nuclear pyknosis
karyorrhexis
karyolysis
Can anesthesia cause hypoxia-ischemia?
YES! post anesth hemorrhagic myelopathy
post anesth cerebral necrosis.
When your inhalant gases are devoid of O2
more than 5 min of hypoxia is lethal to neurons-intense cytoplasmic eosinophilia, pyknosis, karyolysis, liquefaction, macrophage reaction
What is a big reason for necrosis?
Hypoglycemia!!!!!
What are some reasons that can cause hypoglycemia leading to necrosis
fasting
addisons dz
hepatic & renal dz
glycogen storage dz
pancreatic B cell tumors
Tell me the pathogenesis of Fibrocartilaginous embolic myelopathy and what spp is this in?
Dogs
Degen of intervertebral discs–prolapse–hemorrhage, embolism, infarction–myelomalacia
What is a big cause of hypoxia-ischemia in cats? whats the pathogenesis
Feline ischemic encephalopathy
Migrating parasite–hemorrhage–vasospasm–cerebral ischemia
What is necrosis of tissue after obstruction of its arterial blood supply
Infarction
What are some etiologies of infarction
Tumor emboli
Compressive injuries to the CNS producing a sudden reduction in blood flow
Gradual reduction of blood flow through an artery
Anastomoses of the arteries that penetrate from the ventral and cortical surfaces of the brain, are insufficient to prevent infarction after sudden occlusion of one more of these arteries
What are some causes of hemorrhage
traumatic
spontaneous
What are some etiopathogenesis of hemorrhage
integrity of blood vessels-vasculitiis from pathogens/trauma, immune complexes, contusions
Coagulability of the blood
What is hematomyelia
hemorrhage of the central canal of the spinal cord
What are some consequences of hemorrhage?
no effect or…
SOL
blood clots
organized thrombi and blood clots
What accompanies all intracerebral lesions? and what are some consequences
Cerebral edema*****
inc intracerebral pressure—life threatening
Localized edema causes
SOL
Vague outline
if chronic-faint yellow discoloration
Generalized edema?
Diffuse inflammation
Toxemias and Intoxications
Cattle and Sheep==CCN
Vasogenic edema causes…and the outcome is….
Breakdown of the BBB
causes EC accumulation of fluid leaking into the interstitium, so its going to be moist and oozy
Cytotoxic edema causes….and the outcome is….
Altered cellular metabolism
IC accumulation of fluid into astrocytes-not moist or oozy
If the edema is severe and has a long duration, what will be the brain look like?
Gyri are swollen and flattened, sucli are shallow, displacement due to inc in volume
What is lipping of the cerebellum
Medulla oblongata and the posterior portion of the cerebellum herniate through the foramen magnum.
What are the main lesions of inflammation
Pronounced vascular response
Perivascular cuffing
Neuronal degeneration/death
Gliosis
Demyelination
Abscesses of the CNS are more common in white/grey matter?
White
Where is a good culture medium for many bacteria?
CSF
What causes Thrombotic meningoencephalitis?
Histophilus spp
What is the hallmark microscopic lesion for TME
Vasculitis
Thrombosis AND septic infarction in the brain and other organs**
Which infection is ascending from the trigeminal nerve?
Listeria monocytogenes
Where does Listeria like to go?
Brain Stem!!!! medulla and pons
Which bacteria is circumscribed collections of mononuclear cells?*****
listeria
What causes glycosuria in lams?
Clostridium perfringes type D
What causes enterotoxemia in lambs? What else is it called
Clostridium perfringes type D
Focal symmetrical encephalomalacia
What are the patterns of Clostridium perfringes type D
Hemorrhage and softening of the BASAL GANGLIA,
Lysis and liquefactions of the white matter of the frontal gyri sparing only the U fibers.
Edema dz is?
Enterotoxemic colibacillosis of pigs
Bilaterally symmetrical encephalomalacia
