Neuro Pathology Flashcards
List the 8 unique histopathologic rxns seen in nervous tissue.
- Chromatolysis
- Demyelination
- Wallerian degeneration
- Satellitosis
- Neuronophagia
- Perivascular cuffing
- Malacia
- Neuronal inclusion bodies
What are pale areas in neuronal cytoplasm due to dispersion of Nissl’s substance are known as?
Chromatolysis
Which NS cell types can divide?
Implications?
Glial cells
(Only these cells can become tumors.
Neurons CANNOT)
Distemper virus shows an affinity for which NS cell type?
Oligodendrocytes
Which supporting cell type produces myelin?
Oligodendrocytes
Which supporting cell type controls
CSF movement?
Astrocytes
Which 2 NS cell types may become neoplastic?
- Glial cells
- Ependymal cells
What condition describes disruption & phagocytic removal of myelin?
Which cells in the PNS can fix this?
- Demyelination
- Schwann cells
What is the term for destruction of the axon & myelin sheath following trauma or toxic injury?
Where can it regenerate?
- Wallerian Degeneration
- PNS
What is the term for the accumulation of glial cells around damaged neurons?
Which type of glial cells mainly?
- Satellitosis
- Microglia
What is the term for MØic phagocytosis
of necrotic neurons?
Neuronophagia
What is the term for accumulation of polymorphonuclear or mononuclear leukocytes in Virchow-Robin spaces?
Perivascular cuffing
What type of leukocytes are suppurative?
polymorphonuclear
What type of leukocytes are non-suppurative?
Mononuclear
What does malacia refer to?
softening & liquefaction of NS tissue from necrosis of neurons & glial cells
What do Cowdry Type A inclusion bodies look like?
What virus are they often associated with?
- eosinophilic
- usually single & displaced nucleolus
- Herpes virus
What do Cowdry Type B inclusion bodies look like ?
What 2 viruses are they associated with?
- Eosinophilic
- often multiple & necleolus is NOT displaced
- Polio & Adenovirus
What is Cerebral/spinal dural osseous metaplasia (Ossifying pachymeningitis) & who gets it?
- ovoid, thin whitish to mottled red metaplastic plates of bone (due to hemopoietic tissue)
- incidental finding in old dogs
List the 5 congenital anomalies that are the result of neural tube closure defects (dysraphia).
- Anencephaly
- Cerebral aplasia (prosencephalic hypoplasia)
- Meningoencephalocele
- Meningomyelocele
- Hydromyelia
Pathogenesis of Anecephaly?
- absence of the cerebral hemispheres w/ failure of forebrain fusion
- Medulla & mesencephalon usually still persists
Congenital anomalies resulting from injury during the last trimester of gestation are due to what?
prominent inflammatory changes
List the 2 Neuronal Migration disorders.
- Lissencephaly
- Hydrocephalus
Pathogensis of Prosencephalic Hypoplasia?
Who gets?
(AKA Cerebral aplasia)
- Failure of bilateral seperation of hemispheres resulting in a SINGLE central ventricle
- NO cerebral hemispheres
- Pigs & lambs
Pathogensis of Meningoencephalocele?
- protrusion of brain & meninges through a defect in the cranium
- almost always median, along suture lines
- associated with crania bifidum
Pathogenesis of Meningomyelocele?
Who gets?
- protrustion of Spinal cord & meninges
- associated with spina bifida
- Brachycephalic breeds of dog
- Manx cats
Pathogenesis of Hydromyelia?
- excess CSF in spinal cord canal
Lesions of Prosencephalic hypoplasia?
(Cerebral aplasia)
- absence of cerebral hemispheres
- single central ventricle
- cyclopia → severe cases (pigs & lambs)
- Abscence of telencephalon
DDX of Cerebral aplasia?
(2)
- Anencephaly
- Hydraencephaly
Pathogenesis of Meningocele?
Who gets?
- protrusion of fluid-filled meninges
- Pigs → inherited
- Cats → Burmese or pregant queens TXed w/ Griseofulvin
Etiopathogenesis of Lissencephaly (agyria)?
- Lhasa Apso
- absence of 1° gyri → “smooth brain”
- excessively thin cerebral cortex
List the 3 different types of Hydrocephalus.
- Internal → ventricles
- External → sub-arachnoid space
- Communicating → ventricles + sub-arachnoid space
(where the fluids accumulates)
List the 3 animals in which Hydrocephalus is of no clincal signifcance.
- Early fetus
- Aged animals
- Brachycephalic breeds
How is Hydrocephalus ex vacuo different from Hydrocephalus?
due to compensatory enlargement of CSF spaces
NOT the result of increased CSF pressure
Etiopathogenesis of Congenital Hydrocephalus?
- idiopathic & develops during fetal life
- associated w/ Malformation
- To due:
- intra-uterine infections
- nutritional deficiency
Eitopathogenesis of Acquired Hydrocephalus?
- most often internal hydrocephalus → obstructed CSF flow
- Progressive w/ NO cranial malformation
- Sequel to: inflammation, cholesteatoma, neoplasia & parasitic cysts
Pathogenesis of Hydrocephalus?
- increased production of CSF
- obstruction of CSF flow
- defective absorption of CSF
Lesions of Congenital vs. Acquired Hydrocephalus.
TQ
Congenital
- Lateral ventricular distention
- enlarged cranium
Acquired
- Lateral ventricular distention
- NO cranial malformation
- Pressure atrophy → white matter + cerebral cortex
Etiopathogenesis of Hydranencephaly?
- Etiology → Viral infections
- Path → results from severe encephaloclastic (destructive) effects
-
Lesions:
- Ø cerebral hemispheres
- membranous CSF
- Leptomeninges filled sacs
Pathogenesis of Porencephaly?
-
Path:
- less severe case of hydranencephaly
- destructive process in PRENATAL life
-
Lesions:
- Cysts
- White matter defects of cerebral hemispheres
Etiopathogenesis of Cerebellar Hypoplasia?
-
Etiology → Viral or Inherited
- Feline panleukopenia
- BVD
- CHV
- Path→ malformation of cerebellum w/ loss of Perkinje & Granular cells
Etiopathogenesis of Syringomyelia
- Etiology → rare, except Weimaraner
-
Path→malformation of the spinal cord
- tubular cavity (syrinx) that extends over several LUMBAR segments
Lesions of Syringomyelia
(3)
- Cysts in central Gray Matter
- NOT lined by ependymal cells
- Weimaraner → hopping gait
Pathogenesis of Abiotrophy
(Cerebellar atrophy)
- 1° metabolic defect/degeneration → premature apoptosis
- involves only cerebellar cortex or multisystem
- Non-inflammatory dz.
Lesions of Abiotrophy
- Loss of Purkinje & Granular cells
- Seen in basal ganglia → caudate nuclei, putamen, olivary nuclei, & substania nigra
Give 5 examples of TSE’s (prion dz) & species they affect.
- Scrapie → small rumis
- BSE → cattle
- FSE → cats (BSE in cats)
- CWD → free ranging deer
- Transmissible mink encephalopathy
Lesions of
Transmissible Spongiform Encephalopathies
(TSE).
- NO INFLAMMATION!!
- Cytoplasmic vacuoules & astrocytosis
- + Spongiform changes
- PrPSC protein
How do you DX TSE’s?
- Abnormal protein + lesions → OBEX of brainstem
- IHC → before CNS lesions
- 3rd eyelid, tonsils, retropharyngeal LN
Etiopathogenesis of Globoid Cell Leukodystrophy
(a Lysosomal Storage dz)
- Etiology → inherited defect of galactocerebroside-B-galactosidase
-
Path → Accumulation of Galactocerebroside
- MØs (microglial cells) → Globoid cells
- neurotoxic → CNS signs (@ 2-7 mo. old)
Lesions of Globoid Cell Leukodystrophy
- WHITE matter becomes gray & soft
- PAS (+) globoid type MØs
4 things that can cause Brainstem Lesions
- Prions → obex
- Listeriosis → medulla & pons
- Shiga-like toxin from E. coli
- Cu deficiency
Vit. E deficiency in birds affects what area of the brain?
Cerebellum
Acute Pb toxicity in Dogs affects what 2 regions of the brain?
Cerebrum & Cerebellum
Broad etiology of Malacia
(necrosis of CNS tissue)
- Vascular
- Hypoxia
- horse → post anesthesia
- Toxins
- Infections
- Nutritional
List the Toxins that can cause Malacia and
the form of malacia seen with each.
- Yellow Star Thistle → nigropallidal
- Pb, Salt, Se → poliomyelomalacia
- Moldy corn → leukoencephalomalacia
- HORSE
List the 2 protozoal infections that cause malacia.
- Theileriosis
- Babesiosis
- DOGS
What CNS disease is seen in Sheep as a result of
C. perfringens D infection?
Focal Symmetrical Encephalomalacia
(FSE)
What 2 Nutritional deficiencies lead to malacia?
- Vitamin → cerebral hypoxia
- A, B1, E
- Mineral
- Copper
What 4 things cause Focal Malacia?
- FSE
- Equine leukoencephalomalacia
- Equine Nigropallidal encephalmalacia (YST toxicity)
- Avian encephalomalacia (Vit E deficiency)
(associated w/ a specific toxin)
Susceptibility of cell types to
Laminar Cortical Necrosis (due to hypoxia) ?
Neurons > Oligodendrocytes>Astrocytes> Microglia
(NOAM)
2 things that cause Cerebrocortical necrosis (a form of laminar cortical necrosis)
- Chronic Pb poisoning → cattle
- Thiamine deficiency → cats & cattle
What causes Bilateral Polioencephalomalacia?
(form of laminar cortical necrosis)
Acute Se toxicity→ pigs
What are 2 causes of Polioencephalomalcia?
- Salt toxicity → pigs
- Thiamine deficiency → cats & cattle