Neuropath 1 Flashcards
Neurons response to injury
Small energy stores
Neurons with the highest metabolic rate are the most susceptible to damage
Limited capacity to regenerate
Necrosis in response to hypoxia, excitotoxicity & hypogly
Accumulate inclusion bodies in response to viral/degen
Chromatolysis
Loss of nissl substance
Axon response to injury
Wallerian or like degen - swelling
Response to trauma = wallerian
Ischemia/degeneration = wallerian - like
Segmental swelling - spheroids
Distension of myelin sheaths (Swiss cheese)
Macrophage infiltrates
Necrosis of neuropil
Malacia - softening of nervous tissue, only applies to gross pathology - result of extensive necrosis
Gitter cells (macro) clean up
Replaced by glial scar or cystic cavity
Edema in the brain
Vasogenic - fluid leaking from BV into intracellular space
Cytotoxic - intracellular, abnormal accumulation of fluid into brain cells and cell swelling and is commonly observed in cerebral ischemia & liver failure
Interstitial - fluid leaking between the ependymal lining and neuropil
Classification of neurological disease
Anomalies
Metabolic - toxic
Vascular
Inflammatory
Traumatic
Idiopathic
Neoplastic
Degenerative
Classification of neurological disease
Anomalies
Anomalies/malformations
Deviation of normal anatomy
Neural tube closure
Defects of forebrain induction
Neuronal migration disorders
Proliforation or size
Encephaloclastic defects
Hydrocephalus
Fluid has accumulated in the ventricle systems
Two kinds, communicating and non communicating
Communicating hydrocephalus
Bilateral, symmetrical dilation of the ventricular system without any lesions or obstruction of CSF
Must be accompanied by clinical neurological signs
Non-communicating hydrocephalus
Present or partial obstruction of CSF flow
Most common location for hydrocephalus
Mesencephalic aqueduct
Inflammation in mesencephalon during development can lead to scaring or dilation of tissues which become filled with fluid
Hydranencephaly
Accumulation of water within the brain matter
Destruction of preexisting cerebrum
Massive bilateral, systemic necrosis
Typically caused by transplacental viral infections
Cerebral hypoplasia
Never fully formed cerebella
Heritable in dogs and Arabian horses
Common in cats, cattle, sheep & pigs due to transplacental viral infections
Disease that causes cerebellar hypoplasia in cats
Panluekopenia
Disease that causes cerebellar hypoplasia in cattle
BVDV
Spina bifida
Spontaneous failure of closure of neural tube
Typically caudal spine
Dorsal defect in closure of one or several vertebral arches
Meningocele
Herniation of meninges
Meningomyelocele
Herniation of meninges and spinal cord
Hydromyelia
Dilation of central canal
Similar to hydrocephalus
Syringomyelia
Congenital or aquired
Formation of a cyst in the spinal cord
Cyst is not lined by ependymal cells and is separate from central canal**
Anomalies / malformations
Hydrocephalus
Hydranencephaly
Cerebellar hypoplasia
Spina bifida
Hydromyelia
Syringomyelia
Metabolic and toxic lesions
Usually acute
bilateral and symmetrical
Affect specific regions of the brain or SC
Major patterns
- necrosis
- selective necrosis or loss of neurons, axons or myelin
- spongiosis
Toxins
Organic
Inorganic
Natural occurring toxins
Endogenous toxins with organ failure
Polioencephalomalacia
Yellowing of gray matter
Laminar cortical necrosis of superficial cerebral cortex
Necrosis of neurons w edema in band-like patterns
Polioencephalomalacia in LA
Sulfur or lead in toxic
Thiamine deficiency
Hypernatremia
Polioencephalomalacia in SA
Hypoglycemia
Seizure activity
Fun fact abt Polioencephalomalacia
Florenscenes under ultraviolet light
Thiamine deficiency in cats
Occurs w ingestion of foods high in thiaminase
Necrosis of gray matter around ventricles of caudal colliculi
Equine leukoencephalomalacia
Moldy corn disease - consumption of grain w fungus Fusarium Moniliforme
Produces necrosis specifically in the white matter
Lesions are asymmetrical
Enterotoxemia
Pulpy kidney disease
Focal symmetrical encephalomalacia
High carb diet = overgrowth of clostridia in GIT
Necrotoxicity due to epsilon toxin which causes vascular damage and neuronal excitotoxicity
common location for necrosis with clostridium enterotoxemia
Base of internal capsule
Focal & bilateral
Poliomyelomalacia
Selenium toxicosis in pigs
Affects cervical lumbar intumescence
Causes focal, bilateral, symmetrical necrosis of ventral horns
