Intro To Neuro Pathology Flashcards
In the central nervous system, myelinating cells are called…
Oligodendrocytes
What is selective vulnerability
set of neurons sharing one or more properties demonstrating response to one insult
Describe the acute “red neuron” response to injury
Seen at 12- 24 hrs
earliest sign of insult
Shrinkage of cell body
Pyknosis
Loss of nucleolus and nissl substance
Intense eosinophilia
Describe the subacute and chronic response of neurons to injury
Cell loss and reactive gliosis (like scar tissue but is NOT scar tissue)
Describe Axonal Reaction
Increased protein synthesis associated with axonal sprouting
- enlarged cell body
- Peripheral displacement of nucleus
- enlarges nucleolus
- Nissl removed from center of cell to periphery (central chromatolysis)
Describe intracytoplasmic and intranuclear inclusions
Intracytoplasmic: lipofuscin, proteins, or carbohydrates
– Rabies, lewy bodies, CJD
Intranuclear: Herpes Cowdry body. CMV( both nuclear and cytoplasmic)
What is the most important histopathologic indicator of CNS injury
Gliosis, regardless of etiology
- -Hypertrophy & Hyperplasia of astrocytes
- -Astrocytes act as metabolic buffers & detoxifiers in the brain
- -Foot processes contribute to BBB
Describe the characteristics of gemistocytes
Enlarged nuclei, becomes vesicular with prominent nucleoli, cytoplasm expands, BRIGHT PINK & dislocates nucleus eccentrically.
What is an Alz Type 2 Astrocyte
NOTHING TO DO WITH ALZ DISEASE
Gray matter cell, 2-3X nucleus, pale staining central chromatin, intranuclear glycogen droplet, prominent nuclear membrane & nucleolus.
Hepatic Encephalopathy and Wilson Dz
Describe Rosenthal fibers
Thick, elongated, brightly eosinophilic, irregular structures occurring within astrocytic processes (benign and slow)
- -contains HSP
- Areas of long standing gliosis: Pilocytic Astrocytoma (Alexander Dz)
Describe corpora amylacea
HINT OGRES are like ONIONS (slide 20 lecture1)
Polyglucosan bodies (PAS+)
Round faintly basophilic, concentrically laminated strictures located adjacent to astrocytic end processes
Contain glycosaminoglycan polymers, HSP, and ubiquitin - increase with age and degen
What is the function of microglia
macrophages of the CNS
surface CR3 & CD68 markers
Differentiate Microglial nodules vs Neuronophagia
Microglial Nodules: Microglia Aggregate Around small foci of necrosis
Neuronopgia: Microglia congregate around dying neuron
What is the ependymal cell response to injury
leads to ependymal granulations
seen in CMV
What are the two types of cerebral edema
Vasogenic: Increase in extracellular fluid
Cytotoxic Edema: increase in intracellular fluid secondary to cell membrane injury
What is a hallmark finding of increased cranial pressure?
Papilledema
What pathogenic reason would occur that would result in increased production of CSF
Choroid plexus papilloma
How does pyogenic meningitis contribute to an increased ICP
Suppurative exudate covering brainstem
Thickened leptomeninges -> obstructive Hydrocephalus
What is communicating hydrocephalus
CSF is not absorbed properly at the dural sinus level thus the ventricles tend to be symmetrically dilated
What are the findings of Hydrocephalus Ex-vacuo and why might it be hard to tell
Dilation of ventricles
Shrinkage and atrophy of brain matter
CSF pressure is normal
What is the triad of Normal pressure hydrocephalus
Wet - urinary incontinence
Wacky - Dementia
Wobbly - Gait disturbance
What are the three kinds of cerebral herniation
Subfalcine - Cingulate gyrus under Falx
Transtentorial - Medial aspect of the temporal lobe compressed against tenorum (C3 disturbances)
Tonsillar - Cerebellar tonsils displaced through the foramen magnum - life threatening
Describe Kernohan’s phenomenon
compression of cerebellar peduncle against tentorium cerebelli -> ipsilateral deficit
Creates false localizing sign ex
Right hemisphere transtentorial herniation -> kernohan’s notch in left cerebellar peduncle -> right sided motor impairment
Describe a Duret Hemorrhage
progression of transtentorial herniation often with secondary hemorrhagic lesions in midbrain or pons
What form of necrosis does the brain undergo
Liquefactive
What type of defects account for most of the CNS malformations
Neural Tube Defects - failure to close by day 28
-Folate deficiency
What is myelomeningocele?
extension of CNS through the defect -> motor and sensory defects
what are some associated causes of Microcephally
Zika (remember when people were worried about that)
Fetal Alcohol Syndrome
HIV-1
What is a neuronal heterotopia
Commonly associated with epilepsy, collections of normal neurons in inappropriate places
Describe Chiari Type 1
Low lying cerebellar tonsils extend down into vertebral canal: silent unless CSF impeded
Describe Chiari Type 2
more severe, misshapen midline cerebellum with downward extension of vermis through F magnum
occurs with hydrocephalus and lumbar myelomeningocele
Describe Dandy walker malformation
Enlarged posterior fossa; expanded roofless fourth ventricle = cerebellar vermis absent or rudimentary
What buzzword sign is associated with Joubert Syndrome
Molar tooth sign
hypoplasia of vermis, elongation of cerebral peduncles
What is a syringomyelia
fluid-filled cleft like cavity in the inner portion of the cord
-classic sx syrinx: isolated loss of pain and temp sensation of upper extremities
what is hydromyelia
expansion of ependymal-lined central canal of the cord
Describe Intraparenchymal hemorrhage
Seen in germinal matrix of premature infants
most common perinatal brain injury
describe periventricular leukomalacia
infarcts in supratentorial white matter - premature infants; chalky yellow plaques = necrosis and calcification
what is a distatic fracture
fracture crosses a suture line
what are the signs of a basilar skull fracture
orbital or mastoid hematomas
Raccoon eyes
Oto/rhinorrhea: CSF drainage
What are some downstream effects of CTE on the brain
Microhemorrhages
Neurofibrillary tangles/amyloid and tau deposits
Depigmentation of substantia nigra
What is diffuse axonal injury
Axonal swelling +/- focal hemorrhaging lesions
direct action of mechanical forces. Do not NEED impact; angular acceleration sufficient
What is shaken baby syndrome
Shake a baby to stop it from crying
75-80% dont die but develop brain damage
How do we recognize shaken babies
Diffuse Axonal Injury
Subdural hematoma
Retinal hemorrhages
Child is never normal after the fatal shaking
