Martin: Intro, CV disease, & Infection Flashcards
Which cell type is evident 12-24 hrs after acute CNS hypoxic/ischemic insult?
Red neurons (“red dead guys”)
Morphology of red neurons
- Shrinkage of cell body
- Pyknosis of nucleus
- Dissapearance of nucleolus
- Loss of nissl substance
- Intense eosinophilia of the cytoplasm
What are the hallmarks of subacute and chronic neuronal injury (i.e., degeneration)?
- Cell loss —> Apoptosis
- Reactive gliosis
What is gliosis?
Proliferation of astrocytes in response to brain injury
What is the axonal reaction?
Best seen where?
- Change observed in cell body during regeneration of the axon
- Best seen in anterior horn cells of SC when motor axons cut
Most important histopathologic indicator of CNS injury regardless of etiology?
Characterized by what 2 things; what cell?
- Gliosis
- BOTH hypertrophy and hyperplasia of astrocytes
Which cells of the CNS are most sensitive to insult?
- Pyramidal neurons (hippocampus)
- Neocortical Betz cells
- Cerebella purkinje cells
Intracellular inclusions seen in herpes, rabies and cytomegalovirus?
Where specifically in the cell is each seen?
- Cowdry body (intranuclear): herpes
- Negri body (intracytoplasmic): rabies
- Both nucleus and cytoplasm: CMV
Intracytoplasmic inclusions seen in Alzheimer’s and Parkinson disease?
- Neurofibrillary tangles: Alzheimer’s disease
- Lewy bodies: Parkinson’s disease
__________ act as the metabolic buffers and detoxify the brain; also contributing to the BBB (foot processes)
Astrocytes
What is the intermediate filament found in Astrocytes and can be stained for?
GFAP
Gliomas are positive for which stain?
GFAP
What type of astrocyte is seen in pt’s with long-standing hyperammonemia due to chronic liver disease (will have flapping tremor of hands with extension of the wrist, asterixis), Wilson disease, or hereditary metabolic disorders of the urea cycle?
Alzheimer Type II Astrocyte
What type of cytoplasmic inclusion bodies are characteristic of Pilocytic Astrocytoma and also found in regions of long standing gliosis?
Rosenthal fibers
Which heat-shock proteins are found in Rosenthal Fibers?
- αB-crystallin
- hsp-27
*Also ubiquitin
What is Alexander disease and what cellular changes are seen in this disease?
- Leukodystrophy due to mutation in GFAP
- Rosenthal fibers, but more commonly seen are corpora amylacea (aka polyglucosan bodies)
Corpora amylacea (aka polyglucosan bodies) are positive for which stain?
PAS positive
______ are mesoderm derived phagocytic cells that serve as resident macrophages of the CNS
Microglia
Which round, faintly basophilic, concentrically lamellated structures increase with age and are though to represent degenerative changes in the astrocyte?
Corpora amylacea (aka polyglucosan bodies)
What are the cell surface markers of Microglia?
CR3 and CD68
What are 4 ways microglia respond to injury?
1) Proliferation
2) Dev. elongated nuclei (rod cell), as in neurosyphillis
3) Microglial nodules: microglia aggregate around small foci of necrosis
4) Neuronophagia: microglia congregate around cell bodies of dying neurons
How does the myelination ability of oligodendrocytes differ from schwann cells?
- Oligodendrocytes myelinate numerous internodes on multiple axons
- Schwann cells in peripheral nerve, has a one-to-one correspondance between cells and internodes
Injury or apoptosis of __________ cells is a feature of acquired demyelinating diseases and leukodystrophies?
Oligodendroglial cells
What are Ependymal cells and where are they found in the CNS?
Ciliated columnar epithelial cells lining the ventricles
Disruption of the ependymal lining and prolferation of subependymal astrocytes produces what on ventricular surfaces?
Ependymal granulation
Which agent may produce extensive ependymal injury, with viral inclusions in ependymal cells?
CMV
What is the response of microglia to neuronal injury?
Proliferate and accumulate during CNS injury
What is Vasogenic edema and is often seen following what?
- Increased EXTRAcellular fluid due to BBB disruption and increased vascular permeability
- Fluid shifts from INTRAvascular compartments to INTERcellular spaces
- Can be either localized (i.e., adjacent to neoplasms or inflammation) or generalied often follows ischemic injury
What is Cytotoxic edema and when is it seen?
- Increase in INTRAcellular fluid secondary to neuronal, glial, or endothelial cell membrane injury
- Generalized hypoxic/ischemic insult or w/ metabolic derangment
What is the most common cause of noncommunicating (obstructive) hydrocephalus in the neonate/infant?
Aqueductal stenosis
Enlargement of the entire ventricular system (“symmetric dilation”) due to accumulation of CSF not being properly absorbed at the dural sinus level is known as?
Communicating (“non-obstructive”) hydrocephalus
What 2 congenital conditions cause ventricular system obstruction?
1) Acqueductal stenosis
2) Dandy-Walker malformation
What is Hydrocephalus Ex-Vacuo?
Whom is it seen in?
What is the CSF pressure?
- Compensatory increase in ventricular volume secondary to loss of brain parenchyma
- Atrophy with increasing age, stroke or other injury, chronic neurodegenerative disease
- CSF pressure is NORMAL!!!
Herniation is displacement of brain tissue due to _____ or ______
Mass effect or Increased intracranial pressure
Subfalcine herniation involves displacement of the _______ under the _______
Cingulate gyrus under the falx cerebri
Subfalcine herniations can compress which vessel?
Anterior cerebral artery
Transtentorial (uncinate, mesial temporal) herniation occurs when?
Which specific part and of which lobe?
MEDIAL aspect of the TEMPORAL lobe is compressed against the free margin of the tentorium
What are 3 possible consequences of progression of transtentorial herniations?
1) Compression of CN III —> pupillary dilation; eye is “down and out” (ipsilateral to lesion)
2) Compression of PCA —> ischemia of primary visual cortex
3) Large herniation may compress contralateral cerebral peduncle —> hemiparesis ipsilateral to side of herniation = Kernohan notch = “false localizing sign”
What are Duret hemorrhages and are a result of what?
- Progression of transtentorial herniation producing secondary hemorrhagic lesions in the midbrain and pon
- “Flame-shaped” lesions
What are congenital causes of hydrocephalus?
- Intrauterine infections (TORCH)
- Agenesis/atresia/stenosis
- Arnold chiari malformations
- Dandy walker syndrome
- Cranial defects: Achondroplasia and Craniostenosis
What is the most common parasitic nervous system disease in the world and can lead to hydrocephalus?
- Cysticercosis
- Taenia Solium (pork tapeworm)
What are the characteristic of normal pressure hydrocephalus and who is it seen in?
- Symmetric type usually occuring in adults >60
- Develops slowly over time; drainage of CSF is blocked gradually
- Wet (incontinence), Wacky (dementia), Wobbly (ataxia)
A right hemisphere trans-tentorial herniation, causes a Kernohan’s notch in the _____ cerebellar peduncle, which results in ________ motor impairment.
A right hemisphere trans-tentorial herniation, causes a Kernohan’s notch in the left cerebellar peduncle, which results in right-sided motor impairment.
What is a tonsillar herniation and why is it life threatening?
- Displacement of the cerebellar tonsils through the foramen magnum
- Can can brainstem compression and compromises vital respiratory and cardiac centers in the medulla
_______ refers to a diverticulum of disorganized brain tissue extending through a defect in cranium; most often occurring in the posterior fossa
Encephalocele (sometimes misleadingly referred to as a “nasal glioma”)
Malformation of the anterior end of the neural tube leading to a “frog-like” apperance of a fetus is known as?
Anencephaly
The cause of Microcephaly is linked to?
- Chromosomal abnormalities
- Fetal alcohol syndrome
- HIV-1 acquired in utero
- Zika
What is Lissencephaly and the 2 general patterns observed?
- Reduction in the # of gyri; sometimes agyria = NO gyri
What term describes neurons in innaprpriate places?
Neuronal heterotopia: assc w Epilepsy
Which forebrain anomaly is characterized by small, unusually numerous, irregularly formed cerebral convolutions? Leads to extra thick cortex
Polymicrogyria
What is Holoprosencephaly? Severe forms produce which abnormalities?
- Incomplete separation of the cerebral hemispheres across the midline
- Cyclopia from midline abn
- Arrhinencephaly from absence of olfactory CNs
Holoprosencephaly is associated with what disease and signaling mutation?
- Trisomy 13
- Sonic hedgehog signaling pathway
Radiologic imaging showing a “bat wing” deformity is associated with that condition?
Agenesis of the corpus callosum
What is an Arnold-Chiari Type II malformation and what other abnormalities is it associated with?
- Type 2 = more severe
- Vermis extends down into foramen magnum
- Assc w hydrocephalus and myelomeningocele
What is an Arnold-Chiari Type I malformation?
- Type 1 = less severe & sometimes asymptomatic
- Cerebellar tonsils extend down vertebral canal
- May present w HA’s if CSF flow is impaired
Which condition is associated with an enlarged posterior fossa, absence of cerebellar vermis w/ replacement by a large midline cyst representing an expanded roofless 4th ventricle?
Dandy-Walker Malformation
Which condition has hypoplasia of the cerebellar vermis, elongation of the cerebellar peduncle and an altered shape of brainstem; together giving a ‘molar tooth sign’ on imaging?
Joubert syndrome
Syringomyelia is associated with what other condition; how does it present?
What part of the spinal cord is involved?
- Associated w/ Arnold-Chiari Malformations
- S/s: pain & temp loss of both UE (cape-like syrinx)
- Central canal of spinal cord grows, interrupting the fibers in the anterior white commisure
Expansion of the ependyma-lined central canal of the spinal cord is known as ________.
Hydromyelia
What is Cerebral Palsy and what are the clinical manifestations of this disease?
Occurs due to insults during which period?
- Non-progressive neurologic motor deficits characterized by combination of spasticity, dystonia, ataxia/athetosis, and paresis
- Pre-natal and perinatal periods (are present from birth)
What type of hemorrhage is seen in the germinal matrix of premature infants?
- Intraparenchymal hemorrhage
- Junction between thalamus and caudate nucleus
- May extend into ventricles —> subarachnoid space —> hydrocephalus (obstructive)
Infarcts may occur in the supratentorial white matter of premature infants and are known as?
Characteristic finding?
- Periventricular leukomalacia
- Chalky yellow plaques = white matter necrosis and calcification
Extensive ischemic damage of both white and gray matter leading to large cystic lesions during the perinatal period is known as?
- Multicystic encephalopathy
Diastatic fracture
Fracture that crosses a suture
Clinical term for altered consciousness secondry to a head injury typically brough about by a change in momentum of the head
Concussion
What is the morphology of a brain contusion?
- Wedge shaped w/ a broad base lying along the surface at the point of impact
What term describes an old traumatic lesion?
Term for contusion at point of impact and the opposite of that?
- Plaque Jaune: old lesion. Yellow/brown patches.
- Coup: contusion at point of impact
- Contrecoup: contusion on opposite of side impact bc of sudden decel
Diffuse axonal injury is best demonstrated using what lab techniques/stains?
- Silver impregnantion (silver stain)
- Immunoperoxidase stains for amyloid precursor protein and α-synuclein
Sudden onset of severe headache (“worst headache of my life”), often with rapid neurologic deterioration is consistent with a _________ hemorrhage
Subarachnoid