Section 1
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TDP-43 staining
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Last updated
6 years ago
Date created
Mar 1, 2020
Cards (76)
Section 1
(50 cards)
TDP-43 staining
normally stains only nucleus, but in ALS, stains cytoplasm as well!
microglial cells
extremely small glial cells that remove cellular debris from injured or dead cells derived from bone marrow can for "microglial nodules" or transform into histiocytes/Gitter Cells
Lipohyalinosis and microatheromas
destructive vessel lesion characterized by loss of nml aterial architecture, mural foam cells; accum of lipid-laden MO w/ in itimal layer of vessel . Assoc with lacunar infarct.
AVMs microscopically
thick walled arteries of various SM proliferation, collagen deposition, and duplication of internal elastic membrane thick walled-"arteriolized" veins Gliotic CNS tissue b/w abnormal blood vessels
Berry aneurysm microscopic findings
may contain thrombotic material fibrocalciferous plaque material neck of sac has hyalinized collagenous tissue
CAA microscopically
leptomeningeal and cortical areas will show accumulations of eosinophilic material will see loss of vascular smooth muscle and double barreled contour apple-green bifringence of amyloid under polarizing illumination or protein immunohistochemistry
vascular dementia gross findings
cerebral atrophy and ex vacuo hydrocephalus from reduction in white matter multifocal lacunar infarcts
Lacunar infarcts
hypertension affects deep penetrating arteries/arterioles supplying basal ganglia, deep white matter, and brainstem locations (in desc. order of freq.): lenticular nucleus, thalamus, internal capsule, deep white matter, caudate nucleus, pons single or multiple, small, cavitary infarcts <15mm
Most vulnerable regions of hypoperfusion/hypoxia in brain
Hippocampal pyramidal cells of Sommer's sector (CA1) Cerebellar purkinje fibers Pyramidal neurons in cerebral cortex layers
interstitial edema in brain
due to obstructive hydrocephalus
Adrenoleukodystrophy microscopically
will see prominant perivascular collections of lymphocytes and macrophages - macrophages appear very dark red and "blobby" as they are ingesting lots of fat will also appear foamy and some will appear in multilayered-spiral appearance
Myelin stain
stains myelin a deep blue (white matter!)
Methanol poisoning
Symptoms: Severe metabolic acidosis, retinal damage (blindness) will see extensive hemorrhage in putamen - extensive necrosis can be seen microscopically as well
ALS clinical features
evidence of LMN degeneration by clinical, electryphysiological, or neuropathological exam evidence of UMN degen by clinical exam progression of the motor syndrome within one region to the next through history or examination
Neuronal responses to injury
Central Chromatolysis: swollen neuron that has lost Nissl substance - seen w/axotomy Eosinophilic Change: "Red Neuron" change seen w/hypoxic-ischemic injury
vascular dementia microscopic findings
extensive atherosclerotic or hypertensive microvascular changes hyaline arteriolosclerosis lipohyalinesclerosis
cytotoxic edema
secondary to neuronal, glial, or endothelial cell injury failure of cellular Na-k pump leads to swelling
ALS pathogenesis
TDP-43 is central to pathogenesis - pathological accumulation of this protein - form inclusion bodies Familial forms show mutations in TARDBP gene - other forms have irregular proteins that interact with TDP-43, leading to accumulation link w/FTLD-TDP
Non-thrombotic emboli
tumor, fat, air
AVMs
arterial venous malformation, occurs when arteries or veins come together improperly and are weaker When one of these forms, the probability of a hemorrhage increases by 1% every year affect MCA > ACA > PCA
Astrocytes
Provide structural and metabolic support for neurons react to injury make the BBB regulate ion/neurotransmitter concentration fibrillary and gemistocytic morphologies
amyotrophic lateral sclerosis (ALS)
Degeneration upper and lower motor neurons - substantia nigra, spinocerebellar tracts, dorsal columns and autonomic system all affected sporadic (90-95%) and familial forms
Watershed infarcts
at the border between major cerebral circulations (typically MCA and ACA -> linear para-sagittal infarct) -> vasospasm, associated with hypotension, association with hypoxic-ischemic encephalopathy -> wedge shaped
Thiamine deficiencies
Beriberi and Wernicke's encephalopathy seen in chronic alcoholics and developing countries
time course changes w/ischemia: microscopic
24 hours-2 weeks: - tissue necrosis - influx of macrophages, vascular proliferation, reactive gliosis - reactive astrocytes can easily be seen repair: after 2 weeks - removal of necrotic tissue and loss of normal architecture w/gliosis
Adrenoleukodystrophy grossly
myelin loss in posterior lobes also damage corpus collosum will spare the U-fibers
Time course changes in gross appearance of brain during ischemia
diffuse brain swelling with widened gyri and narrow sulci necrosis of vulnerable regions laminar necrosis of cerebral cortex
vasogenic edema
swelling caused by inflammatory response in the subarachnoid space causing increased vascular permeability
Wallerian degeneration
degeneration of the distal portion of the axon and myelin sheath
PML microscopic appearance
foamy macrophages bizarre astrocytes very sparse lymphocytes due to immune suppression! will also see enlarged oligodendroglial nuclei with ground glass appearance
Transtentorial herniation
medial aspect of temporal lobe is compressed against the free edge of the tentorium and herniates underneath it will see CNIII compromise w/pupillary dilation and impaired ocular movements on side of herniation can compromise PCA
vascular dementia
disease caused by numerous small cerebral vascular accidents symptoms: gait abnormalities, dementia, pseudobulbar signs, will see multiple bilateral, gray matter and white matter infarcts
pseudolaminar necrosis
neuronal loss and gliosis is uneven
Cerebral amyloid angiopathy (CAA)
Beta-amyloid deposition in walls of cortical and leptomeningial arteries - predisposes patients to lobar hemorrhages accounts for 12-15% of all cerebral hemorrhages in elderly
Wernicke's encephalopathy
Gaze palsies Ataxia (respond to thiamine administration) Korsakoff's psychosis - retrograde and anterograde amnesia - confabulation - irreversible normally see lesions in mammilary bodies - also see in PAG and thalamus microscopically, can see hemosiderin-laden macrophages due to the microhemorrhages - will also see breakdown of myelin - spongy and gliotic as well
MS microscopic pathology
will see loss of staining of myelin (luxophilic) will see lots of lymphocytes and macrophages - macrophages will be "foamy" at edges of plaques Will see variation in disease activities in plaques - some parts will by hypercellular and others will be hypocellular shadow plaques will appear intermediate staining b/w myelination and demyelination inactive plaques show as hypocellular areas w/loss of oligodendrocytes, sharply defined margins, and axonal loss (shortened and less dense)
ALS microscopic findings
Loss of motor neurons and astrocytosis in the brain, spinal cord, and motor cortex bunina bodies: small, eosinophilic inclusions, 2-5 micrometers in diameter that are in small beaded chains - sparse in most ALS cases Neuronal, hyaline inclusion bodies that are large and homogenous, often displacing NIssl substance many other inclusions that can be seen when staining for ubiquitin or nucleoporin 62 Resemble LEWY bodies (Parkinson's), so you must identify which stain you are using!
Acute hypertensive hemorrhage
distribution of lenticulostriate branches of MCA perforating arterioles to the pons of basilar artery most often affects deep cerebral nuclei (putamen, thalamus, caudate nucleus)
Tonsillar herniation
Displacement of the cerebellar tonsils through the foramen magnum can compromise respiratory and cardiac centers medulla
cavernous angioma
abnormal collection of thin-walled vascular channels w/out intervening brain parenchyma - no intervening brain tissue young adults most commonly affected - 1/4 of patients are children 1/3 of patients present w/focal epilepsy
chronic changes to gross brain
cavitation of infarcted areas due to liquifactive necrosis residual reactive astrocytes form a gliotic scar at infarct edges
PML gross appearance
will often see confluent discoloration of gray foci in cortex and white matter - generally unilateral - can see necrosis
Intracellular inclusion bodies
can be intranuclear on cytoplasmic reflect underlying disease process
Cerebral amyloid angiopathy clinical features
depends on size of hemorrhage - range from massive stroke to progressive dementia parietal lobe involvement can result in contralateral "neglect" syndrome commonly found in individuals w/alzheimer-like neurofibrillary pathology
Spontaneous intracranial hemorrhage
Hypertension most important cause! peak incidence in over 60 years and more common in men
Subfalcine (cingulate) herniation
Asymmetric expansion of a cerebral hemisphere displaces the cingulate gyrus under the edge of the falx (a large fold of the dura mater). These herniations can be associated with compression of the anterior cerebral artery).
microscopic changes with ischemia
no apparent changes in first 12 hours 12-24 hrs: - eosinophilic changes in neurons ("red neurons") - similar thing happens to glial cells - influx of neutrophils after 24 hours
ALS gross findings
anterior nerve roots appear shrunken and gray when compared to the posterior afferent roots may show spinal cord atrophy frontal and temporal lobe atrophy in patients w/dementia
MS gross appearance
plaques in (what should be white matter) appear darkish brown/black - often in optic nerves and adjacent to ventricles can see loss of stained myelin (should be blue) tends to prefer posterior column of spinal cord
Shower embolization
Fat embolism after fracture
Section 2
(26 cards)