Neuropathology Central Flashcards
What characterizes a red neurons in acute neuronal injury?
- Shrinkage of the cell body2. Pyknosis of the nucleus3. Disappearance of the nucleolus4. Loss of Nissl (These granules are of rough endoplasmic reticulum (RER) with rosettes of free ribosomes, and are the site of protein synthesis) substance5. Intense eosinophilia of the cytoplasm
What is the histopathologic picture of axonal reaction?
CENTRAL CHROMATOLYSIS: 1. Enlargement and rounding up of the cell body, 2. Peripheral displacement of the nucleus3. Enlargement of the nucleolus4. Dispersion of Nissl substance from the center to the periphery of the cell
Match the ff inclusions with the disease:
- herpetic infection
- cytoplasmic inclusions, as seen in rabies
A. Cowdry body
B. Negri body
#Intracytoplasmic $Intranuclear
1A$ 2B#
When is the Alzheimer Type 2 Astrocyte usually seen?
Individuals with long-standing hyperammonemia due to chronic liver disease, Wilson disease, or hereditary metabolic disorders of the urea cycle.
What heat shock proteins are found in rosenthal fibers?
aB crystallin HSP 27
Rosenthal fibers are thick elongated brightly eosinophilic irregular structures that occur within astrocytic processes
What are seen in the cytoplasm of neurons in myoclonic epilepsy?
Lafora bodies
What are Duret hemorrhages?
hemorrhagic lesions in the midbrain and pons occurring during uncal herniation
What malformation can occur from mutations in the gene encoding the microtubule-associated protein LIS-1, which complexes with dynein and affects the function of the centrosome in nuclear movement?
Lissencephaly
What mutated genes in chromosome X causes neuronal heterotropias, collections of neurons in inappropriate locations along the migrational pathways?
Filamin A and Doublecortin
Where is misshapen lateral ventricles (“bat-wing” deformity) seen?
Agenesis of the corpus callosum
What is status marmoratus?
In perinatal ischemic lesions of the cerebral cortex, the depths of sulci bear the brunt of injury and result in thinned-out, gliotic gyri (ulegyria). The basal ganglia and thalamus may also suffer ischemic injury, with patchy neuronal loss and reactive gliosis. Later, aberrant and irregular myelinization gives rise to a marble-like appearance of the deep nuclei
Which TBI? clinical syndrome of altered consciousness secondary to head injury typically brought about by a change in the momentum of the head (when a moving head is suddenly arrested by impact on a rigid surface).
Concussion
What term is used to describe depressed, retracted, yellowish brown patches involving the crests of gyri most commonly located at the sites of contrecoup lesions (inferior frontal cortex, temporal and occipital poles)
Plaque jaune
When do the following events occur in subdural hematoma?1. Lysis of the clot 2. Growth of fibroblasts from the dural surface into the hematoma 3. Early development of hyalinized connective tissue
Lysis of the clot (about 1 week)
Growth of fibroblasts from the dural surface into the hematoma (2 weeks)
Early development of hyalinized connective tissue (1 to 3 months)
What is the percentage of % resting cardiac output going to the brain % of the total body oxygen consumption going to brain
15% of the resting cardiac output and accounts for 20% of the total body oxygen consumption.
What cells of the brain are the most susceptible to global ischemia of short duration?
- Pyramidal cells in CA1 of the hippocampus (Sommer sector)
- Purkinje cells of the cerebellum
- Cortical pyramidal neurons
What events happen after an infarct at the following timepoints:1. <24h2. 24h to 2 weeks3. More than 2 weeks
- <24h: red neurons
- 24h to 2 weeks: necrosis, macrophages, vascular proliferation
- More than 2 weeks: removal of all necrotic tissue, loss of normally organized CNS structure, and gliosis
When do phagocytic cells start to become the predominant type of cells in an infarcted region?
Phagocytic cells, derived from circulating monocytes and activated microglia, are evident at 48 hours and become the predominant cell type in the ensuing 2 to 3 weeks.
What is the size cutoff for lacunes?
These are lake-like spaces, less than 15 mm wide, which occur in the lenticular nucleus, thalamus, internal capsule, deep white matter, caudate nucleus, and pons, in descending order of frequency
What vascular changes are effected by hypertension?
Hypertension causes a number of abnormalities in vessel walls, including accelerated atherosclerosis in larger arteries; hyaline arteriolosclerosis in smaller vessels; and, in severe cases, proliferative changes and frank necrosis of arterioles chronic hypertension is associated with the development of minute aneurysms, termed Charcot-Bouchard microaneurysms, which may be the site of rupture
What amyloidogenic peptides deposit in vessel walls in CAA?
Abeta40
What protein is affected in CADASIL?
Notch 3 receptor
What is an aneurysmal sac composed of?
At the neck of the aneurysm, the muscular wall and intimal elastic lamina stop short and are absent from the aneurysm sac itself. The sac is made up of thickened hyalinized intima. The adventitia covering the sac is continuous with that of the parent artery.
What is the foix Jouanine disease?
Venous angiomatous malformation of the spinal cord and overlying meninges, most often in the lumbosacral region, associated with ischemic myelomalacia and slowly progressive neurologic symptoms.
What are rod cells?
When microglia responds to injury the nuclei elongate.
Acquired leukodystrophies primarily damage which cell in the brain?
Oligodendrocytes
What is the most benign form of spinal dysraphism?
Spina bifida occulta
When does the neural tube close?
Day 28 of embryonic developement.
Which undergoes radial migration from the germinal matrix to the cortex? Excitatory or inhibitory neurocons?
Excitatory. Respond to cell signal REELIN
Inhibitory neurons undergo tangential migration
Define1. Lissencephaly2. Polymicrogyria3. Neuronal heterotropia4. Holoprosencephaly
- Lissencephaly: reduction in the number of gyria
- Polymicrogyria: Small numerous gyria
- Neuronal heterotropia: Collections of neurons at inappropriate locations along the pathway of migration
- Incomplete separation of the cerebral hemispheres across the midline
What is characterized by an enlarged posterior fossa with a rudimentary vermis and a large midline cyst?
Dandy walker malformation
What area of the brain is most prone to bleeding in premature infants?
Germinal matrix in the junction of the thalamus and the caudate
What plaque is associated with old traumatic lesions? They are depressed retracted, yellowish brown involving the crests of the gyri.
Plaque jaune
What 2 staining methods are used for DAI to demonstrate axonal swelling?
- Silver impregnation
2. Immunoperoxidase stains for axonally transported proteins such as amyloid precursor protein and alpha synuclein
What vessel is involved in:
- Epidural
- Subdural
- Middle meningeal artery
2. Bridging veins
What histopathologic protein accumulation can be seen in chronic traumatic encephalopathy?
Tau containing NF tangles
What percentage of the brain accounts for1. Body weight2. Resting cardiac output3. Body O2 consumption
- 1-2%
- 15%
- 20% (20, O2 get it?)
What are the downstream cellular consequences of ischemia and hypoxia? First is the decrease in oxidative phosphorylation because of lack of o2 and mitochondrial damage followed by…
- Malfunction of the Na K ATPase sodium pump resulting in: efflux of K, influx of Ca resulting in activation of degrading enzymes (phospholipases, proteases, endonucleases), apoptosis induction, opening of the mitochondrial permeability transition pore and influx of Na resulting in water accumulation. Cellular swelling then commences
- Anaerobic glycolysis predominates effectively reducing pH leading to decreased activity of many enzymes and nuclear chromatin clumping
- Detachment of ribosomes resulting in reduced protein synthesis or misfolded proteins that then trigger the pro apoptotic proteins
- ROS species are formed by abnormal oxidative phosphorylation– damage adjacent molecules that are part of the membranes
What are the most sensitive neurons to global ischemic insults?
- Pyramidal cell layer of the hippocampus (CA1 sommer sector)
- Cerebellar purkinje cells
- Pyramidal neurons in the cerebral cortex
What are the layers of the cortex? Out to in
1 Molecular Layer: Axons and dendrites
2 External granular: Densely packed stellate and small pyramidal cells
3 External pyramidal: Loosely packed stellate cells and medium pyramidal cells
4 Internal granular: Densely packed stellate cells only
5 Internal pyramidal: Large pyramidal cells– giant pyramidal cells of Betz
6 Multiform: Multiple sized pyramidal cells with loosely packed stellate cells
In the cerebral cortex the neuronal loss and gliosis are uneven, with preservation ofsome layers and destruction of others, producing a pattern ofinjury termed ______
Pseudolaminar necrosis
In infarcted tissue state the order of appearnce:1. Eosinophilic neurons2. Neutrophils3. Macrophages4. Reactive astrocytes
- Eosinophilic neurons: First 12 hours
- Neutrophils: Up to 48 hours
- Macrophages: 48 hours to 3 weeks
- Reactive astrocytes: Starting 1 week to several months
What is etat crible?
Widening of the perivascular spaces without tissue infarction during arteriolar slcerosis?
What histopathologic vessel feature correlates with lacunar infarcts?
Arteriolar sclerosis
Size of lacunar infarct until?
15mm
AKA subcortical vascular dementia
Binswanger disease
What are the 2 processes that lead to HTN hemorrhages in HTN patients?
- Hyaline change in the vessels making them vulnerable to rupture
- Charcot Bouchard microaneurysms LESS THAN 300 MICROMETERS
What are the two ways to differentiate between arteriolar sclerosis with HTN VS vessel affected by amyloid angiopath?
- Deposition of amyloid in CAA2. NO FIBROSIS in CAA
Misfolding of the extracellular domain of the NOTCH3 receptor leads to what small vessel disease?
CADASIL: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy
What are the normal layers of vessels?
Tunica Intima: Endothelial layer, Basement membrane, Subendothelial layer, Internal elastic membrane
Tunica Media: Smooth muscle cells, external elastic lamina
Tunica Externa: Collagen fibers and vasa venorum
What vessel layers are missing in the sac of aneurysms?
Smooth muscle and internal elastic lamia
What mendelian disorders increase the risk for the development of aneurysms?
- AD Polycystic kidney disease
- Ehlers-Danlos syndrome type 4
- NF1
- Marfan syndrome
What is the most common location for:
- Saccular aneurysms
- Cavernomas
- Capillary telangiectasia
- Acomm
- Cerebellum then pons
- Pons
Which has intervening normal brain parenchyma?
Cavernomas
Capillary telangiectasia
Capillary telangiectasia
What are the most common bacterial organisms associated in:
- Infants
- Young adults
- Older adults
- Infants: E coli, Group B Streptococci
- Young adults: N meningitidis
- Older adults: S pneumoniae, L monocytogenes
The Waterhouse-Friderichsen syndrome results from meningitis-associated septicemia with hemorrhagic infarction
of the adrenal glands and cutaneous petechiae occurs most often with what organisms?
It occurs most often with meningococcal
and pneumococcal meningitis.
Chronic adhesive arachnoiditis most usually occurs after infection with what bacterial organism?
Pneumococcal meningitis
What bacterial organism has a basal distribution of exudates?
H. influenzae
Pneumococcal densest over the cerebral convexities
Which CSF parameter is usually normal in aseptic meningitis?
Sugar
What are the 2 characteristic findings in viral encephalitis?
- Perivascular cuffs of lymphocytes
2. Micrglial nodules– these nodules have multinucleated giant cells in HIV