Path: CNS Flashcards
Disruption of the ependymal lining and prolferation of subependymal astrocytes produces what on ventricular surfaces?
Ependymal granulation
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
A patient presents after a direct blow to the head which initially knocked him unconscious, after a couple hour lucid interval he begins to exhibit neurological deterioration, what do you suspect?
Epidural hematoma
Small slit like cavity that is surrounded by a brownish discoloration after reabsorption of a hemorrhage is known as what?
Slit hemorrhage
What is a Charcot-Bouchard microaneurysm vs. Saccular (berry) aneurysm?
Where is each most commonly seen?
- Charcot-Bouchard occur in vessels less than 300 um in diameter; most often within basal ganglia
- Saccular (berry) aneurysms occur in larger intracranial vessesl in the subarachnoid space
Which cell type is evident 12-24 hrs after acute CNS hypoxic/ischemic insult?
Red neurons (“red dead guys”)
Which intracranial location is most susceptible to a direct parenchymal injury which results from trauma to the head?
Crests of the gyri = greatest amt. of force
Periventricular heterotopias can be caused by mutations in the gene encoding?
Filamin A, an actin-binding protein
What type of edema is associated with brain abscesses?
- Vasogenic edema
- Newly formed vessels that are very leaky
What are the clinical manifestations of Creutzfeldt-Jakob Disease (CJD)?
Subtle changes in memory/behavior followed by a rapidly progessing dementia, often associated with pronounced involuntary jerking muscle contractions on sudden stimulation (startle myoclonus)
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
Cerebral Autosomal Dominant Arteriopathy w/ Subcortical Infarcts and Leukoencephalopathy (CADASIL) is characterized clinically how?
Recurrent strokes (usually infarcts, less often hemorrhages) and dementia
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 symptoms would result from Subfalcine herniation with compression of the ACA?
Contralateral lower extremity weakness
Morphology of Arteriorvenous Malformations
Tangled vessels (“worm-like”) that show prominent, pulsatile arteriovenous shunting with high blood flow – bypass a capillary bed
What is Binswanger disease?
Pattern of injury from multifocal vascular diseases involving large areas of subcortical white matter w/ myelin and axon loss
How can HTN lead to the development of lacunar infarcts?
Cerebral vessesl develop arteriolar sclerosis and may become occluded —> Lacunes
Radiologic imaging showing a “bat wing” deformity is associated with that condition?
Agenesis of the corpus callosum
If the head is immobile at the time of trauma, what time of injury will be found?
Only a coup injury
What is the most common parasitic nervous system disease in the world and can lead to hydrocephalus?
- Cysticercosis
- Taenia Solium (pork tapeworm)
What is seen during the acute phase of HIV infection of the CNS?
Mild lymphocytic meningitis, perivascular inflammation, and some myelin loss
Why is it crucial to exam the eyes of a patient you expect to be suffering from increased intracranial pressure?
Look for papilledema
__________ act as the metabolic buffers and detoxify the brain; also contributing to the BBB (foot processes)
Astrocytes
What is seen in the brains of individuals with CTE (dementia pugilistica) during a post-mortem autopsy?
- Atrophic w/ enlarged ventricles
- Accumulation of tau-containing neurofibrillary tangles
- Characteristic pattern involving superficial frontal and temporal lobe cortex
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 are the only CNS cell type to express both the CD4 coreceptor and the chemokine receptors (CCR5 or CXCR4) that are required in combination for efficient infection by HIV?
Microglia
Morphology of red neurons
- Shrinkage of cell body
- Pyknosis of nucleus
- Dissapearance of nucleolus
- Loss of nissl substance
- Intense eosinophilia of the cytoplasm
Creutzfeldt-Jakob Disease (CJD) has a peak incidence during what decade?
How is it transmitted?
Average survival time?
- During the seventh decade
- Iatrogenic transmission, notably by corneal transplantation, deep implantation of electrodes in the brain, and administration of contaminated preparations of naturally derived GH
- Average survival = 7 months
Most important histopathologic indicator of CNS injury regardless of etiology?
Characterized by what 2 things; what cell?
- Gliosis
- BOTH hypertrophy and hyperplasia of astrocytes
Extensive ischemic damage of both white and gray matter leading to large cystic lesions during the perinatal period is known as?
Risk factor for developing?
- Multicystic encephalopathy
- Cerebral Palsy
How does vCJD differ clinically from CJD?
- Behavioral changes early in the disease
- Slower progression of neurologic symptoms
A subfalcine herniation may lead to compression of the ________ artery leading to infarction
Anterior Cerebral artery (ACA)
______ are mesoderm derived phagocytic cells that serve as resident macrophages of the CNS
Microglia
Which artery is most frequently affected by embolic infarction?
MCA — direct extension of the internal carotid artery
Most common sites for thrombotic occlusions in the brain
- Carotid bifurcation
- Origin of MCA
- Either end of Basilar artery
What are characteristics of a gemistocytic astrocyte?
- Nucleus enlarges, become vesicular, and develop prominent nucleoli
- Bright pink cytoplasm, forms swaths around the eccentric nucleus that forms numerous stout ramifying processes
Negri bodies associated with rabies infection are found where in the brain?
- Pyramidal neurons of the hippocampus
- Purkinje cells of the cerebellum
*Sites usually devoid of inflammation
What is the mutation associated with Cerebral Autosomal Dominant Arteriopathy w/ Subcortical Infarcts and Leukoencephalopathy (CADASIL)?
NOTCH3
What is the response of astrocytes to neuronal injury?
- Hypertrophy of the cytoplasm, accumulation of GFAP, and hyperplasia
What is the risk factor most commonly associated with deep brain parenchymal hemorrhages?
HTN
What are congenital causes of hydrocephalus?
- Intrauterine infections (TORCH)
- Agenesis/atresia/stenosis
- Arnold chiari malformations
- Dandy walker syndrome
- Cranial defects: Achondroplasia and Craniostenosis
Dandy-Walker malformations have a large midline cyst that is lined by ______ and is continguos with _________ on its outer surface
Lined by ependyma and is contingous with leptomeninges on its outer surface
Cerebral malaria is a rapidly progressing encephalitis caused by what organism?
Plasmodium falciparum
Onset of the variant form of CJD is linked to consumption of?
Bovine spongiform encephalopathy agent in contaminated foods or blood transfusion
What is seen on electron microscopy with CJD and vCJD?
How are they stained?
- Kuru plaques: extracellular deposits of aggregated abnormal protein (will have halo of spongiform in vCJD); usually seen in the cerebellum, but are abundant in the cerebral cortex in cases of vCJD
- Congo red and PAS-positive
Sudden onset of severe headache (“worst headache of my life”), often with rapid neurologic deterioration is consistent with a _________ hemorrhage
Subarachnoid
The cause of Microcephaly is linked to?
- Chromosomal abnormalities
- Fetal alcohol syndrome
- HIV-1 acquired in utero
What are the 3 main forms of injury to the CNS caused by fungal infections?
1) Chronic meningitis
2) Vasculitis
3) Parenchymal invasion
What are the subacute changes seen 24 hours to 2 weeks after global ischemia?
- Tissue necrosis
- Influx of Macrophages and Reactive gliosis (10 days)
- Vascular proliferation
How does CNS infection by poliovirus present initially and what are the CSF findings?
- Meningeal irritation
- CSF consistent w/ aseptic meningitis (pleocytosis of lymphocytes, moderately elevated protein, nearly normal glucose)
What causes Charcot-Bouchard microaneurysms?
Chronic HTN
What type of hematoma is associated with rupture of the bridging veins?
Subdural hematoma
What is the classic triad of clinical findings exhibited by patients with normal pressure hydrocephalus?
- “Wet, wacky, and wobbly”
- Often exhibit a magnetic gait
- Dementia-like sx’s; impaired recognition (often not severe)
- Urinary incontinence; appears late in illness and is generally of the spastic hyperreflexic, increased-urgency type
What is the risk factor most commonly associated with lobar hemorrhages?
Cerebral amyloid angiopathy (CAA)
Clinical term for altered consciousness secondry to a head injury typically brough about by a change in momentum of the head
Concussion
What does HSV-2 cause particularly in neonates born by vaginal delivery to a woman with active primary HSV genital infections?
Severe encephalitis
What are the neurologic symptoms associated w/ Neuroborreliosis (Lyme Disease)
- Aseptic meningitis
- Facial nerve palsies
- Encephalopathy
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
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
What type of cytoplasmic inclusion bodies are characteristic of Pilocytic Astrocytoma and also found in regions of long standing gliosis?
Rosenthal fibers
Glial cytoplasmic inclusions, primarily composed of ______ are found in oligodendrocytes in multiple system atrophy (MSA).
α-synuclein
The border zone between which arteries in the cerebral hemispheres are most at risk for an infarct following global ischemia?
Between ACA and the MCA
The presence of which alleles may increase the risk of repeat bleeding from sporadic CAA?
ε2 or ε4
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
What are the most commonly encountered fungi that invade the brain?
Candida and Cryptococcus
Holoprosencephaly is associated with what disease and signaling mutation?
- Trisomy 13
- Sonic hedgehog signaling pathway
Infarcts are often initially nonhemorrhagic, but secondary hemorrhage can occur from ______ injury
Ischemia-reperfusion
What is the structural abnormality of vessels that lead to saccular (berry) aneursyms?
Absence of smooth muscle and intimal elastic lamina = developmental disorder
What is Holoprosencephaly? Severe forms produce which abnormalities?
- Incomplete separation of the cerebral hemispheres across the midline
- Cyclopia; less severe variants (arrhinencephaly) show absence of olfactory CNs
What may be seen on CT with cerebral toxoplasmosis infection?
Ring enhancing lesions
What is the morphology of cerebral toxoplasmosis abscesses; most often seen where?
- Mostly affect the cerebral cortex (near the gray-white junction) and deep gray nuclei
- Central necrosis, petechial hemorrhage surrounded by acute and chronic inflammation, macrophage infiltration, and vascular proliferation
Vasculitis associated with fungal infections is most frequently seen with what organisms?
Mucormycosis and Aspergillosis
What is chemical meningitis?
Nonbacterial irritant introduced into the subarachnoid space
What is the most common site for Arteriovenous Malformations?
MCA; particularly its posterior branches
How does FFI differ from the other prion diseases, morphologically?
Does not show spongiform pathology
What is diffuse vs. focal mass effect that is associated with herniation?
- Diffuse: generalzied brain edema
- Focal: tumors, abscesses, or hemorrhages
Which encephalitis is characterized by patches of irregular, ill-defined white matter injury w/ enlarged oligodendrocyte nuclei containing glassy amphopilic viral inclusions?
Progressive Multifocal Leukoencephalopathy (PML)