Pathology - CNS Flashcards
Lipofuscin
Accumulation of complex lipids due to age in neurons cytoplasm and lysosomes
Gliosis and who does it?
Repair and scar formation in the CNS carried out by astrocytes
Ependyma cells
They line the ventricles
Choroid plexus
They produce CSF fluid
Cerebral edema
Excess fluid in brain parenchyma
Vasogenic edema
occurs when the BBB is disrupted so liquid goes from vascular part to extracellular parts
Cytotoxic edema
increase in intracellular fluid due to neuron or glial cell membrane damage:
Foramena Magendie and Luschka
Opening from the 4th ventricle to the subarachnoid
hydrocephalus
Accumulation of excess CSF within the ventricle system
non-communicating hydrocephalus
blockage in ventricular system flow by masses mainly in foramen Monroe or compressing the cerebral aqueduct
Communicating hydrocephalus
All the ventricles enlarged and caused by the reduced resorption
Hydrocephalus ex vacuo
Enlarged ventricles because of atrophy of brain parenchyme
Subfalcine herniation ( cingulate)
unilateral expansion of a cerebral hemisphere displaces the cingulate gyrus under the falx. This compresses the anterior cerebral artery
Transtentorial (uncinate) herniation
Medial aspect of temporal lobe is compressed against the tentorium. CN III is compressed. Posterior cerebral artery may be compressed also affecting the primary visual cortex
Kernohan’s notch
Compression of the peduncle against the tentorium causing hemiparesis ipsilateral to the side of herniation
Duret’s hemorrhages
Transtentorial (uncinate) herniation accompanied by linear or flame shaped hemorrhages in the midbrain or pons
Tonsillar herniation
displacement of the cerebral tonsils through the foramen magnum.
Which herniation is life threatening
Tonsillar herniation because it causes brain stem compression and compromises respiratory and cardiac centers in the medulla
Functional Ischemia
low partial pressure of oxygen e.g high altitude impairing oxygen carrying capacity
Ischemia
due to tissue hypoperfusion can be permanent or transient
Global Cerebral Ischemia
widespread ischemic hypoxia if pressure is below 50mmHg like in cardiac arrest, shock or hypotension
Most susceptible cells in the brain to hypoxia
Neurons
Most susceptible neurons
Pyramidal cells of hippocampus and neocortex and Purkinje cells of the cerebellum
Respirator brain
Irreversible brain damage thats now on mechanical ventilation and brainn undergoing autolysis
Histological changes in irreversible injury is in 3 categories
Early changes, Subacute changes and Repair
Early changes of irreversible injury
12-24hours. Red neurons, microvacuolization, cytoplasmic eosinophilia, nuclear pykosis and karyorrhexis. Also occurs in astrocytes and oligodendrocytes later
Subacute changes of irreversible injury
24hours-2weeks. Tissue necrosis, macrophages, vascular proliferation and reactive gliosis
Repair
> 2weeks. Removal of necrotic tisssue, loss of CNS structure, and gliosis
Border zone( Watershed infarcts)
wedge shaped areas that lie at the distal end of blood supply
What zone is at greatest risk for hypotensive episodes in the cerebral hemispheres
Zone between the anterior and middle cerebral artery
Focal Cerebral Ischemia
This is the first stage of cerebral artery occlusion.
Which structures have no collateral blood flow
thalamus, basal ganglia and deep white matter
Embolic or thrombosis infarction more common
Embolic
Factors for cardiac mural thrombi
MI, Valve disease, Atrial fibrillation
Most common cerebral artery affected by embolic infarction
middle cerebral artery
Superimposed thrombotic occlusions on atherosclerosis places in the cerebral
Carotid bifurcation, origin of middle cerebral artery and basilar artery
Non hemorrhagic infarcts
acute occlusion that can be treated with thrombolytic
Hemorrhagic infarcts
reperfusion of infarcted tissue producing petechial hemorrhages
Non contributors to the healing process of infarction
Pia and arachnoid
Most common cause of subarachnoid hemorrhage
Ruptured aneurysms from HTN
Sites of HTN intraparenchymal hemorrhages
Basal ganglia, thalamus, pons, cerebellum
Cerebral Amyloid Angiopathy
amyloid peptides depositing in meningeals and cortical vessels. It stains with Congo Red. Weakens vessel to cause hemorrhages
Location of Cerebral amyloid angiopathy
CErebral cortex ( lobar hemorrhages)
Most common cause of non-traumatic subarachnoid hemorrhage
saccular (berry) aneurysm
The worst headache I have ever felt and becomes unconscious
Subarachnoid hemorrhage
Location of most saccular aneurysms
Anterior circulation
Who had increased risks for aneurysms
ADPKD
What layers are present in aneurysm
Hyalinized intima
Most common location for a atherosclerotic aneurysms
basilar artery involvement
Vascular malformations
Arteriovenous malformations, Cavernous malformations, Capillary telangiectasia, Venous angiomas
Whats the most common vascular malformations
Arteriovenous malformation
Arteriovenous malformations presentation
10-30, seizures, intracranial or subarachnoid hemorrhage
What genetic defect is seen in most multiple Arteriovenous malformations
Herediatary hemorrhagic telangiectasia
Cavernous malformation occurences
Cerebellum, pons and subcortical regions
Capillary telangiectasis
Pons (no bleed)
Venous angiomas
venous channels
Lacunar infarcts
small infarcts due to occlusion of a single penetrating branch of a large cerebral artery occurring in the deep gray matter- basal ganglia, thalamus, internal capsule, deep white matter and pons
Acute HTN encephalopathy
when diastolic pressure is >130mmHg
Causes of Primary angiitis of the CNS
chronic inflammmation, giant cells and destruction of vessel walls
Coup injury
Injury occurring at the site of of head impact
Contrecoup injury
Injury to the opposite side of where the head was hit
Contusion
Rapid tissue displacement, disruption of vascular channels and then hemorrhage, tissue injury and edema
What brain part most susceptible to traumatic brain injury
Crest of gyri
Concussion
Reversible altered consciousness from head injury without contusion
Epidural Hematoma
Middle meningeal artery from skull fractures
Subdural Hematoma
Rapid movement of brain during trauma can tear the bridging veins spilling into the subdural space. Higher rates in older people because bridging veins strethced out and children because theirs is thin-walled
Most common site for a subdural hemorrhage
Lateral aspects of the cerebral hemisphere and can be bilateral
Most frequent type of CNS malformation
Neural tube defect at the posterior end, where spinal cord forms
Anencephaly
malformation of anterior end of neural tube, leads to absence of brain and top of skull
Encephalocele
Diverticulum of malformed CNS tissue extending through the cranium defect
Microencephaly more common than macro. Causes
fetal alcohol syndrome, HIV acquired in utero, chromosome issues
Lissencephaly ( agyria)
Absent gyration leading to smooth brain surface
Holoprosencephaly
disruption of normal midline dividing due to sonic hedgehog mutations
Arnold Chiari malformation Type II
small posterior fossa with mishapen midline cerebellum with vermis through foramen magnum, hydrocephalus and lumbar myelomeningocele
Dandy Walker malformations
Enlarged posterior fossa, non-cerebellar vermis, large midline cysts and Joubert syndrome
Joubert syndrome
No vermis so eye movement problems
Cerebral palsy
Non-progressive neurological motor deficits featuring spasticity, dystonia, ataxia or athetosisand paresis
Most common injuries that occur in perinatal periods are
hemorrhages and infarcts
Routs of reaching Nervous System by microbes and most common one
hematogenous( most common), direct, local extension( air sinuses), peripheral nerves
Meningitis
Inflammation of the leptomeninges within the subarachnoid space
Acute Pyogenic Meningitis ( Bacterial Meningitis)
Neonates: E.coli, Group B Strep,
Adolescents and Young Adults: N. meningitis, (most common),
Older: Strep pneumococcus and Listeria mening
Signs of Meningitis
Headache, photophobia, irritability, clouded consciousness and neck stiffness
Aseptic meningitis ( viral meningitis)
Self limiting, lymphocytes, normal glucose levels,
Features of TB chronic meningitis
lymphocytes, plasma cells and macrophages
Location of Neurosyphilis
Base of brain
Aseptic meningitis with facial palsy, polyneuropathies
Lyme disease by Borrelia burgdorferi
Increased intracranial pressures with progressive focal deficits
Brain abscess
Viral spread range in brain abscess
Diffuse
Bacterial spread range in brain abscess
Localized
Abscess
Discrete lesion with central liquified necrosis surrounded by a fibrous capsule
How does center of abscess look like
Granulomatous tissue with exuberant vascularization and a zone of reactive gliosis
Meningoencephalitis
Viral encephalitis
Alterations in mood, memory and behavior
Herpes virus in the CSF
HIV encephalitis H&E slide feature
multinucleated giant cell due to infecting microglial cells causing an innate immune response
Loss of motor neurons and paralysis of respiratory muscles
Polio virus
Headache, malaise, fever, slight touch is painful sensation, and convulsions to mania and stupor progressing to coma
Rabies from a bat
Oligodendrocyte demyelination in immunocompromised person, focal and progessive neurological symptoms, ring forming lesions in the hemisphere
Progressive multifocal leukoencephalopathy (PML) caused by JC virus a polyomavirus
Triad of chorioretinitis, hydrocephalus and intracranial calcifications
Toxoplasmosis
Meningitis in immunocompromised person,”soap bubble appearance” and India Ink is used
Cryptococcus neoformans
Cysticercosis in the brain and subarachnoid space, causing seizures
Tenia solium
Rapidly fatal necrotizing encephalitis from swimming in nonflowing warm freshwater
Naegleria spp
Chronic granulomatous meningoencephalitis
Amoeba
> 70 years old, Rapidly progressing dementia illness
Spongioform transformation of cerebral cortex and deep gray matter
Creutzfeldt-Jakob disease
Young adultsSlowly progressive dementia, spongioform encephalitis ( cattle), abundant cortical amyoid plaques
Variant-CJD
Distinct episodes of neurological deficits, separated in time and space, oligoclonal bands seen in brain
MS
MS players
CD4, Th 17, Th1, CD8, B cells, IL-2, IL-7
Acute disseminated encephalomyelitis
Develop a week or 2 after infection, headache, lethargy and coma. Non localizing findings
Acute necrotizing hemorrhagic encephalitis
similar to MS but affecting young adults and children
Neuromyelitis optica
Inflammatory demyelinating disease of the eyes and spinal cord
Diagnostic text for Neuromyelitis optica
Antibody to aquaporin 4
Central Pontine Myelinolysis
Non-immune loss of myelin involving the pons after a rapid correction of hyponatremia causing rapidly evolving quadriplegia
Arylsulfatase A deficiency
Metachromatic leukodystrophy
Galactocerebroside beta galactosidase deficiency
Krabbe disease
Peroxisome dects: elevated very long fatty acid chains
Adrenoleukodystrophy
Aspartoacylase deficiency
Canavan disease
Proteolipid protein mutation
Pelizaeus-Merzbacher dx
Translation initiation factor
Vanishing white matter
GFAP mutations - Glial fibrillary acidic protein
Alexander dx
Abrupt onset of confusion, abnormal eye movements, ataxia. Mammaory body necrosis with preservation of the neurons
Wernicke-Korsakoff syndrome in alcoholics due to thiamine deficiency
What brain structure mostly affected by hypoglycemia
hippocampus neurons
Why hyperglycemia bad
Intracellular dehydration, onfusion, stupor and death
Elevated ammonia, Flapping tremor, inflammation and hyponatremia
Hepatic encephalopathy
Protein inclusion and location in Alzheimer
Abeta and tau. Extracellular neurons
Protein inclusion and location in Frontotemporal lobar degeneration
Tau, TDP-43. Neurons
Protein inclusion and location in Progressive Supranuclear palsy and Corticobasal degeneration
Tau. Glial and neurons
Protein inclusion and location in Parkinsons
alpha-synuclein and neurons
Protein inclusion and location in Multiple System Atrophy
alpha-synuclein and neurons and glial
Protein inclusion and location in Amyotrophic lateral sclerosis
TDP-43, SOD-1 and neurons
Protein inclusion and location in Huntington Disease
Huntingtin and neurons
Spinocerebellar ataxias
Ataxins and neurons
Elderly, > 65 loss or memory, altered mood and behavior,, disorientation and memory loss and aphasia. In 5 to 10years becomes mute and immobile
Alzheimer disease. Abeta plaque accumulation causes the chain of events.
Risk factors for Alzheimer disease
Downs syndrome (Trisomy 21), ApoE4, Abeta plaques cause inflammation causing cell injury and hyperphosphorylation of Tau which then forms tangles
What forms tangles in Alzheimer disease
Taus that were overphosphorylated by Abeta plaques. Taus cause neural dysfunction and death
Diagnosis of Alzheimer
Plaques with neurofibrillary tangles
Frontotemporal Lobar degeneration difference from Alzheimer
Behavior changes/language defects precedes memory ( dementia) deficits.
Mutations in Frontotemporal Lobar degeneration
Smooth round inclusions9Pick bodies)-Picks disease
Aggregates of DNA/RNA binding -TDP-43 ( frontal lobe impairment)
Tremor, Rigidity, bradykinesia and instability
Parkinsons
Cause of Parkinsons
Damage to dopaminergic neurons from the substantia nigra to the striatum
Diagnostic of Parkinsons
Lewy bodies- an inclusion containing alpha-synuclein
Diseases with alpha-synuclein
Parkinson, Multiple System atrophy, Progressive supranuclear palsy, and corticobasal degenration
Lewy body dementia
Dementia with hallucinationsarising within one year of motor symptoms
Degeneration of the striatum- caudate and putamen, choreiform-dancelike, increased voluntary jerky movements. Progressive disease and death after 15 years
Hungtinton
Cause of Huntington
CAG trinucleotide repeat expansions on Ch 4. Anticipation involved, Atrophy of caudate nucleus,
Friedreich Ataxia
GAA repeat in gene for frataxin, leads to mitochondrial dysfunction and increased oxidative damage
Features of Friedreich Ataxia
<10. Gait ataxia, Hand clumsiness, dysarthria, pes cavus, kyphoscoliosis, cardiac disease and diabetes
Amyotrophic Lateral Sclerosis
Loss of upper and lower motor neurons. with hyperreflexia, babinski sign
Cause of Amyotrophic Lateral Sclerosis
SOD-1 on Ch 21 mutation, DNA/RNA binding protein, TDP-43
Most CNS tumor location in children
Posterior fossa
Most CNS tumor location in adults
Supratentorial
Gliomas are
astrocytomas, oligodendrogliomas and ependymomas
Diffuse gliomas
astrocytomas, oligodendrogliomas and mixed
Solid masses glioma
Ependymomas
40s - 60s, seizures, headaches and focal neurological deficits
Diffuse astrocytoma
Diagnosis of Diffuse astrocytoma
GFAP +, IDH1
Child, young adult, tumor in cerebellum, 3rd ventricle involvement, Rosenthal fibers with eosinophil granular bodies
Pilocytic Astrocytoma
Mutations in Pilocytic Astrocytoma
serine-threonine kinase BRAF, V600E, IDH1
Frontal or temporal lobe masses, focal hemorrhage, calcifications round nuclei surrounded by white halo
oligodendrogliomas
Cause of oligodendrogliomas
deletion of 1p, 19q, responsive to chemotherapy and radiotherapy
Tumor arising by ventricular system,
Ependydoma
Most common location of Ependydoma in adults
Spinal cord
Most common location of Ependydoma in first 2 decades
Near the 4th ventricle
NF2 associated with what tumor
Ependydoma
Features of Ependydoma
Rosette canals
Most common primitive neuroectodermal tumor (PNET)
Medulloblastoma
Location of medulloblastoma tumor in child
midline
Location of medulloblastoma tumor in adult
Lateral tumor
Which medulloblastoma have good outcomes
WNT
Which medulloblastoma have good outcomes
MYC
Most Common Primary CNS tumor in immunocompromised
Diffuse large B cell lymphoma with Epstein Barr virus
Most common primary CNS germ cell tumor
germinoma
Multiple meningiomas with 8th nerve schwannomas or glial tumors think
NF2 on ch 22
Features of meningiomas
Psammoma bodies, synctial whorled clusters of cells like keratin
Most common primary sites of metastatic tumors
Lung, breast, skin, kidney and GI
Benign neoplasms, hamartomas in brain
Tuberous sclerosis
Associations with Tuberous Sclerosis
renal angiomyolipomas, retinal glial hamartomas, pulmonary lymphangiomyomatosis and cardiac rhabdomyomas
Tuberous sclerosis
a normal tissue growing at the same rate as neighbors but growing in an irregular pattern
von Hippel-Lindau disease association
Hemangioblastomas within the cerebellar hemispheres, retina. Renal cell carcinoma
Role of VHL genes
Encodes protein thats part of ubiquitin ligase complex. that targets hypoxia induced factor for degradation. Mutation causes high HIF which causes VEGF, growth factors, erythropoietin to form paraneoplastic polycythemia
Role of HIF
causes VEGF, growth factors, erythropoietin to form paraneoplastic polycythemia
Most often nerve affected with Schwannomas
CN VIII
Bilateral vestibular schwannomas
NF2 with loss of function on Ch 22
NF2 mutation at risk for
Schwannomas, Meningiomas and ependydomas
NF1 origin
Ch 17, regulator of Ras
NF2 origin and role
Ch 22 and its Merlin gene is a tumor suppressor of E-cadherin mediated contact inhibition
Features of NF1 mutation
learning disability, seizures, skeletal deformities, arterial stenosis, pigmented iris, pigmented skin lesions (axillary freckling and cafe au lait spots)