Neuropath Flashcards
Hypoxic injury
Loss of ribonucleoproteins and desaturation of cytoskeletal proteins leads to cytoplasmic eosinophilia and nuclear pykknosis
Red neurons
Neuron shrinks and becomes eosinophilia
Astrocytes responds to
Injury by proliferation of cytoplasmic process and intermediate filaments
Reactive gliosis by astrocytes
Analogous to fibrous scar
Oligodendrocytes injury results in
Demyelinating disease (MS)
Microglia
Antigen presenting cell
Can sometimes appear as rod cells
Neuron response to injury
Shrinkage Cell Body
Nuclear and nuclei degeneration
Breaks down in blood brain barrier with acute injuries
Astrocytes response to injury
Primarily responsible for repair and scar formation
Rosenthal fibers
Rosenthal fibers
Thick eosinophilic protein aggregates seen in chronic gliosis
Microglia cells response to injury
Microglia nodules
Neuropnphagia (eating of neurons) at injured site
Ependymal Cell Response to injury
Certain pathogens cause extensive ependymal injury with viral inclusions
Cerebral Edema Etiology
1) Disrupted blood brain barrier; increased vascular permeability (vasogenic)
2) Increase in water content secondarily to glial or endothelial injury (cytotoxic)
Cerebral edema causes
Compressed ventricle
Brain shifting
Swollen gyro
Narrowed sulci
Cerebral Edema: Brain Swelling leads to
Brain swelling leads to increased intracranial pressure
Present as Severe headache vomiting papilledema (swelling of optic disc)
Brain herniation
Displacement of brain tissue from one intracranial compartment to another-may result from brain swelling, tumor
3 types of brain herniation
Subfalcine (cingulate)
transtentorial (uncinate)
Tonsillar (the worst)
Uncinate will compress
CN 3
Hydrocephalus
Accumulation of excess CSF within ventricular system
Expanded ventricles with increased crainial pressure
Hydrocephalus caused by
Decreased CSF resorption (CSF flow obstructed by: Tumor, hemorrhage or inflammation)
-Increased CSF production (tumors of choroid plexus)
Cerebrovascular Diseases Mechanism
“Stroke”
1) thrombus occluded vessels
2) Moving thrombus (embolus) occluded vessels
3) Rupture of blood vessel
Stroke
Acute non epileptic neurological deficit lasting > 24 hours
Strokes result from 2 major processes
Occlusion/hypoxia
Hemorrhage
Brain hemorrhages
Intra-parenchymal hemorrhage
Subarachnoid hemorrhage
Vascular malformations
Most frequently affected with brain infarction
Middle cerebral artery
Brain infection risk factors
Hypertension, smoking, diabetes
Atherosclerosis is the most common underlying cause
Acute infarction
24-36 hours
Neurons become eosinophils
Neutrophils infiltrate into brain parenchyma
Subacute infarction
3rd-5th day
Involved tissue becomes softer in consistency
Macrophages with foamy cytoplasm begin to infiltrate
Chronic infarction
Weeks to months
Softening and liquefaction results in smooth walled cystic cavity
Loss of brain tissue
Intraparenchymal hemorrhage
Basal ganglia most commonly affected
Pons thalamus and cerebellum also affected
Subarachnoid hemorrage
Severe headaches
Rupture saccular berry anyersms
Most arise at artisan bifurcations of the circle of Willis
Vascular malformations hemorrhage
Arteriovenous malformation most common
Collection of abnormal blood vessel
Sucharachnoid or parenchyma hemorrhage results in neurologic deficits
Epidural hematoma
Rupture of a meningeal artery-arterial bleeding
Lucid interval
In epidural hematoma blood between
Skull and dura mater
Subdural hematoma blood between
Dura and arachnoid membrane
subdural hematoma disruption of
Bridging veins-Venous bleeding
Acute- Whiplash shake a baby
Chronic-elderly with brain atrophy
Concussion
Loss of consciousness with full recovery
Contusion
Disruption and hemorrhage of superficial brain caused by blunt trauma
Laceration
Tearing of brain parenchyma
Coup lesion
Impact site that hits the bone in contusion
Contrecoup
Contusion that develops on site opposite front he point of impact
Route of infection into CNS
1) Hematogenous spread
2) Extension of local infection
3) Direct implantation
4) Via peripheral nerves
Acute bacterial meningitis
Inflammation of leptomeninges and subarachnoid space
Cerebral abscess
Focal suppurative infection
Encephalitis
Diffuse inflammation of brain parenchyma; infections usually viral
Inflammation of leptomeninges spread through
Subarachnoid space
Acute bacterial meningitis caused by
Pyogenic bacteria
Acute bacterial meningitis risk factors
Extreme age
Debilitated state
Poor hygiene
Crowded living conditions
Acute bacterial meningitis the brain is swollen with
Purulent exudate under subarachnoid space over cerebral hemisphere and purulence within the ventricles
Brain Abscess
Usually bacteria or fungal
Brain abscess cavity contains
Pus surrounded by a thick wall of granulation tissue and fibrosis
Tuberculous Meningitis (Chronic) will present as
> 2-3 weeks of headache, lethargy, nausea, and vomiting
Tuberculous Meningitis (Chronic) exudate
Will be gelatinous and may appear Nodular
Cryptococcal Meningitis
Spherical budding yeast, found in soil and bird excrement
Cryptococcal Meningitis will present
With low grade fever, debility, headache
Cryptococcal Meningitis mostly seen
In both healthy and HIV patients
Cryptococcal Meningitis exudate
Slimy exudate capsular material
Encephalitis
Diffuse inflammation of brain parenchyma
Encephalitis infection is
Viral in origin
Hepesviruses-most common
Viral encephalitis untreated is usually
Fatal
Viral inclusion bodies
Within nucleus of infected neuron
Protein aggreagate of herpes virus
Encephalitis: perivascular lympocytosis
Lymphocytes collected around blood vessel
Neuronophagia and microglia nodules found in
Encephalitis
Multiple Sclerosis
Most common primary demyelinating disorder
MS caused by
Autoimmune (T Cell mediated) plus genetics
MS usually afffects
Young adults females
Irregular areas of demyelination
MS plaques
Alzheimer’s familal
10%
Alzheimer’s microscopically
Senile plaque of amyloid despoists
Neurofibrially tangles - filamenotous aggregates within neuronal cytoplasm
Parkinson’s is a degeneration of
Dopamine-secreting pigmented neurons of substantia nigra in the midbrain
Parkinson’s symtopms
Rigidity Expressionless face Stooped Posture Fine tremor Slower gait
Lewy bodies
Intracytoplasmic eosinophlic inclusions known as Lewy bodies within pigmented neurons
Huntington’s Disease grossly
Atrophy of the basal ganglia
Huntington’s Disease type
AD
Gene located in chromosome 4
Huntington’s Disease will present with
Spontaneous involuntary movements and dementia
Huntington’s Disease
Hereditary, progressively fatal disorder
Primary neural tumor arise from
Cells of the brain spinal cord or their coverings
Neural tumors _____ is more important than ______
Location
Type
Neural tumors rarely
Metastasize outside the CNS
Secondary nervous system tumors
Lung
Breast
Prostate
-Mets to brain: far more common than Mets FROM the brain
Most common Adult Brain tumors
Astrocytomas
WHO grades
II well differentiated
III anaplastic
IV glioblastoma
Astrocytoma Grade II
Mild cellualrity and nuclear pleomorphism
Astrocytoma Grade III
Highly cellular with mitosis figures
Grade IV glioblastoma
Necrosis and microvascular proliferation
Oligodendroglioma
Cerebral hemisphere, well circumscribed often calcified
Oligodendroglioma Cells with
Uniform round nuclei and perinuclear halo
Ependymoma lesions are
Well circumscribed lesions arising from ventricular wall
Ependymoma cells are
Elongated with processes radiating around blood vessels
Meningioma derived from
Arachnoid matter
Meningioma predominance
Female
Meningioma lesions will be
Firm lobulated lesions with a pushing border into underlying brain
Psammoma bodies
Calcification
Meningioma microscopically
Cellular whorls
Psammoma bodies
Pediatric brain tumors
Pilocytic astrocytoma
Pilocytic Astorcytoma
Grade I tumor
Usually in the cerebellum, often cystic
PA: Rosenthal fibers
Astrocytes with hair like processes
Medulloblastoma
Cerebellum, aggressive growth pattern
Grade IV tumor
Medulloblastoma Cells disseminate through
CSF