Nervous System 2 Flashcards
Where are most CNS tumors found?
Intracranial tumors are most common (amongst those, supratentorial are most common); tumors of the spinal cord are much less common
True or false: CNS tumors are the second most common form of malignancy in children after leukemias.
True
Do primary CNS tumors often metastasize?
Nope; metastasis to the brain is much more common
What two types of tumors are the most common primary intracranial tumors in children?
Cerebellar astrocytoma and medulloblastoma
Name the three most common primary intracranial neoplasms in adults in descending order.
- Glioblastoma multiforme
- Meningioma
- Acoustic neuroma
Glioblastoma multiforme is a form of ______ and represents the highest grade ______. Its peak incidence is at the ages of…?
its a form of glioma and represents the highest grade astrocytoma
peak incidence is in late middle-ages
Glioblastoma multiforme most commonly originates in the _______ _______.
cerebral hemisphere
What is the prognosis for glioblastoma multiforme?
Very poor; death in
What microscopic morphological changes are seen in a glioblastoma multiforme (5)?
- Anaplasia
- Pleomorphism
- Hyperchromatism
- Vascular changes; endothelial hyperplasia
- Areas of necrosis and hemorrhage surrounded by a “PSEUDO-PALISADE” arrangement of tumor cells
What is a meningioma?
Benign, slow-growing tumor usually attached to the dura and arising around the meningothelial cells of the arachnoid.
Meningiomas most often occur after _____ years of age and is more frequent in ______ (males or females).
30 years old
more common in females
Where exactly in the brain are meningiomas often found?
In the convexities of the cerebral hemispheres and the parasaggital region
Describe the gross morphological appearance of a meningioma.
Well-defined, dural-based masses that compress the brain but can be easily separated from it.
Some meningiomas infiltrate the brain; this is associated with increased risk of ______.
recurrence
Describe the microscopic morphological changes seen in a meningioma.
Variable; WHORLED PATTERN of concentrically-arranged SPINDLE CELLS and laminated calcified PSAMMOMA BODIES
What is the prognosis of a meningioma dependent upon (3)?
- Size
- Location/surgical accessibility
- Histologic grade
Multiple sclerosis is a chronic primary disease of _______ characterized by a repalsing-remitting of the disease over many years.
chronic primary disease of myelin (white matter)
Which disease is the most common form of demyelinating disease? What is its prevalence?
multiple sclerosis (1 in 1,000 prevalence)
At what ages and in which gender does MS occur most often?
Most often begins between 20-30 years of age, 2X more common in women than men
What is the etiology of multiple sclerosis?
Unknown; multifocal - environmental, genetic factors result in loss of tolerance to myelin.
Risk of getting MS is ___-fold higher when the disease is present in a 1st degree relative, and there is also increased incidence in association with certain _____ haplotypes.
15-fold higher risk if 1st degree relative has it. Increased incidence in peeps with certain HLA haplotypes
What morphological changes are seen in the case of MS (7)?
- Affects white matter
- Confined to CNS
- Depletion of myelin-producing oligodendrocytes
- Multiple focal areas of demyelination scattered throughout the CNS
- T cells (CD4+ and CD8+) and macrophages infiltrate the plaques
- Axons are preserved
- Reactive gliosis
Describe the clinical features of MS (6).
- Multiple episodes of relapse and remission (although recovery is not complete)
- Gradual, stepwise accumulation of neuro deficits
- Lower extremity weakness
- Visual and sensory disturbances
- Retrobulbar pain
- Loss of bladder control
What is often found in the CSF of a patient with MS? What other lab finding is characteristic of MS?
CSF shows mildly elevated protein level with increased proportion of gamma-globulin.
Other finding: oligoclonal bands in Ig representing Abs against a variety of targets
What does Luxol fast blue do? What disease is this useful in observing the effects of?
It stains myelin - useful in detecting MS
What is the most common cause of dementia in the elderly?
Alzheimer’s
Describe the pathogenesis of Alzheimer’s.
Begins subtly as impairment of higher intellectual function and alterations in mood and behavior. Loss of memory is the most frequent early sign. Memory loss and aphasia (trouble with speech) progress onwards.
What is the most frequent cause of death in Alzheimer’s patients?
Pneumonia or other infections
The majority of Alzheimer’s cases are ______, but a familial form is recognized, making up ___ to ___% of cases.
most cases are sporadic
familial makes up 5-10% of cases
Name the four genetic factors associated with Alzheimer’s.
- Apolipoprotein E: e4 allele increases risk and early onset, E2 allele is protective.
- Presenilin-1: mutations increase risk for early-onset.
- SORL1: associated with late onset.
- Trisomy: patients with Down syndrome experience extensive senile plaque formation and early onset AD because the gene for amyloid precursor protein (APP) is on chromosome 21.
Alzheimer’s is characterized by the formation of senile (neuritic) plaques and _______ _______.
neurofibrillary tangles
What is a senile (neuritic) plaque (seen in Alzheimer’s)?
A spherical aggregate of beta-amyloid up to several micrometers in diameter
Beta-amyloid is formed by altered/assymetrical _______ of the amyloid precursor protein (APP), which is a transmembrane protein on neurons and glia, resulting in a ________ beta-amyloid peptide that accumulates in the senile plaques.
altered/asymmetrical cleavage –> insoluble beta-amyloid peptide
Are neurofibrillary tangles specific to Alzheimer’s? How do they stain?
They are found in other degenerative diseases. They are basophilic and appear as fibrillary structures in the cytoplasm or nucleus.
What is a neurofibrillary tangle (seen in Alzheimer’s)?
Intracytoplasmic bundles of paired helical filaments in the cytoplasm of neurons that displace or encircle the nucleus. They are made of hyper-phosphorylated TAU proteins.
Name four morphologic changes seen in Alzheimer’s.
- Neurofibrillary tangles
- Neuritic plaques
- Granulovacuolar degeneration - intraneuronal cytoplasmic granule-containing vacuoles occurring within the pyramidal cells of the hippocampus.
- Amyloid angiopathy - amyloid deposits in and around vessels.
Describe a neuritic plaque as seen in Alzheimer’s.
Focal, spherical collections of dilated, silver-staining neuritic processes, often around a central beta-amyloid core. Microglial cells and reactive astrocytes are present at their periphery
What is peripheral neuropathy and what can cause it?
Its a general term to describe loss of normal sensory or motor peripheral nerve functions.
Causes include trauma, metabolic, toxic, immune-mediated, infectious, and congenital disorders.
What is Wallerian degeneration?
Degeneration of the axon distal to a site of transection, which is followed by regeneration.
What is primary axonal degeneration?
Injury to a neuron associated with the axon. The axon dies back from the distal end. Many causes (ischemia, toxic, etc.).
What is segmental demyelination?
Loss of the myelin sheath in peripheral nerves. Often immune-mediated or due to infectious neuropathy.
What is meningeal carcinomatosis?
Metastatic cancer (eg. small cell lung cancer, breast cancer, melanoma) that spreads to the leptomeninges (the pia and arachnoid mater) surrounding the brain and spinal cord.
What are the clinical symptoms of meningeal carcinomatosis?
Symptoms arise from involvement of the brain, cranial nerves, and spinal roots:
- Headaches
- Nausea/vomiting
- Memory loss
- Sensory abnormalities
What is the prognosis for meningeal carcinomatosis?
Incurable; difficult to treat. Poor prognosis
Name a morphological feature (microscopic) seen in meningeal carcinomatosis.
Cancer cells form gland-like patterns in the subarachnoid space.
If you can smell peanut butter better with one nostril, what does that mean?
You might have Alzheimer’s
The integrity of the _______ ______ is important in nerve regeneration and guidance.
myelin sheath
