CNS pathology-1 Flashcards
What is the most common location of a hypertensive bleed?
The Basal Ganglia- Thalamus (75%)
What causes a Berry Aneurysm?
- Congenital arterial defects that occur when the bifurcation of an artery creates a “Y-shape”, creating a point of weakness
- Continuous pressure on the point of bifurcation causes membrane to degenerate and fragment
- A saccular aneurys evolves, walls are only adventitia
Where are most Berry aneurysms?
over 90% occur at branching points in the Circle of Willis
Berry aneurysms are distributed equally at the unions of…
- Anterior cerebral artery and anterior communicating artery
- Complex of the internal carotid artery- posterior communicating artery-anterior cerebral artery
- The trifurcation of the middle cerebral artery
20% have multiple berrys
What does a ruptured Berry Aneurysm result in?
- life threatening subarachnoid hemorrhage
- Initial hemorrhage= 35-50% mortality
Berry aneurysms- what do large aneurysms of the internal carotid complex produce?
- Palsies of the 3rd, 4th and 6th cranial nerves
- Seizures from compression of temporal lobe
Clinical presentation of Berry Aneurysms
- many asymptomatic (only found at autopsy)
- Sudden severe HA due to SAH and can be followed by coma
- If pt survives 3-4 days: progressive decline in consciousness (from arterial spasm leading to cerebral ischemia and infarction)
What happens in 1/3 of patients with a ruptured Berry Aneurysm?
Rupture can either cause an intracerebral or intraventricular hemorrhage
What are the two most common organisms that cause neonatal meningitis?
- Group B Strept
- E.coli
What is the most common organism causing bacterial meningitis in infants (3 months-3 years)?
H. influenza
What is the most common origanism that causes bacterial meningitis in adults not in crowded conditions?
Strep pneumo
What is the most common organism that causes bacterial meningitis in people in crowded conditions (military barracks)?
N. meningitidis
How is Parkinson Disease characterized pathologically?
A neurologic disorder characterized pathologically by the loss of neurons in the Substantia Nigra
How is Parkinson Disease characterized clinically?
- Tremors at rest
- Muscular rigidity (Cog wheel rigidity) throughout entire ROM
- Expressionless face (“mask”)–> expression fixed, eyes unblinking and staring, mouth open
- emotional lability
- slowness of all voluntary movements
- Course tremor of distal extremities (“pill-rolling”)- present at rest, disappears w/ voluntary movement
- Drooling
- spontaneous movement diminished (akinesia)
- Posture is stooped
When does Parkinson Disease typically appear?
In the 6th decade to 8th decades of life
What neurotransmitters are deficient in Parkinson Disease?
Dopamine!
Parkinsons= Accelerated loss of neurons in the Substantia Nigra and reduction in the dopamine content of that region
Note: Substantia Nigra relays info to basal ganglia through dopaminergic synapses
What group of brain tumors is the most common type of brain tumor?
Gliomas (tumors of neuroectodermal origins)
=60% of primary intracranial neuoplasms
What does gross examination of a brain with Parkinson disease reveal?
A loss of pigmentation in the Substantia Nigra and Locus Ceruleus
What area of the brain is Parkinson disease
Substantia Nigra (in the midbrain) and Locus Ceruleus (a nucleus in the pons of the brainstem)
What is there an increased incidence of in people with Parkinson disease?
Depression
Dementia
What brain tumor accounts for 75-80% of adult primary brain tumors?
Astrocytomas
What is alzheimers disease?
an insidious and progressive neurological disorder characterized by loss of memory, cognitive impairment and eventual dementia
Gross features seen in Alzheimers
- narrow gyri
- Sulci widen
- Bilateral cortical atrophy
–>All 3 are apparent in the frontal, temporal, parietal and hippocampal cortices (spares the occipital lobes)
Microscopic features seen in Alzheimers
- Senile (neuritic) plaques- found predominantly in hippocampus, amygdala and cortex
- Neurofibrillary Tangles (Flame cells seen on histology)- found in cortex, hipocampus and amygdala
- Amyloid angiopathy (within cerebral blood vessels)
What are the most common tumors that metastasize to the brain?
Disseminated Melanoma (50% of metastasis)
Breast and lung (35%)
Kidney and colon (5%)
**Prostate, liver and sarcomas rarely spread
How do metastatic tumors reach the brain
through the bloodstream
What brain tumor accounts for 20% of brain tumors in children?
Ex: Neuroblastoma, Retinoblastoma, etc
Medulloblastoma
Where are Medulloblastomas located?
infiltrates the vermis of the Cerebellum
frequently disseminates through the CSF
What is the most common genetic alteration associated with Medulloblastoma?
loss of material from short arm of chromosome 17
Medulloblastoma- radiosensitivity
Tumor is highly malignant but also extremely radiosensitive if diagnosed early enough
With total excision and radiation- 10 yr survival rate is 50%
