Introduction to Neuropathology Flashcards
Name the three features of the evolving human brain that helped shape women’s sexual and reproductive health during evolution.
- Increased need for energy and nutrients during fetal development
- Relatively large size of brain and fetal head
- Need for a long time to complete its development after birth
Why is the human placenta so invasive?
Due to growing fetal needs and the requirements of the developing human brain (during week 16 of pregnancy)
What are the two molecules that the brain needs to function properly or else it will be damaged?
- Glucose
2. Oxygen
What is the brain composed of?
Lipids (i.e. sphingomyelin and cerebrosides)
What is the functional unit of the nervous system?
Neuron
How many neurons are there in the human brain?
Standard says 100 Billion neurons (but some one did a research study on it and measured it out to be around 86 Billion)
Glial cells are derived from which germ layer?
Neuroectoderm
What are the three glial cells?
- Astrocytes
- Ependymal Cells
- Oligodendrocytes
How many glial cells are there in the nervous system?
They say a safe estimate is 10x the amount of neurons
What is the most abundant glial cell?
Astrocytes
If you perform a glial stain on cell in the brain, which cell will not light up? Why?
Microglia!
They will not light up because they are derived from Monocytes which are NOT from the neuroectoderm in origin (more like mesodermal origin)
What is the neurophil? What can it tell us?
Surrounding tissue that is not made up of the glial cells, microglia, neurons or blood vessels.
It can tell us that something bad is happening with the brain (i.e. Hypertrophy and Hyperplasia of Astrocytes)
What is the relationship between Grey and White matter?
Which cells are found in these areas?
Grey is outside of white
Grey = Neocortex
White = Glial cells
How many layers are in the neocortex?
What is the organization of these layers?
6
I is the outermost with VI being the innermost
Describe the organization of the Cerebellar Cortex (from outside to inside).
Which cells are specific to the cerebellum?
Molecular Layer - Granular Layer - White Matter
Pirkinje Cells
Red neurons, spheroid and central chromatolysis are all examples of ________ .
Acute Neuronal Injury (within 12 hrs of irreversible hypoxia/ischemia)
Lewy bodies, lipofuchsin and dystrophic neurites are all examples of _________ .
Intracellular inclusions
What can viral infections (in general) cause in the brain?
Intranuclear Inclusions
Intracytoplasmic Inclusions
Both
What is the space called that is an extension of the subarachnoid space?
Virchow-Robbins Space
Why do areas in the brain with severe damage become cavitary over time?
The brain does not heal like other areas in the body and it will no become fibrous/infarcted.
The structure that is injured within the brain is not replaced when you have a cellular injury.
What is the cause of spheroids?
Can occur post-traumatically with “Diffuse Axonal Damage”
Which acute neuronal injury is going to present with neurons that are ballooned and their cytoplasmic structures are gone?
Central Chromatolysis
Gliosis, gemistocytic ______ , fibrillary _______ , Rosenthal Fibers and corpora amylacea are all patterns of injury and repair when dealing with ________ .
Astrocytes
Is the lymphatic inflammatory response typically noted/seen in parnchymal disorders of the brain?
NO!
Tights junctions are a major component of the Blood Brain Barrier, what are the other two components?
- Basal Lamina of the Endothelial Capillaries
2. Perivascular Astrocytes End-Feet
Which cell in the CNS plays a major role in wound healing?
Astrocytes
Which fibers are abundant in the Posterior Fossa of Pilocytic Astrocytomas?
Rosenthal Fibers
__________ are basophilic, lamellated polyglucosan bodies that accumulate in astrocytic processes with age, most in subpial locations.
Corpora Amylacea
Pia Mater and Arachnoid Mater are collectively known as the ________ .
Leptomeninges
Which of the Meningial layers are involved in Early/Later Meningitis?
Early = Leptomeninges
Late = Dura Mater
True or False. Oligodendroglias are not as aggressive as astrocytomas.
True
Which glial cell has a “fried egg” appearance?
Oligodendrocytes
Which glial cell is responsible for lining of the Ventricular System in the brain?
Ependymal Cells
Differentiate between the central canal in a Child vs. an Adult.
Child - Widely Patent
Adult - Obliterated
Which cells in the CNS are not considered to be glial cells; rather, they are considered to be “fixed tissue phagocytes”?
Microglial
_________ are involved in responding to infection AND thought to have a role in the normal neural development in human beings (“pruning” of excess neurons).
Microglia
Which cell is described as a “small rod-shaped cell”?
Microglia
Which infectious agents can show signs of microglia nodules?
- HIV
2. Rocky Mountain Spotted Fever (Rickettsial Species)
Generalized Brain Edema, Increased CSF volume and Expanding mass lesion are going to cause ___________ .
Increases in Intracranial Pressure
What is the most common cause of Increased Intracranial Pressure? What is it frequently associated with?
Generalized Brain Edema
Frequently associated with Acute Infections (typically pyogenic infections)
What is the most common malignancy in the Brain?
Glioblastoma
Which type of edema is caused by the blood-brain barrier disruption (break in tight junctions or podocyte end-feet) and increased vascular permeability allowing fluid to shift from the Intravenous Compartment to intercellular spaces of the brain?
Vasogenic Edema (results of space-occupying lesions aka tumors)
Which type of edema is caused by an increase in intracellular fluid secondary to neuronal, glial, or endothelial cell membrane injury (i.e. generalized hypoxic/ischemic damage)?
Cytotoxic Edema
Which sub-class of aquaporin channels are located in the brain?
Aquaporin-4
In cytotoxic edema, glial cells typically ________ while neurons are relatively _______ . *** At least initially.
Swell
Spared
What is the use of the Pineal Gland landmark on head CTs?
To detect midline shifts (herniations)
Which type of Hydrocephalus will present with symmetrically dilated ventricles because the ventricular system is intact _______ the level of the arachnoid granulations/dural sinus?
Communicating
Below
Which type of Hydrocephalus will present with unsymmetrically dilated ventricles because there is an obstruction of CSF flow _______ the level of the arachnoid granulations/dural sinus?
Non-Communicating
Below
How many mL of CSF is considered normal?
120-130 mL
What are the vessels that make up the “dual supply” to the brain?
- Vertebral Arteries
2. Internal Carotid Artery
What is the most common cause of Non-Communicating Hydrocephalus in children?
Stenosis of the Cerebral Aqueduct of Sylvius
Which micro-organism is going to cause Neurocysticercosis which can lead to Hydrocephalus?
Taenia Solium
Which form of hydrocephalus can present with Bilateral Cerebral Cortical Atrophy?
Which Patient population is this commonly seen in?
How does this affect ICP?
Ex vacuo
Pts with Alzheimer’s / Other nuerodegenerative Diseases
No change in ICP
What are the two types of Normal Pressure Hydrocephalus (NPH)?
- Idiopathic - Most Common, Drainage of CSF is blocked gradually over time and the excess builds up slowly
- Secondary - subarachnoid hemorrhage, trauma, tumor, infection, or a complication of cranial surgery
What is the classic triad for Pts that have Normal Pressure Hydrocephalus (NPH)?
“Weird Walking Water”
- Dementia
- Magnetic Gait (no rigidity or tremor)
- Urinary Incontinence
When is a Lumbar Tap contraindicated? Why?
In Pts with HIGH ICP
If you mess up the Lumbar Tap you can cause HERNIATION of the brain!
What are two classic signs of ICP?
- Headache
2. Papilledema
Which type of Brain herniation is going to go through the Falx Cerebri?
Subfalcine Herniation
Which type of brain herniation is going to go through the tentorium cerebelli?
Transtentorial Herniation
Which type of brain herniation is going to go through the foramen mangum?
Tonsillar Herniation
Which structres will be compromised with a Subfalcine Herniation?
Anterior Cerebral Artery
Which structres will be compromised with a Transtentorial Herniation?
- CNIII
- Posterior Cerebral Artery
- Compression of the Brainstem
Which structres will be compromised with a Tonsillar Herniation?
Compression of the Brainstem
_____________ is a result of the compression of the cerebellar peduncle against the tenorium cerebelli due to transtentorial herniation and produces an ipsilateral hemiparesis or hemiplegia.
Kernohan’s notch Phenomenon
If you have a RIGHT hemisphere trans-tentorial herniation, it will cause a Kernohan’s notch in the __________ Cerebellar Peduncle which will result in _________ - sided motor impairment.
Left
Right
Explain how you can develop a melanoma without having any external source of the melanocytes on the skin.
Melanocytes develop from neurocrest cells. During development, some of the neurocrest cells can be left behind with the neural tube. You can have proliferation of melanocytes in the medulla which can lead to Leptomeningeal Melanocytes!
Which congenital disease will present with non-progressive neurologic motor defects generally due to ischemia during vaginal birth (perinatal brain injury)?
Cerebral Palsy
What are three important things to consider when you have a congenital defect on your hands?
- Maternal cause
- Obstetric cause
- Fetal cause
The embryonic period of development lasts until which week?
Week 9
What is the most common osmotically active protein in the blood of a fetus?
What should you immediately suspect when you find this protein in an amniocentesis?
Alpha-fetoprotein
Neural Tube Defect
Why are neural tube defects so scary?
If you get an infection it can RAPIDLY ascend to the brain!
Which neural tube defect is associated with incomplete closure of the vertebral arches?
Spinal dysraphism or bifida
Which neural tube defect is associated with the brain protruding into the defect?
Encephalocele
Which neural tube defect is associated with no formation of cerebral cortices and has a “Frog-Like” appearance?
Anencephaly
Megalencephaly (big brain), Microcephaly (small brain), Lissencephaly (lack of development of gyri and sulci), Pachygryria (few gyri aka incomplete Lissencephaly), Polymicrogyria (excessive gyri in the brian), Neuronal heterotopias, Holoprosencephaly (Failure of central midline structures to form) and Agenesis of the corpus callosum are all examples of _________ .
Forebrain Malformations
Arnold-Chiari Malformation and Dandy-Walker Syndrome are both examples of ________ .
Posterior Fossa Malformations
Which malformation is going to present with a small posterior fossa, cerebellar vermis extending down into the foramen magnum and polymicrogyria (too many gyri)?
Arnold-Chiari Malformation
Which malformation is going to present with a large posterior fossa, a “wing-out” formation of the cerebellum (NO cerebellar vermis) and CSF drainage that is compromised due to the foramina of Luschka and Magendie not being formed?
Dandy-Walker Malformation
Which type of skull fracture is going to present with CSF bloody otorrhea (out the ears), Raccoon Eyes and Battle’s sign (reflecting orbital and mastoid hematomas)?
Basilar Skull Fracture
The following definition is describing _______ . “There is some level of (nondegenerative, noncongenital) damage to the brain resulting from external mechanical force, such as rapid acceleration or deceleration, impact, blast waves, etc. There is generally an associated diminished or altered state of consciousness. Brain function is temporarily or permanently impaired and structural damage may or may not be detectable with current technology.”
Traumatic Brain Injury
Many scientists believe that repeated blows to the head increase risks for developing ________________ , leading to progressive loss of normal brain matter and an abnormal buildup of a protein called ______ .
Chronic Traumatic Encephalopathy
Tau
What does cerebellar tonsillar scarring mean?
There was a tonsilar herniation in the past that was resolved!
Which structures are most susceptible to direct parenchymal injuries?
Crest of the Gyri
What type of formations are going to be present with parenchymal injury?
Spheroid formations from “diffuse axonal injury”
Which type of hematoma is going to present with:
- Arterial Bleeds
- Shearing of the Middle Meningeal Artery
- Smooth contour at the base of the bleed (lens-shaped)
- Medical Emergency
- Dura is peeled off the skull
Epidural Hematomas
Which type of hematoma is going to present with:
- Venous Bleeds
- Shearing of the Bridging Veins
- Tend to stop bleeding on their own
- Jagged contour at the base of the bleed
- Not necessarily a medical emergency
- Dura is still attached to the skull
Subdural Hematomas
Post-traumatic hydrocephalus, Chronic Traumatic Encephalopathy and seizure disorders can all be an outcome of _______ .
Brain Trauma
Some patients (a small %) will immediately lose consciousness, wake up for a few hours, and then lose consciousness a second time, but the period BETWEEN the two periods of consciousness is known as the _________ .
Lucid Interval
*** Not DIAGNOSTIC but can be associated with an Epidural Hematoma
