Basic Concepts in Neuropathology (Bruch)

Question 1

non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the central nervous system and peripheral nervous system

Answer 1

glia

Question 2

From which embryologic layer are glial cells derived?

Answer 2

neuroectoderm (neural tube epithelium)

Question 3

Which of these is not a primary function of astrocytes?

A. Provide neurons with nutrients

B. Regulate extracellular ion concentration and transmission of electric impulses

C. Myelination of CNS axons

D. Repair and scar formation in the brain

E. Maintenance of the blood brain barrier

Answer 3

C. This role is performed by the oligodendrocytes, which are similar to the Schwann cells of the PNS.

Question 4

these cells looks similar to lymphocytes microscopically, but many times they appear to be surrounded by a small clear halo:

Answer 4

oligodendrocytes

Question 5

these cells vary in their size, structure, physiology, function, connectivity and blood supply; may be arranged topographically (sometimes somatotopically) into aggregates or layers

Answer 5

Neurons

Question 6

these cells line the ventricular system and are closely related to the cuboidal cells of the choroid plexus:

Answer 6

ependymal cells

Question 7

this concept relates the idea that sets of related neurons, even those that are not regionally located next to one another, can be singled out for destruction

Answer 7

selective vulnerability;

*selective vulnerability results from a combination of factors, including demands on ATP production, specific neurotransmitter metabolism, microcirculatory regulation, neuronal connections, AS WELL AS regional anatomy.

Question 8

these are the two main disadvantages discussed regarding the blood brain barrier

Answer 8

keeps out white blood cells; keeps out drugs

Question 9

these cells are critical to maintaining the blood brain barrier, with their high resistance tight junctions that connect them

Answer 9

cerebral capillary endothelial cells (see image for details)

Question 10

this barrier is formed by tight junctions of the choroid plexus and arachnoid cells of the leptomeninges

Answer 10

blood-CSF barrier

Question 11

what is the primary function of the cells shown below?

Answer 11

they make CSF (these are choroid plexus cells lining the ventricles

Question 12

What is the primary function of the cells shown here?

Answer 12

absorb CSF (these are the arachnoid granulations)

Question 13

this doctrine states that a volume increase of any one of the components of the calvaria - brain, tissue, blood, CSF, or other brain fluids - will produce increased intracranial pressure because the bony calvaria rigidly fixes the total cranial volume

Answer 13

Monro-Kellie doctrine

Question 14

this is the most common type of cerebral edema and can be due to trauma, abscess, tumor or hemorrhage which causes disruption of the BBB

Answer 14

vasogenic edema

Question 15

this is an increase in intracellular fluid due to cell membrane injury (hypoxic/ischemic, toxic or metabolic injury)

Answer 15

cyototoxic edema

Question 16

Which of the following statements regarding hydrocephalus is TRUE?

A. Noncommunicating hydrocephalus is due to an obstruction outside the ventricular system

B. Only communicating hydrocephalus implies impaired flow of CSF

C. Communicating hydrocephalus is a focal enlargement due to excessive accumulation of CSF

D. Hydrocephalus ex vacuo occurs with dilatation of the ventricular system to compensate for loss of brain parenchyma

E. All forms of hydrocephalus lead to increased intracranial pressure

Answer 16

D.

A is incorrect: Noncommunicating hyrdrocephalus is due to an obstruction within the ventricular system that causes a focal enlargement

B is incorrect: Both communicating and noncommunicating hydrocephalus imply impaired flow of the CSF through the brain

C is incorrect: Communicating hydrocephalus is an enlargement of the entire system due to an obstruction outside the ventricular system

E is incorrect: In hydrocephalus ex vacuo there is a compensatory increase in CSF volume due to susbtantial loss of brain parenchyma, and in this setting there is no increase in ICP.

Question 17

An obstruction of the cerebral aqueduct would be considered a:

A. Noncommunicating hydrocephalus

B. Communicating hydrocephalus

C. Hydrocephalus ex vacuo

D. Herniation

Answer 17

A

Question 18

Meningitis that impairs the function of arachnoid granulations is considered a:

A. Noncommunicating hydrocephalus

B. Communicating hydrocephalus

C. Hydrocephalus ex vacuo

D. Herniation

Answer 18

B

Question 19

The hydrocephalus pictured below is likely due to:

A. Noncommunicating hydrocephalus

B. Communicating hydrocephalus

C. Hydrocephalus ex vacuo

D. Cannot be determined

Answer 19

D. You would need to see the entire ventricular system in order to be able to determine the cause.

Question 20

this type of herniation may result in anosmia, as well as contralateral motor and sensory deficits, particularly of the lower limbs and perineum (urinary incontinence)

Answer 20

subfalcine herniation - due to compression of the ACA

Question 21

patients with a “blown pupil” and ipsilateral hemiparesis may be experiencing what type of herniation?

Answer 21

uncal (transtentorial);

progressive herniation of the uncus compromises CNIII and puts pressure on the midbrain, pushing it to the contralateral side where it compresses the cerebellar peduncle. This results in ipsilateral hemiparesis and is called “false localizing sign”.

Question 22

The hydrocephalus seen in the picture below is likely due to:

A. Noncommunicating hydrocephalus

B. Communicating hydrocephalus

C. Hydrocephalus ex vacuo

D. Cannot be determined

Answer 22

C. In this image you see enlarged ventricles as a result of tissue loss (atrophy) compared to control. This would not be associated with increased ICP

Question 23

this type of herniation results when the cingulate gyrus becomes displaced under the edge of the falx; may be associated with compression of the anterior cerebral artery

Answer 23

subfalcine herniation

Question 24

this feature of uncal herniation is due to linear midline hemorrhages in the midbrain and pons that result from the tearing of penetrating veins and arteries supplying the brainstem

Answer 24

duret hemorrhages

Question 25

this type of herniation is a life-threatening emergency, because it causes compression of the brainstem and compromises vital respiratory and cardiac centers in the medulla

Answer 25

tonsilar herniation - displacement of the cerebellar tonsils through the foramen magnum

Question 26

Which of the following statements regarding the patient with the gross specimen below is true?

A. This patient had brainstem compression which compromised vial respiratory centers in the medulla

B. This patient had atrophy of the parenchyma and with a compensatory increase in CSF volume

C. This patient had a blown pupil and ipsilateral hemiparesis

D. This patient had a noncommunicating focal obstruction within the ventricular system

E. This patient had ACA compression with contralateral sensory and motor loss of the lower limbs

Answer 26

E. This pictures shows a midline shift with subfalcine herniation, which would compromise the ACA.

Question 27

what is it?

Answer 27

uncal herniation, compressing the 3rd nerve and PCA

Question 28

the neurons in the picture below represent a spectrum of changes that accompany what type of acute condition?

Answer 28

acute irreversible hypoxia/ischemic injury; these are “red” (dying) neurons

Question 29

the feature indicated by the arrows is seen in neuronal degeneration and is known as _____ ______.

Answer 29

axonal spheroids

Question 30

the feature seen in this picture is a common finding in degenerative disease like Alzheimers:

Answer 30

neurofibrillary tangles

*much more obvious with bielschowsky silver stain (below)

Question 31

key features of parkinson’s disease includes loss of palor of the substantia nigra as well as these neuronal inclusions shown below:

Answer 31

lewy bodies

Question 32

gliosis is the marker of neuronal cell loss, and the most important histopathologic indicator of CNS injury REGARDLESS of etiology; what cell type undergoes a morphologic change in response to injury, and is responsible for this process?

Answer 32

astrocytes

this is scarring of the brain, and you have to lose 50-60% of your neurons in order for this to be evident. Note the reactive proliferation of these cells characterized by abundant, eccentric, pink cytoplasm (left) and the well defined reactive astrocytes with their prominent processes on the GFAP stain (right):

Question 33

the feature indicated below is characteristic of what disease process?

Answer 33

chronic gliosis (or also low grade gliomas) - these are rosenthal fibers

Question 34

The green arrows in the section below show what process that has occurred in the subcortical white matter of the forebrain?

With what disease is this finding consistent?

What do you think the red arrows indicate?

Answer 34

the green arrows show chronic demyelination of axons - this would be characteristic of multiple sclerosis.

The red arrows indicate ‘shadow plaques’, in which the demyelinated axons have undergone remyelination. This section illustrates two important points: first, that remyelination can occur as a spontaneous regenerative response in the adult human brain; and second, that this process does not always occur and many lesions remain demyelinated.

(source: nature reviews: neuroscience)