Intro to Neuropathology

Question 1

Red Neurons are an indication of…?

Answer 1

Acute Insult (12-24 hrs)

intense eosinophilia (source of “red”)

nucleus will be pyknotic (raisin-like)

loss of nucleolus, nissl substance

Question 2

What are some causes of acute insult injury to neurons?

Answer 2

-Hypoxia, hypoglycemia, trauma

Question 3

What are some causes of Intranuclear Neuronal Inclusions?

Answer 3

Herpes Cowdrybody,CMV both intranuclear and cytoplasmic

Question 4

An “Owl’s eye nuclear inclusion body” ban be seen in….?

Answer 4

CMV Infection

Question 5

How is Astrogliosis identified?

Answer 5

-characterized by hypertrophy and hyperplasia of astrocytes (get bigger and get more of them)

Question 6

A patient with chronic liver disease may present with what type of gliosis?

Answer 6

Alz Type 2 Astrocyte

• extremely large, pale staining, intranuclear glycogen droplet, prominent nuclear membrane & nucleolus
• seen in hyperammonemia, Wilson disease, hereditary metabolic disorder of the urea cycle

Question 7

What is the name for a slow-growing tumor in the brain that contains mostly keratinized tissue, and is the most common cause of pan-hypopituitarism in children?

Answer 7

Craniopharyngioma

Question 8

What are Rosenthal Fibers?

Answer 8

• Thick, Elongated, Brightly Eosinophilic, Irregular
• occurs within astrocytic processes
• Contains 2 Heat Shock Proteins: alpha B-crystalline and HSP 27

Question 9

What type of tumors are most closely associated with Rosenthal Fibers?

Answer 9

Pilocytic Astrocytoma

-Overall, when you see Rosenthal Fibers think of something that is benign, and slow-growing/ longstanding gliosis

Question 10

What is a distinctive feature of Corpora Amylacea?

Answer 10

concentric layers, adjacent to pial surface

Question 11

What is the role of Microglia, and how can we identify them?

Answer 11

They are the macrophages of the CNS, and thus have the same surface markers CR3 and CD68

Question 12

What are Microglial Nodules?

Answer 12

An aggregate of microglia around small foci of necrosis

Question 13

The congregation of microglia around a dying neuron is known as…..?

Answer 13

Neuronophagia

Question 14

What are Ependymal Granulations?

Answer 14

Disruption of Ependymal Lining and Proliferation of Subependymal Astrocytes

irregularities on ventricular surfaces

Question 15

Define Vasogenic Edema

Answer 15

increased extracellular fluid due to BBB compromise

Fluid from blood goes into brain tissue, no lymphatics to drain it

Often follows ischemia injury, trauma, tumor

Question 16

Define Cytotoxic Edema

Answer 16

increased intracellular fluid secondary to cellular injury

(neuronal, glial, or endothelial cell membrane insult)

-often seen with hypoxia/ischemia or metabolic insult

Question 17

What are the effects of Cerebral Edema on the physical characteristics of the brain?

Answer 17

Gyri Flattened, Sulci Narrowed, Ventricles Compressed

Can lead to herniation

Question 18

If a patient presents with papilledema, what must you consider?

Answer 18

hydrocephalus

papilledema is caused by increased intracranial pressure

Question 19

What is a hallmark of communicating hydrocephalus that can be seen on on CT?

Answer 19

Symmetrically Enlarged Ventricles

(due to the excess CSF)

Question 20

What is one rare cause of increased CSF production?

Answer 20

Choroid Plexus Papilloma

Question 21

Define Pyogenic Meningitis

Answer 21

suppurative exudate covering the brainstem and cerebellum

-seen more often in tuberculosis

Question 22

What are the characteristics of Hydrocephalus Ex-Vacuo?

Answer 22

• dilation of the ventricles
• shrinkage of brain substance
• CSF pressure is normal

Question 23

If a patient presents with dementia-like manifestations, along with Parkinson/Alzheimer disease, what must we also consider?

Answer 23

Normal-pressure hydrocephalus (NPH)

-develops slowly, can be treated and reversed

Question 24

What are some characteristics of an NPH that may cause confusion with other dx’s?

Answer 24

• Parkinsonian gait (shuffling, tendency to fall backwards, broad-based gait)
• Dementia
• urinary incontinence

Question 25

What are the different types of herniations due to increased intracranial pressure?

Answer 25

Subfalcine: cingulate gyrus displaced under the falx Transtentorial: Medial Aspect of the temporal love compressed against the tentorium Tonsillar: Cerebellar tonsils displaced through the foramen magnum

Question 26

What is characteristic of a Transtentorial Herniation?

Answer 26

CN3 is affected, so ## Footnote **dilated pupil & impaired eye movement**

Question 27

What are some consequences of a Subfalcine Herniation?

Answer 27

- ACA compression - can be clinically silent

Question 28

What are some consequences of a Transtentorial Herniation?

Answer 28

- PCA compression (visual field defect) - CN III compression (blown pupil) - **cerebral peduncle compression** (**ipsilateral paresis / Kernohan's notch)** - Sylvian aqueduct occlusion (hydrocephalus) - Duret hemorrhages

Question 29

What is a Duret Hemorrhage?

Answer 29

_Sequela of a Transtentorial Herniation_ caused by stretching of the penetrating branches of the basilar artery as the midbrain descends, causing **secondary hemorrhagic lesions in the midbrain and pons**

Question 30

What is the difference between Liquefactive and Coagulative Necrosis?

Answer 30

In **Liquefactive Necrosis**, **no architectural remnants**

Question 31

The most common CNS malformation is caused by what?

Answer 31

The most common malformation, **Neural Tube Defects**, are caused by **Folate Deficiencies** -usually before day 28

Question 32

What are Neuronal Heterotropias?

Answer 32

Collection of neurons in inappropriate places (not a tumor, not a malignancy) commonly associated with _epilepsy_ that doesn't respond to treatment

Question 33

What is a Dandy-Walker Malformation?

Answer 33

_Enlarged_ Posterior Fossa; **expanded roofless fourth ventricle** cerebellar vermis absent or rudimentary

Question 34

What is an Intraparenchymal Hemorrhage?

Answer 34

Damage to the Germinal Matrix, only seen in premature infants/ developing brains happens to stem/progenitor cells in this region (between thalamus and caudate nucleus)

Question 35

What is a diastatic fracture?

Answer 35

Fracture that crosses a suture line

Question 36

Which kind of fracture can cause CSF drainage from ear or nose?

Answer 36

Basal Skull Fracture

Question 37

What is a coup-contrecoup contusion, and what type of injury would cause it?

Answer 37

One side of the brain hits the skull and is bruised, and then the brain rebounds back and hits the opposite side, so you have matching contusions on opposite sides. Caused by a **Parenchymal Injury**

Question 38

How is a remote contusion identified?

Answer 38

yellowish-brown plaque that is depressed, retracted, involving crests of gyri usually evident of an _old lesion_

Question 39

What is a Diffuse Axonal Injury

Answer 39

_High torque_ on the brain causes stretching of axons, which can lead to damage (tearing, swelling, etc) **seen in SBS** Seen on histology with **silver stain** or **amyloid precursor protein (APP)** & **alpha-synuclein** immunostains Also easily seen on MRI

Question 40

What type of blood accumulates in the epidural space following a skull fracture?

Answer 40

**Arterial** blood Associated with _rapidly evolving neurologic symptoms, requires intervention_

Question 41

What type of blood accumulates in the subdural space following trauma?

Answer 41

**Venous** blood Associated with slowly evolving neurologic symptoms, often with a delay from the time of injury

Question 42

What is commonly associated with a Subarachnoid Hemorrhage?

Answer 42

**Sudden Onset of severe headache** **"worst headache of my life"** -can be associated with rapid neurologic deterioration

Question 43

Which blood vessel is most likely to be ruptured with a skull fracture?

Answer 43

Middle Meningeal Artery