Neuropathology

Question 1

List the four types of glial cells in the central nervous system.

Answer 1

Astrocytes
Microglia
Oligodendrocytes
Ependymal cells

Question 2

Astrocytes do what

Answer 2

responsible for repair and scar formation, also get nutrients

Question 3

Oligodendrocytes do what

Answer 3

myelin formation in CNS

Question 4

Ependymal cells do what

Answer 4

line ventricular system

Question 5

Microglia do what

Answer 5

macrophages in CNS

Question 6

Recognize and name the histologic change in the neuron in response to hypoxia/ischemia.

Answer 6

Red neuron

Question 7

Describe what is meant by the term reactive gliosis.

Answer 7

Astrocytes –> hypertrophy and hyperplasia

No fibrous scar –> glial scar

Most important histopathologic indicator of CNS injury

Question 8

Explain the clinical implications of uncal herniation.

Answer 8

CN III (pupil dilated, impairment of ocular movement on side of lesion)
Post. cerebral artery –> damage to visual cortex (occ lobe)
contralateral cerebral peduncle –> hemiparesis ipsilateral to side of herniation
midbrain and pons = duret hemorrhages

Question 9

Describe the pathophysiology of hydrocephalus ex-vacuo.

Answer 9

Atrophy of brain mass –> dilation of ventricles

No block

Question 10

Histology of reactive gliosis

Answer 10

Develop prominent cell processes and homogenous cytoplasm, development of elongated, granular, hypereosinophilic proteinaceous deposits called Rosenthal fibers “piloid gliosis”

Question 11

Rosenthal fibers

Answer 11

eosinophilic structures within astrocytic processes found in regions of long-standing gliosis, also seen in brain tumors

Question 12

Describe the physical exam findings in someone with a basal skull fracture.

Answer 12

Distal hematomas =
Battle’s signs (retroauricular ecchymosis)
Raccoon eyed (bilateral periorbital fractures)
CSF draining d/t dural tears

Question 13

List the typical sequence of events in a concussive episode.

Answer 13

instantaneous onset of transient neurologic dysfunction including loss of consciousness, temporary respiratory arrest, and loss of reflexes
Amnesia of the event

Question 14

Differentiate between the causes of an epidural hematoma versus a subdural hematoma.

Answer 14

E: Trauma to the skull especially in the region of the temporal bone, can lead to the laceration of the artery if the fracture lines cross the course of the vessel - middle meningeal artery usually. Blood builds up above dura (under skull)

SH: cerebral veins through subarachnoid and subdural space, prone to tearing through subdural space w/ displacement of brain

Question 15

basal skull fracture

Answer 15

serious, most commonly involving petrous portion of temporal bone, external auditory canal and TMJ

Question 16

Clinical picture EH vs SH

Answer 16

EH: patients lucid for several hours between the moment of trauma and the development of neurologic signs

SH: Can develop slowly, over time. Can get chronic rebleeding. Nonlocalizing, headache & confusion

Question 17

Imaging EH vs SH

Answer 17

Epidural - lens shaped

Subdural - crescent shaped

Question 18

Name the aberrant enzyme in Tay-Sachs disease

Answer 18

Hexosaminidase A –> accumulation of ganglioside in all tissues

Question 19

List the common causes of vitamin B1 (thiamine) deficiency and describe a possible clinical presentation.

Answer 19

Beriberi
Wernicke encephalopathy = psychotic symptoms or ophthalmoplegia abruptly –> Korsakoff = memory disturbances or confabulation

chronic alcoholism, gastric disorders

Question 20

Describe the histologic findings in a section of spinal cord from a patient with longstanding vitamin B12 deficiency.

Answer 20

Swelling of myelin layers, producing vacuoles that begin at midthoracic level of spinal cord, with time axons in both ascending in posterior and descending pyramidal tracts degenerate

Question 21

Describe the resulting histologic and clinical findings of Tay Sachs

Answer 21

Begins in early infancy, death w/in several years
Developmental delay, then paralysis then loss of neurologic function
Cherry red spot in macula
Intracellular accumulation of ganglioside (fat neurons)

Question 22

Describe the clinical presentation of Guillain-Barre Syndrome.

Answer 22

Acute Inflammatory Demyelinating Polyneuropathy
ascending paralysis –> weakness beginning in distal limbs and rapidly advancing to affect proximal muscle function
preceded by acute illness
(Campylobacter jejuni, CMV, EBV, M. pneumoniae)
Deep tendon reflexes disappear early, symmetric ascending paralysis w/ some loss of sensation
Elevated protein, normal lymphocytes

Question 23

Identify the key histopathologic finding in tuberculous leprosy.

Answer 23

Nodular granulomatous inflammation in the dermis that injures cutaneous nerves in the vicinity

Question 24

Identify the clinical presentation of Charcot-Marie-Tooth disease.

Answer 24

Slowly progressive muscular atrophy of the calf or distal muscle weakness, or associated secondary orthopedic problems of the foot (high arches, hammer toes, muscle atrophy)

Question 25

histologic appearance of Charcot marie tooth

Answer 25

Consequences of repetitive demyelination and remyelination: formation of multiple “onion bulbs”
Redundant layers of Schwann cell hyperplasia surrounding individual axons may result in enlargement of peripheral nerve which is palpable: hypertrophic neuropathy