Parks: CNS Pathology Basic Concepts

Question 1

What is a contusion?

Answer 1

contusion is a lesion in the brain that occurs when the brain hits the skull

Question 2

What happens to the brain after an acute contusion?

Answer 2

necrosis and hemorrhage; in addition, the brain swells and causes cerebral edema

Question 3

What is one type of brain hernia that you should really worry about? Why?

Answer 3

uncal/transtentorial herniation; this might affect the brain stem

Question 4

What are three types of hernias of the brain?

Answer 4

subfalcine (falx) herniation
transtentorial herniation
tonsillar herniation

Question 5

When the uncus protrudes underneath the tentorium, what is this called?

Answer 5

uncal herniation

Question 6

Which nerve is the uncus likely to impinge? What is one symptom that may occur as a result?

Answer 6

ipsi CN 3 (occulomotor); dilated pupil initially - eventually, the pupil may move down and out

Question 7

When the uncus compresses the third nerve, what causes the coma that follows?

Answer 7

compression of the midbrain against the opposite tentorial edge

Question 8

What is Duret hemorrhage?

Answer 8

hemorrhage in the mid-brain and pons

Question 9

Why is duret hemorrhage such a problem?

Answer 9

can compress important components of the brain stem, such as the brain stem respiratory center

Question 10

When you have ischemic necrosis of the occipital lobe, what are the consequences? What is the artery involved?

Answer 10

vision loss; posterior cerebral artery

Question 11

What time period during embryonic development is most critical for CNS development?

Answer 11

weeks 3-5

**this is when neural tube defects are most likely to occur

Question 12

What is the difference b/w a meningocele and a myelomeningocele?

Answer 12

meningocele is when there is a sac like protrusion off of the meninges;
myelomeningocele is when the spinal cord actually herniates out into the sac like protrusion in addition to the meninges

Question 13

What test do you use to look for neural tube defects?

Answer 13

Alpha fetal protein

Question 14

Recommendations for decreasing the risk of neural tube defects?

Answer 14

iron and folic acid supplements

Question 15

Enlargement of ventricles

Answer 15

hydrocephalus

Question 16

One of the most frequent congenital malformations of the CNS

Answer 16

hydrocephalus

Question 17

Risk factors for hydrocephalus?

Answer 17

lack of prenatal care
maternal diabetes
maternal HTN
maternal consumption of alcohol
infections (parvo B19)
maternal antidepressant use

Question 18

Localized obstruction within ventricular system. Only that focal ventricle enlarges while the other ventricles do NOT enlarge.

Answer 18

non-communicating hydrocephalus

Question 19

Entire ventricular system enlarges. This usually from reduced CSF resorption

Answer 19

communicating hydrocephalus

Question 20

What are most cases of hydrocephalus caused by?

Answer 20

impaired resorption or an obstruction; rarely overproduction of CSF

Question 21

Two forms of cerebral edema

Answer 21

vasogenic edema

cytotoxic edema

Question 22

Following trauma; tumors also show this as does inflammation such as encephalitis. Fluid shifts from vascular into extracellular space.

Answer 22

vasogenic edema

Question 23

Following stroke and hypoxic-ischemia insult (cardiac arrest); neurons, glia are injured.

Answer 23

cytotoxic edema

Question 24

Lateral displacement of the midbrain may compress the opposite (blank), producing a Babinski’s sign and hemiparesis contralateral to the original hemiparesis. This is called (blank) sign

Answer 24

cerebral peduncle; Kernohan-Woltman

Question 25

Which arteries may be compressed when herniation occurs?

Answer 25

anterior and posterior cerebral arteries

Question 26

What is Kernohan’s notch?

Answer 26

compression of opposite cerebral peduncle

Question 27

What is tonsillar herniation?

Answer 27

when the cerebellum herniates downward through the foramen magnum