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Neonatal Pathophysiology > Neurology of the Newborn > Flashcards

Flashcards in Neurology of the Newborn Deck (167)
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1

What are the 3 layers of cells in early embryologic development?

endoderm, mesoderm and ectoderm

2

What will the endoderm form?

the epithelium

3

What will the mesoderm form?

muscle and connective tissue

4

What will the ectoderm form?

skin and the nervous system

5

How does the CNS initially appear?

the ectoderm thickens and flattens to form the neural plate; one of the first systems to develop

6

When does the neural plate appear in embryologic development?

at the beginning of the 3rd week of life

7

How does the neural groove form?

the lateral edges of the neural plate elevate to form the neural folds, and subsequently creating a neural groove

8

What does fusion of the neural folds create?

the neural tube

9

When does the formation of the neural fold occur in embryologic development?

beginning of the 4th week of life; fusion occurs at the level of the 4th cervical vertebrae

10

In what direction does neural tube fusion occur?

proceeds from cephalad and caudal directions

11

What are neuropores?

fusion delayed at the cranial and caudal ends leaves openings at either pole

12

What do the neuropores create?

open communication between neutral tube and the amniotic cavity

13

When is the cranial neuropore expected to close?

on day 25 after conception

14

When is the caudal neuropore expected to close?

on day 27 or 2-3days after

15

What is the physiologic cause of a neural tube defect?

failure of the neural tube to close between 25-28 days after conception

16

What diagnosis accounts for most the CNS congenital anomalies?

NTD

17

How prevalent are NTD in the US?

second most common congenital anomaly (after CHD)

18

What are the risk factors for NTDs?

1) folic acid deficiency
2) maternal diabetes (poor glycemic control in the first trimester is a high risk factor)
3) Maternal exposure to certain medications (anticonvulsants and folic acid antagonists)
4) previous infants with NTDs

19

If a family had a child with a NTD, what is their risk for subsequent pregnancies?

with 1 child with a NTD, the risk is 2-4%; if > 1 child with a NTD, the risk is > 10%

20

What medications are associated with an increased risk for NTDs?

phenytoin, phenobarb, carbamazepine and trimetoprima

21

What is the greatest measure of NTD prevention?

folic acid supplementation before conception (1-3mo) and during the first month of pregnancy can prevent up to 70% of NTD cases.

22

What is the recommended doseage of folic acid?

0.4mg for normal women; mother's at increased risk should take 4mg throughout their pregnancy

23

What are the different forms of NTDs?

1) Anencephaly
2) Encephalocele
3) Myelomeningocele

24

What is Anencephaly?

the most severe form of NTD, not compatable with life.
failure of the cephalic end of the neural tube to close and results in degredation of the forebrain

25

What is the extent of structural damage with an Anencephaly diagnosis?

absence of scalp, skull and brain tissue, may be able to visualize the brain stem, exposed hemorrhagic fibrotic tissue; may have brain stem sparing

26

How is Anencephaly diagnosed?

will have elevated maternal alpha fetoprotein; US 14-15 weeks GA

27

What is the rate of spontaneous abortion in infants with Anencephaly?

65%; most families elect to abort child

28

Why do infants with Anencephaly typically continue on into post term maturation?

pituitary and adrenal functions are important in triggering labor; these structures are typically underdeveloped and labor may subsequently occur spontaneously

29

What is the survival expectancy of infants with Anencephaly?

75% will be stillborn, other infants typically die within a few hours, days or a few weeks

30

What is the clinical presentation of infants with Anencephaly?

unconscious with varying degrees of brain stem function