Congenital Hypothyroidism Flashcards Preview

Digestive, Endocrine, and Metabolic Systems > Congenital Hypothyroidism > Flashcards

Flashcards in Congenital Hypothyroidism Deck (22):
1

The ___________ is the first endocrine gland to develop.

thyroid

2

What are the two embryonic origins of the thyroid?

Follicular cells: pharyngeal endoderm
Calcitonin-secreting cells: neural crest

3

The thyroid originates from endoderm between ____________.

the first and second pharyngeal arches

4

When does the thyroid complete its descent?

7th week

5

When do the follicular cells differentiate and begin to trap iodide?

Weeks 10-12

6

What are DIT and MIT?

Diiodotyrosine and monoiodotyrosine

7

TSH is detectable at _________ weeks gestation.

12

8

Although fetuses can make T4, maternal T4 can _______________.

pass through the placenta, thus limiting some of the fetal effects of congenital hypothyroidism

9

What is the incidence of congenital hypothyroidism?

1:2,000

10

Not having sufficient levels of T4 causes what in children?

Neurologic impairment and decreased linear growth

11

The most common cause of congenital hypothyroidism is _____________.

thyroid dysgenesis: caused by defective migration or differentiation of cells (this accounts for 85% of congenital hypothyroidism)

12

Less common causes of congenital hypothyroidism include _________________.

defects in thyroid hormone synthesis, TSH resistance, or central pituitary dysfunction

13

Dysgenesis of the thyroid can be ____________.

aplastic, hypoplastic, or ectopic

14

Some cases of thyroid dysgenesis (2%) are caused by ____________.

genetic defects (such as in PAX8)

15

What are signs and symptoms of congenital hypothyroidism?

Generally, kids look well at birth but develop these symptoms later:
- Constipation
- Large posterior fontanelle
- Prolonged jaundice
- Macroglossia
- Umbilical hernia
- Feeding difficulties
- Hoarse cry
- Hypotonia

16

When should newborn testing for congenital hypothyroidism occur?

At 2-3 days of age, after the TSH surge

17

There are two tests for congenital hypothyroidism: ________________.

T4: less than 10th percentile
TSH: greater than 20

18

The fetal HPA axis is functional at _____ weeks.

25

19

Thyroid dysgenesis is more common in ____________.

females

20

A baby with spiky hair, micrognathia, cleft palate, and hypertelorism might have a mutation in ________.

TITF-2

21

What is Pendred syndrome?

An autosomal recessive defect in pendrin – which pumps iodide into the colloid – that leads to hypothyroidism, goiter, and sensorineural deafness

22

Central hypothyroidism usually occurs with _____________.

other pituitary defects

Decks in Digestive, Endocrine, and Metabolic Systems Class (133):