Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Block 4 - Endocrine > Clin Lab: Thyroid Disorders > Flashcards

Clin Lab: Thyroid Disorders Flashcards

1
Q

Draw HPA flow of HPA and thyroid gland

A

DONE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Draw the Hypothalamic-Pituitary-Thyroid Axis

A

DONE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which thyroid hormone is higher in the serum?

A

T4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

List the 3 Thyroid Hormones

A
  • Thyroxine (T4)
  • Triiodothyronine (T3)
  • Reverse T3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is T4 activated?

A

T4 is converted to T3 by removal of 1 iodine residue in periph tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

T3 half-life

A

one day

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

T4 half-life

A

one week

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

List the circulation transport proteins for thyroid hormones

A
  • thyroxine-binding globulin (TBG)
  • albumin
  • pre-albumin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

If TSH is high, what could be the causes?

A
  • Thyroid gland is not producing enough T4/T3
    OR
  • Pituitary gland is releasing TSH inappropriately
    OR
  • Very rarely, hypothalamus is releasing TRH inappropriately
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Indications for TSH testing

A
  • initial screening test of thyroid function
  • monitor response to tx
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If initial TSH levels are low or high what is needed?

A

additional testing to determine specific disorder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

If TSH is low, what could be the causes?

A
  • Thyroid gland is making too much T4/T3
    OR
  • Pituitary gland is not making TSH OR
  • Very rarely, hypothalamus is not releasing TRH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What level can help differentiate between primary & secondary causes of abnl TSH?

A

free T4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What helps to TSH levels as we age?

A

it increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Normal range of TSH

A

4-10

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Do you measure TSH in the hospital if someone is ill?

A

NO unless you think the thyroid is causing the illness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What can alter transiently alter TSH levels?

A
  • severe illness
    i.e. sepsis
  • euthyroid sick syndrome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What 3 things can affect TSH levels?

A
  • severe illness
  • pregnancy
  • high dose of biotin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Normal range for FTI

A

1-4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Two main ways to assess FT4

A
  1. Free Thyroxine Index (FTI)
    –> an approximation of FT4 level
  2. Free T4 measurement
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Calculation of FTI

A

FTI (%) = T3 Uptake X Total T4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Is Free T4 high or low in hyperthyroidism?

A

high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Is Free T4 high or low in hypothyroidism?

A

low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Is FT4 harder to measure when levels are high or low?

A

low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why is Free Thyroxine Index (FTI) used?

A

Adjusts for effects of alterations in thyroid-binding PROs on total serum T4

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Is FTI high or low in hyperthyroidism?

A

high

21
Q

Is FTI high or low in hypothyroidism?

A

low

22
Q

Causes of increased Total T4 PROs

A
  • pregnancy
  • OCP
  • hormone replacement therapies
  • some cancers
22
Q

Causes of decreased Total T4 PROs

A
  • testosterone
  • high dose steroids
  • phenytoin
  • salicylates
  • cirrhosis
  • malnutrition
  • nephrotic syndrome
23
Q

When is total T3 used?

A

primarily used as a confirmatory test of hyperthyroidism

24
Q

What to order next if TSH in high?

A

Free T4 OR Total T4/T3 uptake/Free Thyroxine Index

25
Q

When should you check TSH level after a dose adjustment?

A

6 weeks

25
Q

What to order next if TSH in low?

A

Free T4 OR Total T4/T3 uptake/Free Thyroxine Index and Total T3

26
Q

List the autoimmune labs

A

Antithyroglobulin & Antithyroperoxidase Ab
- Anti-TSH receptor Ab

27
Q

If you suspect Hypothyroidism (Hasimoto’s), which test should you order?

A

Antithyroglobulin & Antithyroperoxidase antibodies

28
Q

If you suspect Hyperthyroidism (Graves Dz), which test should you order?

A

Anti-TSH receptor antibodies

29
Q

Indications for thyroid uptake scan

A
  • Thyroid nodule / enlarged thyroid on exam
  • Hyperthyroidism
    when you think cancer
29
Q

Why is it called a “hot” nodule?

A

because the nodule has an increase metabolism & uptakes the tracer more

30
Q

Contraindications of thyroid uptake can

A
  • pregnancy/breast feeding
30
Q

Which type of thyroid nodule is more concerning of cancer?

A

cold nodule

31
Q

Indications for an US w/ biopsy

A
  • Thyroid nodule on exam or on other imaging
  • Assessment of goiter (diffusely enlarged thyroid)
  • Fine needle biopsy guidance
  • Assess lymph nodes surrounding thyroid
  • Preop planning for thyroidectomy
32
Q

S/Sx of hypothyroidism

A
  • cold intolerance,
  • fatigue
  • constipation
  • weight gain
  • thin brittle hair
  • lose lateral eyebrows
  • dry skin
33
Q

Cause of Primary hypothyroidism (95%)

A
  • thyroid doesn’t produce thyroid hormone
  • Most common cause is chronic autoimmune thyroiditis (Hashimoto)
34
Q

Cause of secondary hypothyroidism

A
  • anterior pituitary doesn’t secrete sufficient TSH
  • Most common cause is pituitary adenoma
35
Q

Cause of Tertiary hypothyroidism (RARE)

A
  • hypothalamus doesn’t produce sufficient TRH
36
Q

Initial testing for Hypothyroidism? Expected results?

A

TSH expect it to be high

37
Q

FU testing for hypothyroidism Expected results?

A

Free T4 should be low

38
Q

Optional FU testing for hypothyroidism

A
  • Anti-thyroglobulin (40% of pts) & Anti-thyroid peroxidase antibodies (90% of pts)

+/- imaging

39
Q

Test Results Chart - Hypothyroidism

A

DONE

40
Q

Test Results Chart - Subclinical Hypothyroidism

A

DONE

41
Q

What should be done if pt is asymp + with TSH >10

A

monitor serial labs

42
Q

When should you tx a pt >65 yo?

A

treat if TSH >6.9 (7)

43
Q

When should you tx a pt <65 yo?

A

treat if > upper limit of normal

44
Q

What endocrine condition is associated with increased lipids?

A

hypothyroidism

45
Q

S/Sx of hyperthyroidism

A
  • tachycardia
  • heat intolerance
  • anxiety
  • palpitations
  • Afib
  • tremor
  • sweating
  • warm skin
46
Q

Causes of primary hyperthyroidism

A
  • overproduction of thyroid hormone
    Most common causes:
  • Diffuse Toxic Goiter (Graves’ dz)
  • Toxic Multinodular Goiter (Plummer’s dz)
47
Q

Causes of 2ndary hyperthyroidism

A
  • Overproduction/inappropriate production of TSH by anterior pituitary
  • Most common cause is pituitary adenoma
48
Q

Causes of tertiary hyperthyroidism

A

RARE!!
- Overproduction/inappropriate production of TRH by hypothalamus
- Can be med-induced (amiodarone, lithium)

49
Q

Initial testing for hyperthyroidism & expected results?

A
  • TSH
  • expect it to be low
50
Q

Additional FU testing for hyperthyroidism? & is mostly commonly tested w/ which condition?

A
  • Anti-TSH receptor antibodies (TRAb)
  • Graves Dz
51
Q

FU testing for hyperthyroidism

A
  • free T4
  • total T3
52
Q

Imaging for hyperthyroidism

A
  • thyroid uptake
  • thyroid US
52
Q

Hyperthyroidism Test Results Chart

A

DONE

52
Q

Are there any recommended screening guidelines for thyroid dz?

A

NONE

Block 4 - Endocrine (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions