360 - Hormones Flashcards

1
Q

most common hormone tests performed in core

A

hCG and thyroid

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

how can hormones be measured?

A

several techniques, including immunoassay and instrumental techniques such as GC-MS

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

how can hormones be measured?

A

several techniques, including immunoassay and instrumental techniques such as GC-MS

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

sample collection or hormone assay considerations

A
  • nutrition
  • diurnal variation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

serum iodide is trapped in the ________, and iodine is incorporated into ___________.

A

thyroid; tyrosine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

this is key to the synthesis of the thyroid hormones

A

iodine
- rate-limiting step is the iodine transport to the follicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

the process of thyroid hormones being released

A
  • TRH from hypothalamus secreted due to low thyroid hormone concentrations
  • TRH interacts w anterior pit gland = TSH
  • TSH binds to thyroid follicular cells = T3 and T4, and reverse T3
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

the major secretory product of the thyroid

A

T4
30X higher in plasma than T3
Both free and bound hormones are found in circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

T3 and T4 transported in blood by this

A

TBG; thyroid binding globulin
transthyretin
albumin

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

This binding protein has the greatest affinity for T4

A

TBG
also the most important in regulating free T4 concentration

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

In the ________, free T4 is deiodinated to create biologically active ___.

A

liver; T3

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

what does T3 do?

A

regulates the rate of cellular oxidation and metabolism

T3 helps regulate cellular uptake of glucose and influences protein metabolism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

T or F. Increased thyroid hormone concentrations inhibit the pituitary response to TRH

A

T!

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

T or F. An increase in thyroid hormone concentrations will cause an increase in TRH and TSH secretion

A

F! Decrease in thyroid hormone…

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Graves’ disease

A

characterized by the formation of autoantibodies specific to the TSH receptor

The autoantibodies stimulate the receptor leading to hyperthyroidism

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

Hashimoto thyroiditis

A

characterized by cell-mediated autoimmunity, causing thyroid dysfunction

clinical presentation includes goitre, thyroiditis, and frequently hypothyroidism

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

hypothyroidism

A

general term for thyroid hormone deficiency or lack of response to thyroid hormone

18
Q

primary hypothyroidism

A
  • endogenous or exogenous
  • most common cause of endogenous hypothyroidism is autoimmune thyroid disease (e.g. Hashimoto thyroiditis)
  • Exogenous hypothyroidism is associated with iodine excess or deficiency and various medications
19
Q

secondary hypothyroidism

A

the result of damage/disease of the hypothalamus or pituitary gland

20
Q

a condition characterized by excess production of thyroid hormones resulting in hypermetabolism

A

hyperthyroidism
- endogenous vs exogenous

21
Q

Endogenous causes of hyperthyroidism

A

Graves’ disease
thyroid tumours
disorders of the hypothalamus or pituitary gland

22
Q

Exogenous hyperthyroidism

A

associated w viral and bacterial thyroiditis

23
Q

Non-thyroidal illness (NTI)

A

presents w low total and free T3, elevated reverse T3, and normal to low TSH in the absence of true thyroid disease

24
Q

NTI is seen in…

A

starvation,
sepsis,
surgery,
myocardial infarction,
diabetes,
many other severe illnesses

25
Q

NTI underlying problem

A

lack of conversion of T4 to T3 at the tissue = appears to be multifactorial and includes …

suppression of TRH release,
reduced T3 and T4 turnover,
reduction in liver generation of T3,
increased the formation of rT3,
tissue-specific down-regulation of receptors, transporters, and enzymes

26
Q

Progressive testing protocol for thyroid function testing

A

progressive testing with TSH as the primary screening test
TSH is the most sensitive and specific test for the investigation and management of primary thyroid dysfunction.

TSH (in comparison to total T4 or free T4) is not as markedly affected by physiologic alterations resulting from severe non-thyroidal sickness or by the administration of therapeutic drugs

27
Q

hCG

A

a glycoprotein molecule (hormone) produced by the placent
- has two subunits: alpha and a beta chain
β subunit is specific to hCG
α subunit is also found in TSH, LH, and FSH

28
Q

hCG acts on the ____________ _________.

A

corpus luteum = produces progesterone until the placenta can produce enough progesterone to maintain the pregnancy

Progesterone prevents menses

29
Q

qualitative hCG in the urine can be used to diagnose…

A

pregnancy (as early as eight days after fertilization)

30
Q

Quantitative levels of serum or plasma hCG can be used to:

A

date pregnancy
detect multiple pregnancies (2X normal level with twins)
assist in the detection of ectopic pregnancy

31
Q

Increased intact hCG and free β subunit can be observed in:

A

trophoblastic disease (choriocarcinoma, hydatiform mole) germ cell tumours (primarily tumours of the testis, ovaries)
other cancers (biliary, pancreatic)

32
Q

Serial measurement of hCG is used to monitor treatment and progression of…

A

trophoblastic disease

33
Q

When using hCG as a tumour marker one should measure both of these

A

intact hCg and free B subunits

34
Q

Prenatal screening is used to determine the risk of having a fetus with serious birth defects such as…

A

neural tube defect or Down’s syndrome

35
Q

The first trimester screen is performed between…

A

10 and 13 weeks gestation

36
Q

first trimester screening

A
  • 10 to 13 wks
  • blood is quantitatively tested for hCG and the pregnancy associated plasma protein A (PAPP-A) NOTE: HCG and PAPP-A are produced by the placenta
  • Down’s syndrome PAPP-A is relatively low while HCG is relatively high
  • these are interpreted in conjunction with a nuchal translucency test; increased nuchal space is associated with Down’s syndrome
37
Q

nuchal translucency test

A

In the nuchal translucency test, the subcutaneous space between the skin and cervical spine of the fetus is measured

38
Q

a prenatal test that measures levels of four substances in a pregnant woman’s blood to estimate the risk of open spina bifida, anencephaly, trisomy 21, and trisomy 18

A

MoM (Multiples of the Median) or Quad screen

second trimester

39
Q

substances measured in MoM

A
  • Alpha-fetoprotein (AFP), a protein made by the developing baby
  • Human chorionic gonadotropin (hCG), a hormone made by the placenta
  • Unconjugated estriol 3, a hormone made by the placenta and the baby’s liver
  • Dimeric Inhibin A, another hormone made by the placenta
40
Q

Multiple of the median is a statistical value that measures…

A

how different a patient result is from the median result of a similar population

it’s used in situations where individual test results are highly variable (such as in pregnancy) and are typically used for screening purposes

MoM results greater than cutoff value = additional testing

NOTE: cut off value does not have a 100% positive or negative predictive value