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Z YEAR 2 BRS ENDO > Adrenal Glands > Flashcards

Adrenal Glands Flashcards

1
Q

Where do steroids come from?

A

Cholesterol

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2
Q

What does the adrenal cortex produce?

A

Corticosteroids

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3
Q

What are the 3 groups of corticosteroids?

A
  1. Mineralcorticoids
  2. Glucocorticoids
  3. Sex steroids
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4
Q

What is an example of mineralcorticoids?

A

Aldosterone

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5
Q

What is an example of glucocorticoids?

A

Cortisol

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6
Q

What is an example of sex steroids?

A

Adrogens, oestrogen

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7
Q

What does angiotensin II do on the adrenals?

A
  • Activation of the following enzymes
  • Side Chain Cleavage
    1. 3 Hydroxysteroid dehydrogenase
    2. 21 hydroxylase
    3. 11 hydroxylase
    4. 18 hydroxylase
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8
Q

How does aldosterone act?

A

Controls blood pressure, sodium and lowers potassium

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9
Q

What effect does ACTH have on the adrenals?

A
  • Activation of the following enzymes
  • Side Chain Cleavage
    1. 3 Hydroxysteroid dehydrogenase
    2. 21 hydroxylase
    3. 11 hydroxylase
    4. 17 hydroxylase (not 18)
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10
Q

What is an enzyme?

A
  1. Protein that catalyses a specific reaction
  2. Various enzymes are present in cells
  3. Specific enzymes catalyse the synthesis of particular alterations to the molecule
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11
Q

What is the action of cortisol?

A

diurnal

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12
Q

What is Addison’s disease?

A
  1. Primary adrenal failure

2. Autoimmune disease where the immune system decides to destroy the adrenal cortex (UK)

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13
Q

What is the commonest cause of Addison’s?

A

Tuberculosis of the adrenal glands

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14
Q

What does the pituitary do in Addisons?

A

Secretes lots of ACTH and hence MSH

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15
Q

What are the symptoms of Addisons?

A
  1. Increased pigmentation
  2. Autoimmune vitiligo may coexist
  3. Freckling
  4. Darkening of hair
  5. Loss of weight
  6. Low BP
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16
Q

Why is there low BP in Addisons?

A

No cortisol or aldosterone

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17
Q

Why do you have a tan in Addisons?

A
  1. POMC is a large precursor protein that is cleaved to form a number of smaller peptides, including ACTH, MSH and endorphins
  2. Thus people who have pathologically high levels of ACTH may become tanned
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18
Q

What happens in an adrenal crisis?

A
  1. Fever
  2. Syncope
  3. Convulsions
  4. Hypoglycaemia
  5. Hypoatremia
  6. Severe vomiting and diarrhea
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19
Q

What are the causes of adrenocortical failure?

A
  • Adrenal glands destroyed (2)
  • Enzymes in the steroid synthetic pathway not working (1)
    3. Tuberculous Addison’s disease (commonest worldwide)
    4. Autoimmune Addison’s disease (commonest in UK)
    5. Congenital adrenal hyperplasia
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20
Q

What are the consequences of adrenocortical failure?

A
  1. Fall in blood pressure
  2. Loss of salt in the urine
  3. Increased plasma potassium
  4. Fall in glucose due to glucocorticoid deficiency
  5. High ACTH resulting in increased pigmentation (why ?)
  6. Eventual death due to severe hypotension
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21
Q

What is POMC?

A

pro-opio melanocortin

22
Q

Where is POMC synthesised and broken down in to what?

A
  1. Synthesised in pituitary
  2. Broken down to ACTH and MSH and endorphins and enkephalins and other peptides
    - No negative feedback so ACTH increased as cortisol absent or low and in the process of increased ACTH, lots of MSH stimulate pigmentation but cortex is gone
23
Q

What is the test for Addison’s with cortisol and ACTH?

A
  • 9am cortisol = low

* ACTH = high

24
Q

What test do you give and measure in Addison’s?

A
  • Short synACTHen test
  • Give 250 ug synacthen IM
  • Measure cortisol response
25
Q

What are the results for a typical Addison’s patient?

A
  1. Cortisol at 9am = 100 (270-900)
  2. Administer injection IM of synacthen
  3. Cortisol at 9.30 = 150 (>600)nM (if normal should rise to 600)
26
Q

Why do you not give aldosterone in Addison’s?

A

Half life of aldosterone is too short for safe once daily administration

27
Q

Why do you give Fludrocortisone?

A
  1. Add fluorine to steroid becomes long lasting
  2. does not exist in natural steroids, so its presence slows metabolism substantially
  3. Binds to both MR and GR
  4. Fludrocortisone half life 3.5h and
    effects seen for 18h.
28
Q

What dose of fludrocortisone is given?

A

50-100mcg daily

29
Q

Why do you not give oral hydrocortisone?

A
  • short half life: too short for once daily administration - so give 3 times a day 10,5 then 2.5
  • Two later peaks too high / harmful
30
Q

Why do you give prednisolone?

A
  • longer half life and is more potent than cortisol

- 2.3x binding affinity than cortisol

31
Q

What dose do you give of prednisolone?

A

Replacement dose 3-4mg ONCE daily

32
Q

Why is the dose of prednisolone different? How much hydrocortisone is it?

A

•2mg-4mg once daily

  • We need more research to define the correct dose for each patient.
  • This would be an equivalent dose of 15-25mg hydrocortisone daily.
33
Q

What medicine do you use to treat adrenal failure?

A
  1. Hydrocortisone three times daily (10 + 5 + 2.5)
  2. Prednisolone 3mg daily
  3. Fludrocortisone 50 to 100 mcg daily
34
Q

What is the commonest cause of congenital adrenal hyperplasia?

A

21-hydroxylase deficiency (circulating cortisol is low, as although some from mum none themselves and so high ACTH so adrenal gland grow and grows)

35
Q

Which hormones are totally absent in complete 21-hydroxylase deficiency?

A

aldosterone and cortisol

36
Q

How long do you survive in complete 21 hydroxylase deficiency?

A

Less than 24 hours (but if spotted give hydrocortisone)

37
Q

Which hormones are in excess in complete 21 hydroxylase deficiency?

A

Sex steroids and testosterone

38
Q

What is the age of presentation in complete 21 hydroxylase deficiency?

A
  1. Neonate: Salt losing Addison’s crisis
  2. Before birth: ok as gets steroids across placenta
  3. Girls might have ambiguous genitalia (virilised by adrenal testo) - as adrenals makes to much sext steroid which they shouldn’t
39
Q

Which hormones are deficient in partial 21 hydroxylase deficiency?

A

cortisol and aldosterone

40
Q

Which hormones are in excess in partial 21 hydroxylase deficiency?

A

Sex steroids and testosterone

41
Q

What age do people with partial 21 hydroxylase deficiency present?

A

Any age as they survive

42
Q

What is the main problem in partial 21 hydroxylase deficiency?

A
  1. hirsutism and virilisation in girls

2. precocious puberty in boys due to adrenal testosterone

43
Q

What does 11 deoxycorticosterone behave like?

A

aldosterone

44
Q

What happens in excess 11 deoxycorticosterone deficeincy?

A

hypertension and hypokalaemia

45
Q

Which hormones are deficient in 11 deoxycorticosterone deficiency?

A

Cortisol and aldosterone

46
Q

Which hormones are in excess in 11 deoxycorticosterone deficiency?

A
  1. Sex steroids
  2. testosterone
  3. 11-deoxycorticosterone
47
Q

What problems can you have with 11 deoxycorticosterone deficiency?

A
  1. Virilisation
  2. hypertension
  3. low K
48
Q

Which hormones are deficient in 17 hydroxylase deficiency?

A

Cortisol and sex steroids

49
Q

Which hormones are in excess in 17 hydroxylase deficiency?

A

11-deoxycorticosterone and aldosterone (mineralocorticoids)

50
Q

What are the problems in 17 hydroxylase deficiency

A
  1. Hypertension
  2. low K
  3. sex steroid deficiency
  4. glucocorticoid deficiency (low glucose).
51
Q

What does of prednisolone available?

A

1mg, 2.5mg, 5mg - not enteric coated which slows absorption

Z YEAR 2 BRS ENDO (13 decks)

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