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RR ENDO > Therapeutic use of adrenal steroids > Flashcards

Therapeutic use of adrenal steroids Flashcards

1
Q

Mineralacorticoid e.g
Glucocorticoid e.g

Which receptor selects for both?

What does the zona glomerulosa produce?

A

Mineralacoirticoid- Aldosterone
Glucocorticoid- Cortisol

MR selective for both

Aldosterone–GA

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2
Q

What does the zona fasciculata produce?

A

Cortisol FC

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3
Q

What does the zona reticular produce?

A

Androgens and oestrogens OR

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4
Q

Which hormones are under the control of ACTH?

A

Cortisol and androgens

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5
Q

What stimulates aldosterone release?

A

Renin-angiotensin system

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6
Q

Where is renin produced?

A

Juxtaglomerular cells

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7
Q

What does renin do?

A

Converts angiotensinogen to angiotensin I

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8
Q

What does ACE do?

Where is this produced

A

Converse angiotensin I to angiotensin II

Lungs

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9
Q

What does angiotensin II do?

A

Stimulates release of aldosterone from adrenal cortex

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10
Q

What triggers Beta-1 adrenoceptor stimulation

what does this result in

A

Hyperkalaemia
Hyponatraemia
Drop in renal blood flow
Beta-1 adrenoceptor stimulation

release of aldosterone

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11
Q

Which adrenal steroid is essential for life?

A

Cortisol

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12
Q

Why are the principle physiological actions of adrenal androgens unknown?

A

Gonads are a much bigger source of androgens

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13
Q

What are the difference between glucocorticoid and mineralocorticoid receptors?

A

Glucocorticoid:
Wide distribution
Selective for glucocorticoids
Low affinity for cortisol

Mineralocorticoid:
Discrete distribution -kidney
Don’t distinguish between aldosterone and cortisol
High affinity for cortisol

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14
Q

Why is MRs lack of selectivity a problem?

A

Cortisol can stimulate them

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15
Q

How are MRs protected from cortisol?

A

Cortisol is converted to cortisone by 11beta hydroxysteroid dehydrogenase

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16
Q

Why do you have hypokalaemia in Cushing’s?

A

The system gets overwhelmed, when there is lots of cortisol, 11 betahydroxysteroid dehydrogenase is oversaturated , so some binds to mineralocorticoid receptors and causes hypokalaemia

17
Q

How does cortisol compare to hydrocortisone?

A

They have the same structure but hydrocortisone is synthetic and cortisol is endogenous– also is a glucocorticoid with mineralocorticoid activity at high doses

18
Q

What sort of steroid is prednisolone?

A

glucocorticoid with weak mineralocorticoid activity

19
Q

What sort of steroid is dexamethasone?

A

synthetic glucocorticoid with no mineralocorticoid activity

20
Q

What sort of steroid is fludrocortisone?

A

Aldosterone analogue– used as aldosterone substitute

21
Q

How are these corticosteroids administered

A

Oral:
Hydrocortisone, Prednisolone, Dexamethasone, fludrocortisone

Pareteral – i.v or i.m
Hydrocortisone, dexamethasone

22
Q

Which plasma proteins do corticosteroids bind to?

A

Corticosteroid binding globulin and albumin

23
Q

In terms of binding, how do the other corticosteroids (prednisolone, dexamethasone and fludrocortisone) compare?

A

They are less bound and fludrocortisone is only bound to albumin

24
Q

What is the order of the corticosteroids from shortest to longest half life?

A

Hydrocortisone 8
Prednisolone 12
Dexamethasone 40 hrs

25
Q

What are reasons for giving replacement corticosteroid?

A

Primary adrenocortical failure
Secondary adrenocortical failure
Acute adrenocortical failure
Congenital adrenal hyperplasia

26
Q

What is the main causes of primary adrenocortical failure?

Acute adrenocortical failure

A

Addison’s disease

Addisonian crisis

27
Q

What is wrong in primary adrenocortical failure?

A

Their adrenal cortex just isn’t working, they can’t make any hormones and need replacement cortisol and aldosterone

28
Q

Why do primary adrenocortical failure patients not need replacement androgens?

A

The loss of production from adrenal cortex isn’t a big deal because most androgens are made in gonads

29
Q

How is primary adrenocortical failure treated?

A

Hydrocortisone and fludrocortisone
Fludrocortisone is adminstered first by mouth and then hydrocortisone so that the MR is protected from the hydrocortisone

30
Q

What is wrong in secondary adrenocortical failure?

A

Lack of ACTH- problem in adenohypophysis

31
Q

What is the difference between a patient with primary and secondary adrenocortical failure?

A

Secondary have aldosterone because RAS works properly

both dont have cortisol

32
Q

How do you treat secondary adrenocortical failure?

A

Hydrocortisone

33
Q

What is there a lack of in congenital adrenal hyperplasia?

A

Enzymes required for adrenal steroid synthesis

34
Q

What are most cases of congenital adrenal hyperplasia due to? What does this result inn

A

Lack of 21-hydroxylase

Build up in 3rd pathway-androgens due increased ACTH due to negative feedbacl
-hirsutism and virilisation
Build up in 17 a hydroxyporgesterone – immediately before enzyme block

35
Q

How do you treat congenital adrenal hyperplasia?

A

Replace cortisol:
Dexamethasone 1/day or hydrocortisone 2-3/day
SUPPRESS ACTH and thus adrenal androgen production
Replace aldosterone- fludrocortisone
Monitor optimise therapy by measuring 17alpha-hydroxyprogesterone
Do a clinical assessment of what they are complaining about:
Cushingoid- too much glucocorticoid
Hirsutism/acne- too little glucocorticoid (high ACTH)

36
Q

What is the normal cortisol production?

A

20mg/day

37
Q

When to increase glucocorticoid dosage

A

In minor illness 2x

Surgery- hydrocortisone i.m , with pre-med then orally.

38
Q

Why does iatrogenic adrenocortical failure occur?

A

If they’re on glucocorticoids for a long term, they will stop producing cortisol as they don’t need to anymore

39
Q

Acute adrenocortical failure treatment

A
  • i.v NaCl.
  • High dose hydrocortisone i.v or i.m
  • Dextrose if hypoglycaemic due to increased cortisol reach uses up blood glucose

RR ENDO (13 decks)

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