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Y2 Endocrinology > Therapeutic use of adrenal steroids > Flashcards

Therapeutic use of adrenal steroids Flashcards

1
Q

What stimulates the RAAS

A

Hyperkaelaemia
Hyponatraemia
Reduced renal blood flow
beta1-adrenoceptor stimulation

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2
Q

Draw a diagram showing the control of adrenal steroid production

A
  1. Circadian stimuli/stress causes CRH release from the hypothalamus
  2. ACTH release from the anterior pituitary gland
  3. zona reticularis -> androgens, oestrogens
    zona fasciculata ->cortisol
    zona glomerulosa -> aldosterone
  4. angiotensinogen (liver) converted to angiotensin I by renin (kidney)
  5. angiotensin I converted to angiotensin II by ACE
  6. Stimulates aldosterone release
  7. -ve feedback to hypothalamus and anterior pituitary via cortisol
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3
Q

What are the principal actions of adrenal steroids

A

Cortisol - essential for life

Aldosterone - promotes sodium retention and potassium lost

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4
Q

What are the receptors for corticosteroids

A 
Glucocorticoid receptors (GR)
Mineralocorticoid receptors (MR)
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5
Q

Describe glucocorticoid receptors

A

Wide distribution
Selective for glucocorticoids
Low affinity for cholesterol

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6
Q

Describe mineralocorticoid receptors

A 
Discrete distribution (kidney )
Does not distinguish between aldosterone and cortisol 
High affinity for cortisol
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7
Q

How are mineralocorticoid receptors protected from cortisol

A

Cortisol is converted to inactive cortisone by 11beta-hydroxysteroid dehydrogenase 2 (11b-hsd)

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8
Q

What is the receptor selectivity of hydrocortisone

A

Glucocorticoid with mineralocorticoid at high doses

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9
Q

What is the receptor selectivity of prednisolone

A

Glucocorticoid with weak mineralocorticoid activity

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10
Q

What is the receptor selectivity of dexamethasone

A

Synthetic glucocorticoid with no mineralocorticoid activity

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11
Q

What is fludrocortisone

A

Aldosterone analogue used as an aldosterone substitute

-> Mineralocorticoid

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12
Q

Draw the structures of hydrocortisone, prednisolone, fludrocortisone and dexamethasone

A

-

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13
Q

What are the routes of administration for hydrocortisone, prednisolone, dexamethasone and fludrocortisone

A

Oral - hydrocortisone, prednisolone, dexamethasone, fludrocortisone

Parenteral - hydrocortisone, dexamethasone

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14
Q

How do corticosteroids distribute pharmacokinetically

A

Binds to plasma proteins - cortisol binding globulin (CBG) and albumin

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15
Q

What are the duration of action times for hydrocortisone, prednisolone and dexamethasone

A

Hydrocortisone - 8h
Prednisolone - 12h
Dexamethasone - 40h

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16
Q

What is the treatment for Addison’s disease

A

Corticosteroid replacement therapy - patients lack cortisol and aldosterone
Hydrocortisone and fludrocortisone orally

17
Q

What is the treatment for secondary adrenocortical failure

A

Corticosteroid replacement therapy - ACTH failure so patients lack cortisol
Hydrocortisone

18
Q

What is the treatment for acute adrenocortical failure/addisonian crisis

A

0.9% sodium chloride IV (rehydrate patient)
High dose hydrocortisone via IV infusion or IM every 6 hours
5% dextrose if hypoglycaemia

19
Q

Why can hydrocortisone be used for addisonian crisis

A

Acts as a mineralocorticoid at high doses as it overwhelms 11beta-hydroxysteroid dehydrogenase

20
Q

How is congenital adrenal hyperplasia (CAH) treated

A

Corticosteroid replacement therapy - congenital lack of enzymes needed for adrenal steroid synthesis
Fludrocortisone
dexamethasone once a day in the pm
or
Hydrocortisone 2-3 times a day. high dose, pm

21
Q

What are the objectives of CAH therapy

A

Replace cortisol
Suppress ACTH and adrenal androgen production
Replace aldosterone in salt washing forms

22
Q

How is treatment for CAH monitored and optimised

A

17-OH progesterone
Clinical assessment:
Cushingoid - GC dose too high
Hirsutism - GC dose too low (so ACTH has risen)

23
Q

What adjustments have to be made for patients being treated for adrenocortical failure

A

normal cortisol production (20mg/day)
in stress production (200-300mg/day)

Increase glucocorticoid dosage when patients are vulnerable to stress

24
Q

When do you increase glucocorticoid dosage

A

Minor illness - 2x normal dose

Surgery - hydrocortisone IM with pre-med and at 6-8 hour intervals, oral once eating and drinking

25
Q

What is important to tell patients with adrenocortical failure

A

Carry a steroid alert card and wear a medic alert bracelet/necklace

26
Q

What are the measurements taken for congenital adrenal hyperplasia

A

17 alpha - hydroxyprogesterone as it increases before the enzyme block of 21-hydroxylase

27
Q

Why does sex steroid production increase in congenital adrenal hyperplasia

A

21-hydroxylase deficiency - no cortisol production and ACTH rises (no -ve feedback) High ACTH drives further adrenal androgen production

Y2 Endocrinology (19 decks)

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