Disorders of Adenocorticol Function Flashcards Preview

Z OLD ESA 1- Metabolism > Disorders of Adenocorticol Function > Flashcards

Flashcards in Disorders of Adenocorticol Function Deck (76):
1

What is characterised by decreased activity of the adrenal cortex?

Addisons disease

2

What may Addison's disease be due to?

#NAME?

3

What can cause disease of the adrenal cortex?

Autoimmune destruction

4

What is the result of reduction in activity of the adrenal cortex?

Reduces glucocorticoids and mineralocorticoid secretion

5

What do disorders of the pituitary and hypothalamus leading to decreased secretion of ACTH affect?

Glucocorticoids only

6

What is characterised by increased secretion of glucocorticoids?

Cushing’s syndrome

7

What may Cushing’s syndrome be due to?

- Increased activity of the adrenal cortex due to tumour (adenoma) 
- Disorders in secretion of ACTH caused by pituitary adenoma
- Ectopic secretion of ACTH

8

What is the disease caused by pituitary adenoma causing increased ACTH secretion?

Cushing’s disease

9

What is congenital adrenal hyperplasia?

A number of clinical conditions that arise as a consequence of a genetic defect in one or more of the enzymes required for synthesis of cortisol

10

What happens due to the lack of cortisol in congenital adrenal hyperplasia?

The pituitary is not subjected to negative feedback control

11

What is the result of the pituitary not being subject to negative feedback?

It secretes large amounts of ACTH

12

What does excess ACTH secretion in congenital adrenal hyperplasia’s cause?

An enlargement of the adrenal cortex (hyperplasia)

13

What does the severity of the consequences of congenital adrenal hyperplasias depend on?

Which enzyme(s) is affected

14

What are the effects of excess cortisol secretion?

- Increased muscle proteolysis and hepatic gluconeogenesis 
- Increased lipogenesis in adipose tissue 
- Purple striae on lower abdomen, upper arms and thighs 
- Immuno-suppressive, anti-inflammatory and anti-allergic reactions of cortisol 
- Back pain and collapse of ribs 
- Hypertension

15

What can increased muscle proteolysis and hepatic gluconeogenesis lead to?

Hyperglycaemia, and associated polyuria and polydipsia

16

What is hyperglycaemia due to excess cortisol secretion called?

Steroid diabetes

17

What does increased muscle proteolysis cause?

Wasting of proximal muscle

18

What is the result of proximal muscle wastage?

#NAME?

19

What does the increased lipogenesis in adipose tissue on excess cortisol secretion lead to?

Deposition of fate in abdomen, neck and face

20

What does the deposition of fat in excess cortisol secretion lead to?

The characteristic body shape, moon-shaped face and weight gain

21

What do the purple striae caused by excess cortisol secretion reflect?

The catabolic effects of protein structures in skin

22

What does the decreased protein integrity in skin caused by excess cortisol secretion lead to?

Easy bruising

23

Why does excess cortisol secretion lead to easy bruising?

Because there is thinning of the skin and subcutaneous tissue

24

What does the immunological effects of excess cortisol secretion lead to?

Increased susceptibility to bacterial infections, anda cne

25

Why may excess cortisol secretion cause back pain and rib collapse?

Due to osteoporosis

26

Why does excess cortisol production lead to osteoporosis?

Because of disturbances to calcium metabolism, and loss of bone matrix proteins

27

Why may mineralocorticoid effects of excess cortisol lead to hypertension?

Due to sodium and fluid retention

28

Where else may the symptoms of excess cortisol secretion occur?

In patients receiving long-term treatment with glucocorticoids for various chronic conditions

29

What would autoimmune destruction of the adrenal gland?

Involve loss of cortisol and mineralocorticoids

30

How does the loss of cortisol and mineralocorticoids present?

It is a complex situation, that may present as an acute emergency (Addisonian Crisis), or as a chronic debilitating disorder (Addison’s disease)

31

How does Addison’s disease onset?

Insidious onset, with initial non-specific symptoms of tiredness, extreme muscular weakness, anorexia, vague abdominal pain, weight loss and occasional dizziness

32

What symptoms of Addison’s disease are extreme?

The muscular weakness and dehydration

33

What is a more specific sign of Addison’s disease?

Increased pigmentation

34

Where does increased pigmentation occur especially in Addison’s disease?

- Exposed areas of the body 
- Points of friction 
- Buccal mucosa 
- Scars 
- Palmar creases

35

Why does Addison’s disease cause increased pigmentation?

Due to ACTH-mediated melanocyte stimulation

36

What happens to blood pressure in Addison’s disease?

It decreases

37

Why does Addison’s disease decrease blood pressure?

Due to sodium and fluid depletion

38

What causes postural hypotension in Addison’s disease?

Fluid depletion

39

What kind of episodes does Addison’s disease cause?

Hypoglycamic

40

When do the hypoglycaemic episodes caused by Addisons disease particularly occur?

On fasting

41

What can exacerbate the effects of Addison’s disease?

Stress, such as trauma of severe infection

42

What can the exacerbation of the symptoms of Addison’s disease with stress cause?

- Nausea
- Vomiting
- Extreme dehydration
- Hypotension 
- Confusion 
- Fever
- Coma

43

What is the exacerbation of the symptoms of Addison’s disease with stress called?

An Addisonian crisis

44

What does an Addisonian crisis constitute?

A clinical emergency

45

How is an Addisonian crisis treated?

IV cortisol and fluid replacement

46

How is adrenocortisol function measured clinically?

- Plasma cortisol 
- ACTH levels 
- 24hr urinary secretion of cortisol and its breakdown products 
- Dynamic function tests

47

What are the breakdown products of cortisol?

17-hydroxysteroids

48

Give 2 examples of dynamic function tests

- Dexomethasone surpression tests 
- ACTH stimulation tests

49

What can clinical tests of adrenocortisol function be used in?

Differential diagnosis of adrenocortisol disease

50

What is dexamethasone?

A potent steroid

51

What would normally happen when dexamethasone is given orally?

Would suppress the secretion of ACTH and therefore cortisol

52

How does dexamethasone suppress?

Feedback inhibition

53

What dexamethasone suppression of plasma cortisol is characteristic of Cushing’s disease?

>50%

54

Why is a dexamethasone suppression of >50% characteristic of Cushing’s disease?

Because for the diseases pituitary, even though its relatively insensitive to cortisol, it does retain some sensitivity to potent synthetic steroids

55

Where does dexamethasone suppression not normally occur?

In adrenal tumours or ectopic ACTH production

56

What is the result of dexamethasone suppression not normally occurring in adrenal tumours or ectopic ACTH production mean?

Rules them out, suggesting the result is due to a pituitary tumour

57

What is Synacthen?

A synthetic analogue of ACTH

58

What does the intramuscular administration of Synacthen normally cause?

An increase in plasma cortisol by >200nmol/L

59

What does a normal response to Synacthen achieve?

The exclusion of Addison’s disease

60

What do the steroid receptors form?

Part of a family of nuclear DNA-binding proteins

61

What does the family of nuclear DNA-binding proteins formed by steroid receptors include?

The thyroid and vitamin D receptors

62

What do all steroid receptors have?

3 main regions

63

What are the 3 main regions of a steroid receptor?

- A hydrophobic hormone-binding region 
- A DNA binding region 
- A variable region

64

What is the DNA binding region of a steroid receptor rich in?

Cysteine and basic amino acids

65

What exists in the hormone binding regions of steroid receptors?

Sequence homology

66

What is the % homology of the hormone bind region of the glucocorticoid receptor with the mineralocorticoid receptor?

64%

67

What is the % homology of the hormone bind region of the glucocorticoid receptor with the androgen receptor?

62%

68

What is the % homology of the hormone bind region of the glucocorticoid receptor with the oestrogen receptor?

31%

69

What is the % homology of the hormone bind region of the glucocorticoid receptor with the thyroid receptor?

24%

70

What is the result of the sequence homology of steroid receptors?

Cortisol will bind to the mineralocorticoid and androgen receptors with low affinity

71

When may cortisol binding to mineralocorticoid and androgen receptors be significant?

When high levels of hormone present

72

What does aldosterone do?

- Stimulates Na + reabsorption in exchange for K + (or H + )
- Stimulates growth and development of male genital tract and male secondary sexual characteristics, including height, body shape, facial and body hair, lower voice pitch
- Anabolic effects on muscle protein

73

What does over-secretion of aldosterone cause?

- Increases Na +  and water retention 
- Loss of K +
- In females- 
- Hair growth (hirsutism)
- Acne
- Menstrual problems
- Virilisation
- Increased muscle bulk 
- Deepening voice

74

What does an increased Na +  and water retention, and loss of K + cause?

Hypertension and muscle weakness

75

What does under secretion of aldosterone cause?

Hypotension

76

What does oestrogen do?

- Stimulates growth and development of female genital tract, breasts and female secondary characteristics, including broad hips, accumulation of fat in breasts and buttocks, body hair distribution 
- Weakly anabolic 
- Decrease circulating cholesterol levels