Adrenal Gland (hypo) Flashcards

(60 cards)

1
Q

What is the steroid precursor ?

A

Cholesterol

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2
Q

Which part of the adrenal cortex secretes aldosterone?

A

Zona glomerulosa

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3
Q

Which part of the adrenal cortex secretes cortisol?

A

Zona fasiculata

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4
Q

Which part of the adrenal cortex secretes androgens and oestrogens?

A

Zona reticularis

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5
Q

What is the overall effect of aldosterone?

A
Reduces potassium (Potassium excretion) 
Regulates sodium (sodium reabsorption) 
Maintains blood pressure
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6
Q

What are the four main enzymes involved in aldosterone synthesis within the adrenal cortex?

A

3-hydroxysteroid dehydrogenase
21-hydroxylase
11-hydroxylase
18-hydroxylase

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7
Q

What type of rhythm is exhibited by cortisol secretion?

A

Diurnal rhythm

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8
Q

What is the main cause of Addison’s disease in the UK?

A

Primary adrenocortical failure
(Autoimmune induced destruction of the adrenal cortex)
Atrophy of the adrenal glands.

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9
Q

What is the main cause of Addison’s disease worldwide?

A

Tuberculosis

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10
Q

What are the clinical features of Addison’s disease?

A
Increased pigmentation
Autoimmune vitilgo 
Low blood pressure (syncope)
Weight loss
Fatigue
Hyponatremia, hypoglycaemia, 
Hyperkalaemia
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11
Q

What is the large precursor protein of ACTH?

A

Pro-opio-melanocortin (POMC)

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12
Q

Which peptide is cleaved from POMC subsequently being responsible for hyperpigmentation within patients with Addison’s disaese?

A

alpha-MSH (Melanocortin-stimulating hormone)

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13
Q

Which congenital condition is associated with adrenocortical failure?

A

Congenital adrenal hyperplasia

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14
Q

What are the consequences of adrenocortical failure?

A

1) Fall in blood pressure (hypotension)
2) Loss of salt in the urine (hyponatremia)
3) Increased plasma potassium (hyperkalaemia)
4) Fall in glucose due to glucocorticoid deficiency (Hypoglycaemia)
5) High ACTH resulting in increased pigmentation

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15
Q

Which adrenal hormones are predominantly insufficient in primary adrenocortical failure?

A

Aldosterone and cortisol

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16
Q

Where is pro-opio melanocortin synthesised?

A

Synthesised within the pituitary gland.

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17
Q

What are the peptides that are formed from the cleavage of POMC?

A

ACTH, MSH, endorphins and enkephalins

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18
Q

What clinical investigations are conducted for a patient suspected with Addison’s?

A

9am cortisol = low
ACTH = High
Short synACTHen test to measure the cortisol response (low response)

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19
Q

What is a synACThen test?

A

ACTH is administered to patients through intramuscular injections (250ug), and the cortisol response is measured.

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20
Q

At what time is cortisol level usually elevated?

A

9am

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21
Q

What type of injections are administered during an synACTHen test?

A

Intramuscular injections

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22
Q

What pharmacological treatment is available for primary adrenocortical failure?

A

Fludrocortisone 50-100mg daily

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23
Q

Which atom is added to fludrocortisone?

A

Fluorine

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24
Q

What pharmacodynamic effect does fluorine have in fludrocortisone?

A

Fluorine does not exist in natural steroids, so its presence slows metabolism substantially. Binds to both mineralocorticoid and glucocorticoid receptors.
Has a longer half life (3.5h and effects seen for 18h)

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25
How long are the effects of fludrocortisone seen for?
18 hours
26
Which two receptors are interacted with by fludrocortisone?
MR and GR.
27
What is the half-life for oral hydrocortisone?
Short half-life therefore requires more than once daily administration
28
How often per day is oral hydrocortisone administede?
Thrice daily
29
What is the stereochemical difference between prednisolone and cortisol?
There is an additional double bond, subsequently giving a longer half life and potency in comparison to cortisol.
30
What are the pharmacological advantages of (prednisolone)?
Longer half life More potent that cortisol x2.3 binding affinity
31
Which drug replacement therapy in Addison's disease closely mimics the circadian rhythm?
Prednisolone
32
What three doses are available for prednisolone?
1mg 2.5mg 5mg
33
What is the recommended dose for prednisolone replacement therapy?
2mg-4mg once daily
34
What are the three treatments available for adrenal failure?
Hydrocortisone Prednisolone Fludrocortisone
35
What is the most common enzyme deficiency in congenital adrenal hyperplasia?
21-hydroxylase deficiency
36
Which adrenal hormones are affected in a congenital adrenal hyperplasia?
Aldosterone and cortisol
37
What stage does 21-hydroxylase catalyse in aldosterone synthesis?
Hydroxylation of progesterone to 11-deoxy corticosterone
38
What stage does 21-hydroxylase catalyse in cortisol?
17-OH progesterone to 11-deoxycortisol
39
Which hormones are increased in congenital adrenal hyperplasia?
Sex steroids (androgen production)
40
What are the clinical features for females with congenital adrenal hyperplasia?
``` Labial fusion ambiguous genitalia ambiguous in physical characteristics weight loss vomiting hypotension hyperpigmentation ```
41
How long can a patient survive with diagnosed complete 21-hydroxylase deficiency?
Less than 24 hours
42
What is the age of presentation of complete 21-hydroxylase deficiency?
As a neonate with a salt losing Addisonian crisis Before before (while in utero) foetus gets steroids across placenta. Girls will be born with ambiguous genitalia due to excess testosterone production.
43
Which hormone is concerned with the salt-washing feature of an Addisonian crisis?
Aldosterone
44
Which hormone are deficient in a partial 21-hydroxylase deficiency?
cortisol and aldosterone
45
Which hormones are in excess in a partial 21-hydroxylase deficiency?
Testosterone
46
What is the main difference between a partial 21-hydroxylase deficiency and complete deficiency?
Aldosterone and cortisol is still produced in smaller quantities (responsive to ACTH).
47
What are the main associated symptoms of partial 21-hydroxylase deficiency that present later in life in girls?
Hirsutism and virilisation in girls Male pattern baldness Facial hair Clitomegaly Hyperplastic muscles
48
What are the main associated symptoms of partial 21-hydroxylase deficiency that present later in life in boys?
Precocious puberty in boys due to adrenal testosterone Hyperplastic muscles
49
What stages of aldosterone synthesis is catalysed by 11-hydroxylase?
11-deoxy-corticosterone hydroxylation into corticosterone
50
What stage of cortisol synthesis is catalysed by 11-hydroxylase?
11-deoxycortisol hydroxylation into cortisol.
51
Which aldosterone precursor behaves analogous to aldosterone?
11 deoxycorticosterone
52
In excess, what effects can be caused by 11 deoxycorticosterone?
hypertension and hypokalaemia
53
Which three hormones are in excess in a 11-hydroxylase deficiency?
Sex steroids Testosterone 11-deoxycorticosterone
54
What are the problems associated with a 11-hydroxylase deficiency?
Virilisation Hypertension Hypokalaemia (due to elevations in 11-deoxycorticosterone)
55
What stage is catalysed by 17-hydroxylase?
Progesterone hydroxylation into 17-OH-progesterone.
56
Which hormones are deficient in a 17-hydroxylase deficiency?
Cortisol | Sex steroids
57
Which hormones are in excess in a 17-hydroxylase deficiency?
Aldosterone | 11-deoxycorticosterone
58
What are the associated problems with a 17-hydroxylase deficiency?
Hypertension Hypokaleia Sex steroid deficiency glucocorticoid deficiency (hypoglycaemia)
59
What is the equivalent dose for an intermediate acting prednisolone?
3mg
60
What is the relative glucocoritcoid potency for prednisolone?
x7