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Flashcards in Endocrine Deck (29)
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0
Q

What is octreotide?

A

Synthetic drug that mimics somatostatin (inhibits growth hormones). It lasts longer and is rapidly degraded in the body.

1
Q

What is the most abundant pituitary hormone?

A

Growth hormone

2
Q

Growth hormone deficiency can lead to?

A

Dwarfism
Somatotropin can achieve growth caused by low GH production.
But dwarfism cause by lack of GH receptors (Laron dwarfism) or lack of IGF-1 (African pygmies) can not.

3
Q

Excessive growth hormone can lead to?

A

Acromegaly.

Usually caused by a benign pituitary tumour.

4
Q

Features of acromegaly?

A

Enlargement of facial structures, hands and feet.

Increased death rate due to secondary complications such as heart and Lung disease.

5
Q

Treatment of acromegaly?

A
  1. Surgery - 50% success
  2. Somatostatin analogues - octrotide inhibit GF and IGF-1
  3. Growth hormone receptor antagonist - pegvisomant, prevent activation 90% success
  4. Radiotherapy - shrink tumour
  5. Dopamine agonist
6
Q

What are corticosteroids?

A

Steroid hormones secreted by the cortex of the adrenal gland.
2 main types: mineralcorticoids and glucocorticoids

7
Q

What are mineralcorticoids?

A

Regulate water and electrolyte balance.

Principal endogenous mineralcorticoid is aldosterone.

8
Q

What are glucocorticoids?

A

Regulate carbohydrate and protein metabolism.
Principal endogenous glucocorticoid is cortisol.
Some glucocorticoids exert mineralcorticoid activity.

9
Q

Physiological importance of glucocorticoids?

A

Cortisol promotes metabolic changes that allow us to adapt to physiological stresses such as fasting, infections, heat and cold.

10
Q

Pharmacological importance of glucocorticoids?

A

Synthetic glucocorticoids suppress inflammation, allergy and immune responses.

11
Q

What does excess cortisol production cause?

A

Cushing’s disease.
Characterised by - the break down of muscle and redistribution of fat around the body, moon shaped faces, thin fragile skin, easy bruising, muscle weakness, hypertension, buffalo hump, thin arms and legs, increased abdominal fat, poor wound healing.

12
Q

What is the treatment of Cushing’s disease?

A

Surgery - remove tumour
Ketoconazole - inhibit glucocorticoid synthesis
Mifepristone - glucocorticoid receptor antagonist

13
Q

What does deficient cortisol production cause?

A

Addison’s disease.

Characterised by: weight loss, fatigue, muscle pain, joint pain.

14
Q

What is the treatment for Addison’s disease?

A

Replacement therapy.
Physiologic doses of natural glucocorticoids are given daily i. Split doses in order to mimic natural pattern of hormone secretion.

15
Q

When given in supraphysiologic doses, glucocorticoids have what effect?

A

Anti inflammatory and immunosuppressive effects (main use)
Metabolism, water and electrolyte balance and organ systems (unwanted)
Negative feedback systems on hypothalamus/pituitary (unwanted)

16
Q

What are the clinical uses of glucocorticoids?

A

Replacement therapy - low physiologic doses for long periods, minimal side effects
Inhibit inflammation - high doses but given locally, some localised side effects
Inhibit inflammation in allergic reactions - high oral dose but for short period, minimal side effects
Suppress immune system - high oral dose for long periods, significant side effects
Adjunct therapy in cancer - high oral dose used for long period, significant side effects
Stimulate lung development in fetus - high oral dose for short period, minimal side effects

17
Q

What is the glucocorticoid used to inhibit inflammation associated with asthma?

A

Fluticasone.

18
Q

What is a glucocorticoid used to suppress autoimmune diseases?

A

Prednisolone.

19
Q

What glucocorticoid is used to reduce swelling in brain tumours?

A

Dexamethasone.

20
Q

What are some serious side effects of glucocorticoids?

A

Typically arises from prolonged, high dose, oral administration and excesses endogenous production.
Decrease response to infections.
Decrease wound healing.
Decrease capacity to synthesize corticosteroids.
Inhibit growth in children.
Negative feedback effects on hypothalamus + pituitary:
- inhibit secretion of CRF, corticotrophin, cortisol
- exogenous inhibit endogenous which causes atrophy of adrenal gland
- rapid withdrawal can cause acute adrenal insufficiency
- less resistance to stress and infections
-

21
Q

What are combined oral contraceptives?

A

Contraceptive that contains one synthetic oestrogen and one synthetic progestogen component. Most widely used form of contraception.

22
Q

Oestrogens used for combined oral contraceptives?

A

Most commonly: ethinyloestradiol

Less commonly: mestranol

23
Q

Progestogen used in combined oral contraceptives?

A

Most commonly: levonorgestrel, norethisterone

Less commonly: desogestrel, gestodene, cyproterone, dienogest, drospirenone

24
Q

What is the mechanism of action of combined oral contraceptives?

A

Inhibit ovulation
Inhibit fertilisation
Inhibit successful implantation

25
Q

How effective is combined oral contraceptives?

A
99% effective given perfect use.
92% typical use.
Effectiveness is reduced by:
- delayed initiation of the next pill cycle
- hepatic enzyme inducing drugs
26
Q

What are the benefits of combined oral contraceptives?

A

Highly effective, reversible safe contraception.
Prevention of pregnancy related complications
Non-contraceptive benefits:
- decrease risk of ovarian cancer >40%
- decrease risk of endometrial cancer 50%
- decrease risk of benign cancer 30-50%
- improved acne

27
Q

Common adverse effects of combined oral contraceptives?

A
Breakthrough bleeding
Nausea, vomiting
Fluid retention, breast tenderness
Cholasma
Androgenic effects
28
Q

Serious adverse effects of combined oral contraceptives?

A

Enhanced coagulation
- increase risk of myocardial infarction x7 for women with other risk factors
Little or no increase in breast cancer
- tumour tends to be less aggressive
- detected earlier
- small increased risk in younger age group
Small increase in risk for cervical cancer as OC users tend to have increased sexual activity and less protection - HPv