Endocrine

Question 0

What is octreotide?

Answer 0

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

Question 1

What is the most abundant pituitary hormone?

Answer 1

Growth hormone

Question 2

Growth hormone deficiency can lead to?

Answer 2

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.

Question 3

Excessive growth hormone can lead to?

Answer 3

Acromegaly.

Usually caused by a benign pituitary tumour.

Question 4

Features of acromegaly?

Answer 4

Enlargement of facial structures, hands and feet.

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

Question 5

Treatment of acromegaly?

Answer 5

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

Question 6

What are corticosteroids?

Answer 6

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

Question 7

What are mineralcorticoids?

Answer 7

Regulate water and electrolyte balance.

Principal endogenous mineralcorticoid is aldosterone.

Question 8

What are glucocorticoids?

Answer 8

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

Question 9

Physiological importance of glucocorticoids?

Answer 9

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

Question 10

Pharmacological importance of glucocorticoids?

Answer 10

Synthetic glucocorticoids suppress inflammation, allergy and immune responses.

Question 11

What does excess cortisol production cause?

Answer 11

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.

Question 12

What is the treatment of Cushing’s disease?

Answer 12

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

Question 13

What does deficient cortisol production cause?

Answer 13

Addison’s disease.

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

Question 14

What is the treatment for Addison’s disease?

Answer 14

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

Question 15

When given in supraphysiologic doses, glucocorticoids have what effect?

Answer 15

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

Question 16

What are the clinical uses of glucocorticoids?

Answer 16

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

Question 17

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

Answer 17

Fluticasone.

Question 18

What is a glucocorticoid used to suppress autoimmune diseases?

Answer 18

Prednisolone.

Question 19

What glucocorticoid is used to reduce swelling in brain tumours?

Answer 19

Dexamethasone.

Question 20

What are some serious side effects of glucocorticoids?

Answer 20

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
-

Question 21

What are combined oral contraceptives?

Answer 21

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

Question 22

Oestrogens used for combined oral contraceptives?

Answer 22

Most commonly: ethinyloestradiol

Less commonly: mestranol

Question 23

Progestogen used in combined oral contraceptives?

Answer 23

Most commonly: levonorgestrel, norethisterone

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

Question 24

What is the mechanism of action of combined oral contraceptives?

Answer 24

Inhibit ovulation
Inhibit fertilisation
Inhibit successful implantation

Question 25

How effective is combined oral contraceptives?

Answer 25

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

Question 26

What are the benefits of combined oral contraceptives?

Answer 26

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

Question 27

Common adverse effects of combined oral contraceptives?

Answer 27

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

Question 28

Serious adverse effects of combined oral contraceptives?

Answer 28

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