Endocrinology and Growth

Question 1

Major drivers of growth in infancy?

Answer 1

nutrition and insulin

Question 2

Major drivers of growth in childhood?

Answer 2

growth hormone and thyroxine

Question 3

Major drivers of growth in puberty?

Answer 3

Sex steroids and growth hormone

Question 4

Effects of PTH on bone?

Answer 4

Binds to osteoblasts which signal to osteoclasts to cause resorption of bone and release calcium.

Question 5

Effects of PTH on kidneys?

Answer 5

Active reabsorption of Ca and Mg from the distal convoluted tubule. Decreases reabsorption of PO4.

Question 6

Effects of PTH on intestine (via kidneys)?

Answer 6

Increases intestinal calcium absorption by increasing activated vitamin D. Activated vitamin D increases calcium absorption.

Question 7

Definition of PCOS?

Answer 7

at least two of the following:
(Rotterdam criteria):
- Polycystic ovaries (more than 12 cysts)
- Oligo-ovulation or anovulation
- Hyperandrogenism (clinical or biochemical)

Question 8

Symptoms of PCOS?

Answer 8

• Oligomenorrhoea (defined as <9 periods per year)
• Infertility, subfertility
• Acne, oily skin, increased skin pigmentation
• Hirsutism, male pattern baldness or alopecia
• Obesity or difficulty losing weight

Question 9

How can metformin help in PCOS?

Answer 9

Reduce insulin resistance
Fall in serum androgens
Induce ovulation
Fall in LH
Reduction in weight

Question 10

What does LH and FSH do in males?

Answer 10

LH stimulates the testes -> testosterone.

FSH (and testosterone) causes the testes to produce sperm.

Question 11

First sign of puberty?

Answer 11

enlargement of the testes (once they reach 4 ml, puberty has commenced)

Question 12

Testicular size denoting commencement of puberty?

Answer 12

4mL

Question 13

Stages of puberty?

Answer 13

enlargement of the testes -> lengthening of the penis -> pubic hair -> ejaculation/ facial hair

Question 14

Brown-Sequard Syndrome features?

Answer 14

• ipsilateral spastic paralysis (corticospinal tract)
• ipsilateral loss of proprioception and vibration (dorsal column)
• contralateral loss of pain and temperature sensation (spinothalamic tract)

Question 15

Effect of cortisol on BP?

Answer 15

Increases BP: permits normal response to angiotensin II and catecholamines by up-regulating a1 receptors on arterioles

Question 16

Effect of cortisol on bone?

Answer 16

Inhibits bone formation: decreases osteoblasts, decreases type 1 collagen, decreases absorption of calcium from the gut, increases osteoclastic activity

Question 17

Most common cause of primary adrenal insufficiency?

Answer 17

80 % due to autoimmune destruction (Addison’s disease)

Other causes: congenital adrenal hyperplasia, adenoma, or idiopathic

Question 18

Most common cause of secondary adrenal insufficiency?

Answer 18

exogenous steroid use -> impairment of pituitary/ hypothalamus

other causes: pituitary adenoma, hypothalamic tumors, surgical damage, and Sheehan’s syndrome (maternal ischemic necrosis related to childbirth)

Question 19

autosomal recessive condition: obesity, retinitis pigmentosa, polydactyly, hypogonadism, and kidney failure

Answer 19

Bardet-Biedl syndrome

children lose their vision by adolescence or early childhood

Question 20

complications of thyroidectomy?

Answer 20

• postop haemorrhage and haematoma formation, this can rapidly compress the airway
• recurrent laryngeal n palsy -> hoarse voice
• hypoparathyroidism + low Ca due to removal/ damage of parathyroids

Question 21

most common cause of thyroid problems?

Answer 21

autoimmunity.

Graves/ Hashimotos

Question 22

What drug can cause thyrotoxicosis?

Answer 22

amiodarone

Question 23

What is Riedel thyroiditis?

Answer 23

fibrous tissue replacing the normal thyroid parenchyma

causes a painless goitre + hypothyroidism

Question 24

What drugs may cause hypothyroidism?

Answer 24

Lithium, Amiodarone

Question 25

Most common cause of hypothyroidism in the developing world?

Answer 25

Iodine deficiency

Question 26

Effects of thyroid dysfunction on periods?

Answer 26

hypothyroid - menorrhagia | hyperthyroid - oligomenorrhoea

Question 27

Neurological symptoms of hypothyroidism?

Answer 27

Decreased deep tendon reflexes Carpal tunnel syndrome

Question 28

Most common antibodies in Hashimoto's?

Answer 28

anti-Thyroid Peroxidase

Question 29

Most common antibodies in Grave's disease?

Answer 29

TSH receptor antibodies | Thyroglobulin antibodies

Question 30

Mx of thyrotoxicosis?

Answer 30

dependent on underlying cause. Propranolol: to control thyrotoxic symptoms such as tremor Carbimazole: blocks thyroid peroxidase from coupling and iodinating the tyrosine residues on thyroglobulin → reducing thyroid hormone production. (SE: Agranulocytosis) Radioiodine treatment

Question 31

What is an arrhenoblastoma?

Answer 31

rare types of ovarian tumours which most often secrete testosterone -> virilisation of girls as well as some oestrogen -> precocious puberty.

Question 32

Tx of GnRH-dependent precocious puberty?

Answer 32

GnRH agonist

Question 33

most common enzyme deficiency in congenital adrenal hyperplasia?

Answer 33

21-hydroxylase deficiency (90% of cases) -> cortisol deficiency and sometimes an associated aldosterone deficiency and androgen excess

Question 34

2nd most common enzyme deficiency in congenital adrenal hyperplasia?

Answer 34

11-beta-hydroxylase

Question 35

features of salt-losing congenital adrenal hyperplasia?

Answer 35

Due to aldosterone deficiency, seen in the first few weeks of life as an adrenal crisis Females have ambiguous external genitalia

Question 36

features of non salt-losing congenital adrenal hyperplasia?

Answer 36

Presents during childhood with low glucocorticoids and high androgens Males present with virilisation age 2-4 years females - ambiguous external genitalia

Question 37

Characteristics of McCune-Albright Syndrome?

Answer 37

At least 2 of 3: 1. polyostotic fibrous dysplasia (fibrous tissue in bones) 2. café-au-lait spots 3. autonomous endocrine hyperfunction (eg, gonadotropin-independent precocious puberty) +/- hyperthyroidism, acromegaly, and Cushing syndrome.

Question 38

Venous drainage of the adrenals?

Answer 38

R adrenal drains directly into IVC L adrenal drains into L renal vein

Question 39

Physical features of Turner's syndrome?

Answer 39

- Lymphoedema and rocker bottom feet at birth - Short stature - Webbed neck - Broad chest - Less common: multiple naevi, poorly developed nails, ptosis, low hairline

Question 40

Cardiac associations of Turner's Syndrome?

Answer 40

- most frequently coarctation of the aorta aortic dissection bicuspid aortic valve hypertension.

Question 41

Endocrine features of Turner's Syndrome?

Answer 41

relating to gonadal dysgenesis: Amenorrhoea Dlayed or absent puberty Infertility

Question 42

Mx of Turner's Syndrome?

Answer 42

Growth Hormone to initiate puberty. Once satisfactory growth and development has been achieved, GH stopped and oestrogen started. Progesterone is added at the time of puberty to induce withdrawal bleeds.

Question 43

Features of 17-hydroxylase deficiency?

Answer 43

congenital adrenal hyperplasia: - non-virilising in females - inter-sex in boys - hypertension

Question 44

Features of 11-beta hydroxylase deficiency?

Answer 44

congenital adrenal hyperplasia: - virilisation of female genitalia - precocious puberty in males - hypertension - hypokalaemia

Question 45

Where is testosterone produced?

Answer 45

Leydig cells. small amounts produced in the adrenal glands.