Endo - Adrenals

Question 1

Hormone produced by Adrenal Medulla?

Answer 1

Adrenaline

Question 2

Hormone produced by zona glomerulosa and mediated by?

Answer 2

Aldosterone

Mediated by K+ level and angiotensin II

Question 3

Hormone produced by zona fasciculata and mediated by?

Answer 3

Cortisol

ACTH

Question 4

Hormone produced by zona reticularis and mediated by?

Answer 4

DHEAS (androgens)

ACTH

Question 5

Cortisol peak and trough?

Answer 5

Highest on waking
Lowest asleep (midnight)

Question 6

Functions of cortisol?

Answer 6

Hyperglycaemia
Increased gluconeogenesis and resistance to insulin
Decreased lymph/mono/eos and B & T cells
Decreased growth
Decreased Ca+
Increased bone resorption
Increased androgens

Question 7

Aldosterone stimulated by?

Answer 7

Angiotensin II
Hyperkalameia
ACTH

Question 8

Aldosterone inhibited by?

Answer 8

Atrial Naturietic Peptide

Question 9

Function of aldosterone?

Answer 9

Maintain intravascular volume
Increases Na channel expression in renal collecting ducts which increases Na+ resorption (bringing H20) and increases K+ excretion

Question 10

Function of adrenaline and noradrenaline?

Answer 10

Raise MAP

Adrenaline increases cardiac output

Question 11

1mg pred =?hydrocort
1mg Methylpred = ?hydrocort
1mg dexamethasone = ?hydrocort

Answer 11

1mg pred =4mg hydrocort
1mg Methylpred = 5mg hydrocort
1mg dexamethasone = 25mg hydrocort

Question 12

Physiological requirement of hydrocortisone?

Answer 12

10mg/m2/day

Question 13

Primary adrenal insufficiency due to what?

Answer 13

Inadequate adrenal function

Deficit in glucocorticoids and mineralocorticoids

Question 14

Central adrenal insufficiency due to what?

Answer 14

Secondary - pituitary defect (ACTH)
Tertiary - hypothalamic defect (corticotrophin releasing hormone)
Deficit in glucocorticoids only

Question 15

Signs of primary adrenal insufficiency?

Answer 15

Low cortisol
High ACTH
Hyponatremia
Hyperkalaemia
HTN
Hyperpigmentation of skin (bronze)
Fasting hypoglycaemia

Question 16

Signs of secondary adrenal insufficiency?

Answer 16

Low cortisol
Low ACTH
Fasting hypoglycaemia
Increased insulin sensitivity
FTT, GIT upset, fatigue, weakness

Question 17

Most common cause of primary adrenal insufficiency?

Answer 17

Congenital Adrenal Hyperplasia

Question 18

Signs of over replacement of glucocorticoids?

Answer 18

Excess hydrocortisone dose = weight gain, cushingoid features

Question 19

Sign of under replacement of glucocorticoids?

Answer 19

Insufficient hydrocortisone dose = hyperpigmentation, hypoglycaemia, FTT, high ACTH

Question 20

Signs of over replacement of mineralocorticoids?

Answer 20

Excess fludrocortisone = HTN and low renin

Question 21

Signs of under replacement of mineralocorticoids?

Answer 21

Insufficient fludrocortisone = salt craving, hyponatremia, hyperkalaemia, hypotension, high renin

Question 22

Most common form of CAH?

Answer 22

21 hydroxylase deficiency

Question 23

Second most common cause of CAH?

Answer 23

11-beta-hydroxylase deficiency

Question 24

Signs of 21 hydroxylase deficiency (classic) CAH?

Answer 24

Glucocorticoid deficiency
Mineralocorticoid deficiency
(typically adrenal crisis by D10-14 of life)
Ambiguous genitalia in females
Early virilisation - pubic/axillary hair, early skeletal maturation

Question 25

How is height affected in classic CAH?

Answer 25

Final height 8-10cm shorter

Question 26

Signs non-classic CAH?

Answer 26

Normal glucocorticoid and mineralocorticoid function Isolated hyperandrogenism without adrenal insufficiency Premature pubarche, BO, hisutism, pubic hair Advanced bone age, reduced adult height

Question 27

Why does 11 beta hydroxylase deficiency have some mineralocorticoid function?

Answer 27

Blocks conversion of DOC to corticosterone and 11-DOC to cortisol however there is an adjacent pathway that is unaffected allowing aldosterone synthase production DOC has mineralocorticoid function

Question 28

Clinical manifestation of 11 beta hydroxylase deficiency?

Answer 28

Excess androgens (but milder than CAH) Excess mineralocorticoids (via DOC) Cortisol insufficiency -> HTN, hyperkalaemia, ambiguous female genitalia/increased penis size

Question 29

Treatment of 11 beta hydroxylase deficiency?

Answer 29

Hydrocortisone | Don't give fludrocortisone usually - sometimes even need Spiro as mineralocorticoid antagonist

Question 30

Cushing syndrome vs Cushing disease?

Answer 30

``` Syndrome = prolonged glucocorticoid excess Disease = specifically ACTH secreting pit adenoma ```

Question 31

Cushing syndrome + precocious puberty, fibrous dysplasia and cafe au lait?

Answer 31

McCune Albright

Question 32

Causes of ectopic ACTH production?

Answer 32

``` Islet cell ca neuroblastoma Ganglioneuroblastoma Wilms Thymic carcinoid ```

Question 33

How does 2 step Dex suppression test differentiate ACTH dependant and independent cushing syndrome?

Answer 33

ACTH-independant (secondary) causes not suppressed with smaller or larger dose of cortisol ACTH-dependant (central) causes will be suppressed with larger dose

Question 34

What is Conn's Syndrome?

Answer 34

Excess aldosterone secretion (independent of RAAS)

Question 35

Child with hypernatremia, hypokalaemia, hypertension and high aldosterone and decreased renin activity?

Answer 35

Conn's Syndrome

Question 36

Causes of Conn's?

Answer 36

Aldosterone secreting adenoma Bilateral nodular adrenocortical hyperplasia Unilateral hyperplasia

Question 37

Cancer syndromes assoc w adrenocortical tumours?

Answer 37

``` Li Fraumeni (p53) MEN1 Familial adenomatous polyposis PRKAR1A Beckwith-Wiedemann ```

Question 38

Child presents with HTN, tachycardia, sweating, headache. Progresses to hypertensive encephalopathy. Good appetite but failing to thrive. Dx?

Answer 38

Phaechromocytoma

Question 39

What is a phaechromocytoma?

Answer 39

Catecholamine secreting tumour arising from chromatin cells -> produced adrenaline, noradrenaline and dopamine In adrenal medulla 90% 10% elsewhere in sympathetic chain

Question 40

80% of phaeos related to familial disorders - what are these?

Answer 40

``` Von Hippel-Lindau MEN2A and 2B (bilat adrenalectomy req due to risk) NF1 TS Sturge Weber Ataxia-Telangiectasia ```

Question 41

How to differentiate catecholamine secreting phaeo vs neuroblastoma?

Answer 41

Urine catechols higher in phaeo | Dopamine and homovanillic acid higher in neuroblastoma

Question 42

Retinal and CNA haemangioblastomas, phaechromocytoma what tumour suppressor defect?

Answer 42

Von Hippel-Lindau (VHL tumour suppressor mutation)