Endocrine disorders

Question 1

relationship between calcium level and PTH

Answer 1

if plasma calcium falls then PTH secretion increases

Question 2

which thyroid hormone is more potent and which produced in larger quantity by the thyroid gland

Answer 2

T4 is produced more

T3 is more potent

Question 3

what is congenital hypothyroidism

Answer 3

failure to produce the hormone from birth

Question 4

symptoms of hypothyroidism

Answer 4

• reduced metabolism
• lethargy
• weight gain
• increased sensitivity to cold

Question 5

symptoms of hyperthyroidism

Answer 5

tachycardia
weight loss
fatigue
similar effects of increased sympathetic activity

Question 6

primary hyo/hyperthyroidism refers to what

Answer 6

it refers to problems with the thyroid glands itself

Question 7

secondary hypo/hyperthyroidism refers to what

Answer 7

it refers to problem with the pituitary or sometimes the hypothalamus

Question 8

what should you measure to look for hyper/hypothyroidisms

Answer 8

TSH

Question 9

what are the levels of T3/T4 in primary/secondary hypo/hyperthyroidism

Answer 9

T3/T4 in primary hypothyroidism= LOW
T3/T4 in secondary hypothyroidism= LOW
T3/T4 in primary hyperthyroidism= HIGH
T3/T4 in secondary hyperthyroidism=HIGH

Question 10

what are the levels of TSH in primary/secondary hypo/hyperthyroidism

Answer 10

TSH in primary hypothyroidism = HIGH
TSH in secondary hypothyroidism = LOW/NORMAL
TSH in primary hyperthyroidism = LOW
TSH in secondary hyperthyroidism = HIGH

Question 11

Anatomy of the adrenal gland

Answer 11

you have the inner medulla and outer cortex
in order from outer to innermost layer you have in the cortex:
Zona glomerulosa- mineralocorticoids (aldosterone)
Zona fasiculata- Gluco-cortcoids(cortisol)
Zona reticularis - adrenal androgens

Question 12

what are the disorders linked to adrenal hyperfunction

Answer 12

• excess cortisol (cushings syndrome)

- excess aldosterone( e.g conns syndrome)

Question 13

what are the disorders linked to adrenal insufficiency

Answer 13

• Hypocortisolism

- Lack of aldosterone and cortisol (Addison’s)

Question 14

is conns syndrome primary or secondary hyperaldosteronism

Answer 14

primary

Question 15

what 2 things activates aldosterone secretion

Answer 15

• RAAS

- increased plasma [Na+]

Question 16

How does RAAS work

Answer 16

specialised epithelial cells in the distal tubule called macula dense senses decreased sodium conc and communicates with juxtaglomerular cells which release rennin to the blood stream.
renin converts angiotensinogen to angiotensin I
and ACE converts angiotensin I to angiotensin II

Question 17

what are some of the effects of angiotensin II

Answer 17

increased aldosterone secretion
vasoconstriction
increased thirst

Question 18

what activates RAAS

Answer 18

reduced renal perfusion

Increased sympathetic activity

Question 19

what will happen if there is too much aldosterone

Answer 19

too much aldosterone= increased sodium reabsorption = increased expansion of extracellular volume= increased blood volume = increased BP (hypertension)

Question 20

what is useful in diagnosing primary hyperaldosteronism

Answer 20

Plasma aldosterone/ renin ration

Question 21

Difference between Cushing’s disease and Cushing’s syndrome

Answer 21

Cushing’s disease is due to ACTH-secreting pituitary
adenoma. Cushing’s syndrome may also be due to
ectopic ACTH source

Question 22

what test is done in differential diagnosis of Cushing’s syndromes

Answer 22

Dexamethasone test

Question 23

what are the clinical features of Addison’s

Answer 23

anorexia
fatigue
hyperpigmentation
hypotension
normal to low plasma sodium conc
normal to high plasma sodium conc
high ACTH
Elevated plasma renin

Question 24

what is the hallmarks of Addison’s disease

Answer 24

high ATCH and low cortisol

Question 25

ACTH stimulation test

Answer 25

Assess ability of adrenal to produce cortisol in response to ACTH
Short synacthen test
• Measure baseline cortisol (9am) and 30 min after 250 ug synacthen (synthetic ACTH) i.m.
• Adrenal insufficiency is excluded by an increase in cortisol of >200 nmol/L and/or a 30
min value >550
Long synacthen test
• Adrenal cortex ‘shuts down’ in absence of stimulation by ACTH — time needed to regain
responsiveness
• 3-day stimulation with synacthen
• In secondary (but not primary) adrenal insufficiency cortisol increases by >200 nmol/L
over baseline
• Long test not often necessary since ACTH assay can distinguish