endocrine disorders

Question 1

describe disorders of adrenocortical function

Answer 1

excess corticol = cushing’s syndrome
excess aldosterone = conn’s syndrome
hypercortisolism
lack of aldosterone and cortisol

Question 2

describe aldosterone excess

Answer 2

conns = primary hyperaldosteronsim 
cushings = may be primary or secondary

Question 3

control of aldosterone secretion

Answer 3

activated by RAAS and increased plasma 
RAAS is acitvated by: 
renal perfusion decrease
increased sympathetic activity 
both interpreted as full in blood volume 

plasma aldosterone/renin ratio is useful in diagnosis of primary hyperaldosteronism
more sodium reabsorbiton occurs and water
increased extracellular fluid volume and increased blood volume = increased blood pressure
high aldosterone and low renin = primary hyeraldosteronism

Question 4

describe major action of cortisol on metabolism and other targets of cortisol action

Answer 4

promotes insulin resistance in skeletal muscle

promotes glycolysis/gluconeogenesis

Question 5

most common cause of cushing’s syndrome

Answer 5

= latrogenic

exogenous glucocorticoids activate cortisol receptors
at high doses will shut down HPA
adrenal cortex atrophies with lack of ACTH stimulation
several days may be required for adrenal to become responsive to ACTH again
cushing’s disease = due to ACTH secreting pituitary adenoma

Question 6

levels of plasma ACTH in cushing’s syndrome

Answer 6

cushing = high

adrenal tumour = low

ectopic ACTH = v high

Question 7

describe adrenal insufficiency

Answer 7

primary = addison’s disease
-insufficient control and aldosterone

secondary = pituitary or hypothalamic disease
insufficient cortisol

Question 8

clinical factors of addison’s

Answer 8

hypotension
anorexia/weakness
high ACTH
elevated plasma renin

Question 9

describe ACTH stimulation test

Answer 9

assess ability of adrenal to produce cortisol in response to ACTH

Question 10

short synacthen test

Answer 10

measure baseline cortisol, 30 mins after 250 microgram

adrenal insufficiency = increase of cortisol > 200mol

Question 11

long synacthen test

Answer 11

adrenal cortex shuts down in absence of stimulation by ACTH
3 day stimulation with synacthen
in secondary adrenal insufficiency cortisol increase by > 200nmol over baseline
long test not necessary as ACTH assay can distinguish