Lecture 22 - Steroid Abnormalities

Question 1

Low glucose?

Answer 1

hypoglycaemia, glucocorticoid deficiency (cortisol)

Question 2

High potassium?

Answer 2

hyperkalaemia, mineralcorticoid deficiency (aldosterone)

Question 3

Mechanisms of glucocorticoid (cortisol) deficiency?

Answer 3

hyponatraemia (loss of cortisol driven ADH inhibition), hypoglycaemia (loss of gluconeogensis), hypotension (loss of cortisol effect on vascular tone)

Question 4

Mechanisms of mineralcorticoid (aldosterone) deficiency?

Answer 4

hyponatraemia (urine Na+ loss with intravascular volume contraction), hyperkalaemia (reduced K excretion), metabolic acidosis (reduced renal H+ excretion)

Question 5

Aldosterone homeostasis?

Answer 5

Angiotensin II + ACTH + K stimulate aldosterone production by adrenal cortex to increase sodium, water and therefore intravascular volumeq

Question 6

Types of adrenal failure?

Answer 6

primary (adrenal gland) and secondary (hypothalamus/pituitary)

Question 7

Identifying primary adrenal failure?

Answer 7

increased ACTH due to lack of cortisol for negative feedback

Question 8

Primary Adrenal Failure/A good tan?

Answer 8

lack of cortisol inhibition leads to increased POMC leading to increased ACTH and MSH (ATCH contains alpha-MSH also), increase of these products leads to pigmentation

Question 9

Simple obesity?

Answer 9

signs around 3-4yr, taller as kids but reverted to normal height in puberty due to glucocorticoid excess

Question 10

Other signs of glucocorticoid excess?

Answer 10

moon face, thinning skin, myopathy, androgen excess, hypertension, glucose intolerance

Question 11

Cortisol and receptor affinity?

Answer 11

equalt to glucocorticoid and mineralcorticoid, no mineralcorticoid effects due to rapid metabolism, effects occur in excess cortisol

Question 12

Partial loss of function of glucocorticoid receptor?

Answer 12

Glucocorticoid resistance - high cortisol, hypokalaemia, hypotension, hyperandrogenism, fatigue

Question 13

Loss of function of mineralcorticoid receptor?

Answer 13

Pseudohypoaldosteronism - high aldosterone and renin, high K and low Na, depleted ECF

Question 14

ACTH receptor loss of function mutation?

Answer 14

severe cortisol deficiency from birth - hypotension, low Na, hypoglycaemia

Question 15

XX karyotype leading to male phenotype?

Answer 15

defect in 21 hydroxylase -> lowered cortisol synthesis -> high ACTH -> high adrenal precursors and hyperplasia