adrenal tutorial

Question 1

what is hypercortisolism called?

Answer 1

cushings syndrome

Question 2

what are the symptoms associated with cushings syndrome & explain why they occur?

Answer 2

• hyperglycemia- cortisol increases plasma glucose levels (via gluconeogenesis etc)
  * weight gain - accumulation of lipids
• increased susectibility to infection (due to decrease in immune response caused by high cortisol)
• thin hair - causes hair follicles to shrink
• acne
• **hirsutism **- hair growth on face/chest or abdomen ( NB women) -
• menstrual cycle disturbances

Question 3

Why is thin hair associated with cushings syndrome?

Answer 3

as high levels of cortisol can cause shrinkage of the hair follicles , causing hair loss and thin hair

Question 4

why is hirsutism associated with cushings syndrome?

Answer 4

• due to the high levels of androgens in the body (due to high ACTH which stimulates androgen secretion)
• androgens in excess amounts cause hirsutism

Question 5

why does high levels of cortisol cause menstrual disturbances?

Answer 5

• high levels of cortisol in the body can interfere with the normal functioning of the pit gland and hypothalamus
• this can lead to irregular periods or a complete absence of periods
• the high levels of cortisol can also interfere with the production of esterogen and progesterone

Question 6

Describe addisons disease and its symptoms

Answer 6

• addisons disease is an autoimmune disorder which destructs the adrenal gland
• this causes both cortisol and aldosterone insufficiency
• symptoms associated with AD include hypoglycemia, postural hypotension, pigmentation of skin, hyponatemia, hyperkalemia, muscke weakness

Question 7

what causes the hyperpigmentation in addisons disease?

Answer 7

the elevation in the melanocyte stimulating hormone (MSH)

Question 8

what is hyperaldosteronism called?

Answer 8

Conn’s syndrome

Question 9

what are the symptoms associated with Conns syndrome and explain why?

think about the ions it affects

Answer 9

* hypernatremia - due to the increased reabsorption of Na+
* hypokalemia - due to the increased excretion of K+
* increased H+ excretion and HCO3- reabsorption which can cause metabolic acidosis
* increased H20 reabsorption (as a result of osmosis following Na+) leading to hypertension

Question 10

what are the actions of aldosterone on the intercalated cells in the renal tubule RECAP?

Answer 10

aldosterone increases H+ excretion and increases HCO3- reabsorption

Question 11

in addisons disease, why is there a change in the distribution of body hair?

Answer 11

• as there is a reduction of cortisol, there is a reduced negative feedback effect on ACTH
• this means that there is an increased secretion of ACTH which stimulates androgen production which will cause changes in body hair (virsilisation)

Question 12

what is virsilisation?

Answer 12

• a condition in which a female develops characteristics associated with male hormones (androgens)

Question 13

what enzyme is deficient in congential adrenal hyperplasia ?

Answer 13

21beta-hydroxylase

Question 14

what is the effect of congenital adrenal hyperplasia on cortisol, aldosterone, ACTH and androgen secretion?

Answer 14

• decrease in cortisol secretion due to the enzyme deficiency that makes cortisol
• decrease in aldosterone secretion due to the enzyme deficiency that makes the hormone
• increase in male androgen secretion
• increase in ACTH - due to a reduced negative feedback on ACTH by cortisol

Question 15

A patient with lethargy, nausea, and reported muscle weakness is given a series of tests to rule out physical causes. During these tests it is revealed that **plasma corticotropin (ACTH) is above normal **and cortisol is below normal. Renin is above normal and aldosterone is below normal. Adrenal androgens are above normal. Which clinical conditions would be most likely to produce this set of signs and symptoms?

Answer 15

addisons disease

cortisol and aldosterone are low
ACTH is high due to reduced negative feedback from cortisol
androgens are high due to high ACTH

Question 16

A 34y old woman was referred to the Endocrine clinic at her local hospital by her GP. Her case history indicated** considerable weight gain** (12kg in previous 6 months), facial hirsutism, **thinning of hair **on head, spontaneous bruising and muscle weakness. She had a fasting plasma glucose of 11mmol/l and washypertensive. She was on no medication, had no significant past history or family history… WHAT ARE THE KEY OBSERVATIONS.. WHAT ENDOCRINE DISORDER COULD THIS BE?

Answer 16

• weight gain
• muscle weakness
• hyperglycemia
• hirsutism

cushings? - due to high cortisol levels, hirsutism, low K+ levels could cause muscle weakness

Question 17

the patients results showed high ACTH and cortisol, why is a adrenal adenoma ruled out?

Answer 17

if there was a adrenal adenoma, the ACTH levels would be supressed by increased feedback inhibition by cortisol

Question 18

what is the dexamethasone supression test used for?

Answer 18

• used to assess adrenal gland function by measuring how cortisol levels change in response to oral doses of dexamethasone
• used to diagnose cushings syndrome

Question 19

what is dexamethasone?

Answer 19

• a steroid that provides negative feedback to the pit to supress the secretion of ACTH

Question 20

what is a normal result to a dexamethasone supression test?

Answer 20

• a decrease in cortisol

Question 21

How would cushing’s syndrome affect the dexamethasone supression test? also explain how cushings disease would affect it

Answer 21

• there would be a failure to supress ACTH - therefore the cortisol levels would be high and unchanged - may due to a non pituitary tumour
• if it was cushings disease which is caused by a pituitary tumour secreting ACTH, it would respond to the dexamethasone and cortisol levels would drop

Question 22

what is the difference between cushings syndrome and cushings disease?

Answer 22

• cushings disease is a type of cushings syndrome
• cushings disease is associated with a pituitary tumour causing excess ACTH secretion and therefore high cortisol levels
• cushings syndrome is not associated with a pit tumour, however other tumors eg ectopic tumours may be the cause
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