Question

Question Set A: Thad has symptoms of Addison's disease (low cortisol). Blood tests confirm that Thad's cortisol secretion is sub-normal. 1. What 3 organs could potentially be malfunctioning? 2. How can we figure out which of the above organs is malfunctioning? Make a chart showing the predictions of blood hormone levels for each possibility. 3. His CRH and ACTH are elevated. Where is the source of the problem? 4. What other hormone/s might also be depressed, knowing there is an insufficiency at this gland? Predicts some other symptoms he might have, based on the other possible deficiency/ies. 5. For each of the above hormones, does it bind an internal or external receptor?

Answer 1

ADDISON DISEASE is Chronic adrenal insufficiency .

1) Organs malfunctioning - Adrenals ,Pituitary and Hypothalamus .

a)Adrenals ( primary adrenal insufficiency ) - because of defect in adrenal glands all the hormones will be decreased . Cortisol ,aldosterone and dihydroepiandrostenidione( sex hormones)

b) Pituitary :Secondary adrenal insufficiency Decrease ACTH adrenocorticotrophic hormone leads to decrease in cortisol ,Dihydroandrostenidione but normal aldosterone levels .( because aldosterone is secreted from zona goomerula which is under influence of Renin angiotensin aldosterone system RAAS) ..

c)Hypothalamus

2.Approach for diagnosis .

We do screening test at around 8 am in morning plasma Cortisol is more than 20 MCG/dl normal value .

If value is less than 3 MCG/dl ------Adrenal insufficiency is present

For values between 3-20 MCG/dl we do the confirmatory test .

We do the ACTH stimulation test/CO syntropin test/Synacthem stimulation test .In this test we give 250 MCG of ACTH iv or im and Cortisol levels are checked after 1 hr if Cortisol levels more than 20 MCG/dl then results are normal if less than 20 mcg then Addison DISEASE is confirmed .

Explanation : If ater giving ACTH Cortisol level increases then the problem is in Pituitary or Hypothalamus as Pituitary is not able to secrete ACTH as hyoothamus is not sending signals through CRH corticotropin releasing hormone .

If after ACTH stimulation as well low Cortisol suggest primary Adrenals insufficiency because of involvement of Adrenals .

3)Problem is in adrenal glands as CRH and ACTH are increased .

4)Other hormones decreased are Aldosterone ,DHEAS and androstenidione

Effects of decrease in cortisol - Fatigue ,asthenia ,tiredness,loss of appetite ,loss of weight ,Hypoglycemia ,Hypotension

Aldosterone effects ---loss of salt and water orthostatic hypotension ,giddiness,salt craving hyperkalemia

Dihydroepiandrostenidione and androstenidione effects ---- loss of libido ,dry skin,decreased body hair .

5) Cortisol bind glucocoticoid mineral elements located in cytoplasm .

Aldosterone bind on V1 receptors in collecting duct

DHEAs act on NMDA receptors ( N methyl D aspartate )