Week 8: Adrenal hypofunction Flashcards
(70 cards)
Adrenal problems for the clinician
7 listed

Clinical Case Vignette

Identify


Identify


Steroid hormone synthesis

Hydrocortisone AKA
Cortisol

How do steroid hormones work?

Describe the regulatory relationships of the HPA axis

Describe the circadian and ultradian variation in HPA activity

When should you measure cortisol for Cushing’s syndrome?
Midnight
When should you measure cortisol for adrenal insufficiency?
Morning so adrenals are usually high at this time
CRH is made in?
hypothalamus
How is CRH measured?
really diluted in systemic circulation so would have to get from the hypothalamus pituitary protal system
So instead we measure ACTH
Describe the free-hormone hypothesis
many steroids have a binding protein however the free portion of the steroid is the biologically active fraction
Usually, the protein-bound form can be high and total steroid count can seem high but it could be in the inactive protein-bound form
*Measure total not free*

one big issue with exoogenous corticosteroids
Negative feedback inhibition on ACTH of the Ant. Pit. causing adrenal insufficiency
Describe the regulation of aldosterone secretion
Angiotensin II is the main positive regulator for aldosterone secretion

Aldosterone secretion positive regulators
6 listed
- Angiotensin II (main stimulatory regulator)
- Hyperkalemia
- Adrenocorticotropin
- Hyponatremia
- Angiotensin III
- Aldosterone-stimulating factor

Negative regulators of Aldosterone secretion
2 listed
- Atrial natriuretic factor
- Dopamine

Things that promote renal secretion of renin
5 listed
↓ effective blood volume
↓ blood pressure
↓ [NaCl] and [K+] at the diistal tubule
↑ prostaglandins
β-adrenergic stimulation

Primary Adrenal insufficiency hormones deficient
No aldosterone and no cortisone
Combined cortisol and aldosterone deficiency
Secondary vs primary adrenal insufficiency
Primary
- aldosterone and cortisol deficiency
- High levels of ACTH (due to loss of cortisol feedback on the pituitary)
Secondary
- Aldosterone is preserved
- cortisol deficiency is deficient
- low levels of ACTH
Adrenal medulla

SNS and the adrenal medulla

Describe the pathophysiology of adrenal disorders




















