Adrenal Insufficiency Flashcards
What is the definition of adrenal insufficiency?
Clinical manifestation of deficient cortisol
What is the major difference between primary and secondary adrenal insufficiency it terms of the loss of hormones?
Primary loses all three hormones, while secondary does not lose aldosterone
What are the two major etiologies of secondary adrenal insufficiency?
Deficiency in CRH or ACTH
What portion of the adrenal gland is the medulla? What does this secrete?
20%
Catecholamines
What are the three layers of the adrenal glands, and what does each secrete?
GFR, salt, sugar, sex
What causes the release of catecholamines from the adrenal medulla? When does this occur?
Sympathetic nerve input
-Fight or flight response
What are the three catecholamines released by the adrenal medulla?
Epi
NE
Dopamine
Why is it that there is no clinical syndroem associated with adrenal medulla insufficiency?
There are extra-adrenal sites of catecholamine production (paragangliomas along the spinal cord)
What is the tumor that causes an over secretion of catecholamines?
Pheochromocytoma
What are the two adrenal androgens? What are these precursors of?
DHEA
Androstenedione
Dihydrotesterone and testosterone
True or false: adrenal androgen production is stimulated by ACTH
True, but weak
What is the importance of DHEA?
Contributes to the development of secondary sexual characteristics in puberty
Why is there no issue with a lack of DHEA secretion from the adrenal medulla?
Androgens are made in the tests and the ovaries
What are the three major etiologies of adrenal androgen overproduction?
Congenital adrenal hyperplasia
Adrenal tumors
Cushing’s
What is the main mineralocorticoid? What is the action of this?
Aldosterone
Causes principal cells of the kidneys to secrete K in exchange for Na and water
Where in the nephron does aldosterone have effect?
Distal convoluted tubule
Renal collecting duct
What regulates aldosterone production?
Renin-angiotensin system
Where is renin released from? What does this do?
Juxtaglomerular cells
Cleaves circulating angiotensinogen into ANG I
What is the enzyme that converts ANG I to ANG II? Where is this found?
ACE
Lungs and kidneys
What are the two stimuli for renin release?
- Decreased BP/renal artery hypotension
- Decreased Na delivery to the distal tubules
What is the effect of ANG II on the kidneys?
Increases aldosterone release
What is the effect of ANG II on the vasculature?
Vasoconstriction
What is the effect of ANG II on the HPA axis?
Increases the release of ADH from the posterior pituitary and stimulates thirst
What area of the brain is responsible for thirst and cooling?
Anterior hypothalamus
What is the effect of ANG II on NE release?
Increases
What is the effect of ANG II on the heart?
Stimulates hypertrophy
How does cortisol inhibit the immune response?
Inhibits the production of Leukotrienes
What is the effect of glucocorticoids on metabolism?
Increases BG
Increases lipolysis
Increases proteolysis
What is the effect of cortisol on fibroblasts?
Decreases/inhibits them
What are the cells in the anterior pituitary that synthesize and release ACTH? What stimulates them to do this?
Corticotroph cells
CRH
What are the two acidophils of the anterior pituitary?
Lactotrophs
Somatotrophs
(A PiG)
What are the four basophils of the anterior pituitary?
FSH
LH (gonadotrophs)
ACTH (corticotrophs)
TSH (thyrotrophs)
(B-FLAT)
What are the two breakdown products of POMC?
MSH
ACTH
What happens to renin, aldosterone, and ACTH levels with primary adrenal insufficiency?
High renin and ACTH
Low Aldosterone
What is the treatment for primary adrenal insufficiency?
Fludrocortisone + hydrocortisone
What is synthetic aldosterone?
Fludrocortisone
What are the major etiologies of primary adrenal insufficiency? (2 one most common in developed countries, and undeveloped)
Autoimmune destruction
TB granuloma
What are the antibodies that are found with primary adrenal insufficiency?
21-hydroxylase antibodies
What are the gross findings associated with autoimmune destruction of the adrenal glands vs TB infiltration?
Autoimmune = small, fibrotic
TB = Caseating granuloma
What is the common fungal causes of primary adrenal insufficiency?
Histoplasmosis
What is the major cause of hemorrhage into the adrenal glands? What is the name of this syndrome?
Warfarin
Waterhouse-friderichsen syndrome
For metastatic causes of adrenal insufficiency, what percent of the gland must be affected before seeing ssx?
90%
What are the three major medications that can cause primary adrenal insufficiency?
Ketoconazole
Aminoglutethimide
Rifampin
What are the following lab findings like with primary adrenal insufficiency:
- cortisol
- aldosterone
- DHEA
- ACTH
- Renin
- cortisol = low
- aldosterone = low
- DHEA = low
- ACTH = high
- Renin = high
What are the two symptoms that are specific to primary adrenal insufficiency, as opposed to other forms of adrenal insufficiency?
Hyperpigmentation from POMC production
Hyperkalemia from lack of aldosterone
What is the value of cortisol that is diagnostic of primary adrenal insufficiency (morning random)?
Morning cortisol less than 3 mcg
Random less than 5 mcg
What is the name of synthetic ACTH?
Cortrosyn stimulation test
What is the reasoning behind the cortrosyn stimulation test? What are the results of this?
Injecting ACTH, wait 30 mins, and measure cortisol levels.
–Should have a more than 18 mcg/dL increase. If not, Addison’s disease
What are the common acute symptoms of Addison’s disease?
Postural hypotension
Arthralgias/myalgias
Abdo pain
What are the common chronic ssx of AI?
Weakness
Anorexia
Nausea
How do you monitor exogenous cortisol administration?
Weight/BP
Lytes
Well being
True or false: the smallest dose of exogenous cortisol should be used in pts with primary AI
True
What should patients with Addison’s disease do when sick? After major surgery?
Double when sick
200-300 mg/day post op
What are the 5 “S’s” of treating an adrenal crisis?
- Salt (NS)
- Sugar (5% dextrose)
- Steroids
- Support
- Search for precipitating cause
How do you taper off steroids for a AI pt following surgery?
Taper for a few days as tolerated until physiological levels achieved
What is the minimal amount of steroids that can cause transient adrenal insufficiency?
15 mg for x14 days
How do you differentiate secondary AI from primary AI in the clinic?
Measure ACTH levels–will be decreased with secondary causes
Why is it that secondary AI can show a lack of response with a cortrosyn stimulation test?
Adrenal gland atrophy
What is the basis of rh metyrapone test, and what are the results that can be expected?
Metyrapone blocks 11-deoxycortisol/compensatory, causing an increase in ACTH under normal conditions. If there is not, then secondary AI
What is the insulin induced hypoglycemia test done for?
Hypoglycemia should cause ACTH secretion, thus by measure ACTH following insulin.
What is the treatment for secondary AI?
- Hydrocortisone 16 mg daily
- Prednisone once daily
What is the lab test that can be done to confirm that the HPA axis has recovered after long term administration of corticosteroids?
Measure morning cortisol levels–needs to be more than 10 mcg/dL
Which should always be corrected first: cortisol levels, or thyroid levels? Why?
Cortisol, since thyroid may increase renal clearance, and cause an adrenal crisis