Adrenals Flashcards
Starting from the outside, what are the layers of the adrenal gland?
capsule, zona glomerulosa, zona fasciculata, zona reticulata, medulla
What area of the adrenal gland is NOT under control of ACTH?
- Zona Glomerulosa: Mineralicorticoids (Ex: Aldosterone)
- under Angiotensin II control ([K+])
What are the Adrenal products secreted via ACTH stimulation?
Zona Fasciculata: Glucocorticoids (Cortisol)
Zona Reticulata: Adrogens (DHEA androstenedione)
What are the products of the Zona Reticulata?
Androgens (DHEA, androstenedione)
What is the only steroid hormone that is not protein-bound in the blood?
DHEA (it is sulfated)
Cyp450scc (CypIIa; aka Desmolase) is an enzyme that does what?
Converts Cholesterol into Pregnenolone
All of the Congenital Adrenal Hyperplasias exhibit what 2 signs?
Lo cortisol, thus Hi ACTH (which grows the adrenal)
Having a congenital 17a-hydroxylase (cyp17) deficiency will effectively ‘turn off’ what areas?
- turn off the zona fasciculata, reticularis
- turn of the Gonads too! (testes/ovaries)
Having a congenital 21-hydroxylase deficiency will effectively ‘turn-off’ what areas?
-turn off zona glomerulosa and zona fasciculata
Having a congenital 11B-hydroxylase deficiency will effectively ‘turn off’ what areas?
-turn off zona glomerulosa and zona fasciculata
Primary Adrenal Insufficiency involves what gland and messenger?
- Crappy cortex
- lo cortisol leads to hi POMC/ACTH
What are 4 causes of Primary Adrenal Insufficiency in order of occurrence?
#1: autoimmune adrenalitis #2: Infectious adrenalitis (TB, fungal, HIV related, lung mets) #3: Adrenal hemorrhage (post-meningococcal) #4: Adrenomyeloneuropathy (X linked, men)
What are some common signs and symptoms of PAI/Addison disease?
- weakness, fatigue, anorexia/wt loss
- hypoNa, hyperK, acidosis, hyperpigmentation
Cushing’s syndrome is an excess of what?
cortisol
Describe a typical patient with Cushing’s
- Fat (buffalo hump, moon face, truncal obesity)
- Weak (atrophied mm, lo immune, osteoporosis)
- Hypertensive
Why are Cushing’s pts fat?
- cortisol will increase BLOOD GLUCOSE
- this leads to hi insulin, which increases adipose uptake
Why are Cushing’s pts weak?
- cortisol encourages protein catabolism (muscles, bones, joints)
- inhibits Phospholipase A2, IL-2, and histamine
Why are Cushing’s pts hypertensive?
- cortisol has a permissive effect on catecholamines
- excess cortisol=excess alpha1 receptors
Describe the top 4 causes of Cushing’s syndrome.
- exogenous corticosteroids
- primary adrenal adenoma
- secondary ACTH pituitary adenoma
- paraneoplastic ACTH (Ex: small cell lung carcinoma)
What two tests are run if hi cortisol is expected?
- lo dose dexamethasone (should suppress cortisol; tells if have hi cortisol)
- hi dose dexamethasone (tells us where its from)
Hyperaldosteronism classically presents with what 2 signs?
-hypokalemia, metabolic alkalosis, HTN
Describe primary and secondary causes for hyperaldosteronism.
- Primary: most often adrenal adenoma (Conn’s)
- Secondary: overactivation of RAA system (ex: renal artery stenosis/fibromuscular dysplasia)
What is the clinical difference between 11B-hydroxylase and 21-hydroxylase deficiencies?
- 11B-OH: less aldosterone deficiency signs (allows for production of 11-DOC, which is a mild version of aldosterone)
- 21-OH: will show aldosterone and cortisol deficiency signs
Describe the connection between Meningococcal infection and adrenals.
Waterhouse-Friedrichsen syndrome
- Neisseria meningitidis infection
- presents with DIC
- then bilateral adrenal necrosis/insufficiency
- result: lo cortisol and big hypotension
What area of cancer loves to metastasize to the adrenals?
Lung cancers
Pheochromocytomas present with what triad?
headache, diaphoresis, palpitations
Describe the treatment of a pheochromocytoma.
- first: Give phenoxybenzamine (irreversible alpha blocker)
- second: excise the adrenal gland
What ectopic area classically presents with a pheochromocytoma?
Bladder wall (episodic HTN when you piss)
Name 3 big pathological associations of pheochromocytoma.
- MEN 2A and 2B
- VHL disease (cerebellum+renal cell CA)
- NF1
Secondary adrenal insufficiency is characterized by what key physiologic difference?
A decrease in ACTH from anterior pituitary
How does SAI differ from PAI/Addison’s in presentation?
- NO hyperpigmentation
- NO hypoNa and hyperK
Describe the function of the cortisol-cortisone shunt.
- @hi levels, cortisol can hit mineralicorticoid receptors too.
- Kidneys have 11B-HSD2; converts cortisol to cortisone
- Liver has 11B-HSD1; converts cortisone back into cortisol
AME (apparent mineralicorticoid excess) syndrome is what?
- 11B-HSD2 deficiency
- symptoms identical to hyperaldosteronism
- can be induced by licorice
