Flashcards in Endocrine I Deck (54):
What does the anterior pituitary derive from?
Rathke's pouch (ectodermal diverticulum)
What does the posterior pituitary derive from?
Invagination of the hypothalamus (neuroectoderm)
What gets secreted from the supraoptic nuclei?
ADH (AKA vasopressin)
What increases ADH secretion?
What decreases ADH secretion?
Decreased serum osmolarity
What does ADH do?
ADH binds to V2 → increased cAMP → increased aquaporin 2 to lumenal side
Which 4 hormones have the same alpha subunit?
LH, FSH, hCG, and TSH
ACTH and MSH (melanin stimulating hormone) are both originally part of what protein?
Sheehan syndrome happens when there is hypo perfusion to the pituitary after labor/delivery. What symptoms would be expected with this condition?
Agalactorrhea (no oxytocin)
Amenorrhea (no FSH/LH)
Secondary hypothyroidism (no TSH)
Why are the fetal adrenals so important?
Cortisol is needed for type II pneumocytes to produce surfactant
What are the symptoms of 21a-hydroxylase deficiency?
Increased ACTH (d/t inability to produce cortisol)
Hypotension and salt wasting ( d/t inability to produce mineralocorticoids)
Masculinization (d/t increased production of sex hormones)
What is seen with 17a-hydroxylase deficiency?
Phenotypic female who is unable to mature (d/t inability to produce sex hormones and cortisol)
HTN (d/t increased production of mineralocorticoids)
What is seen with 11b-hydroxylase deficiency?
HTN (d/t increased production of deoxycorticosterone)
Masculinization (d/t increased production of sex hormones)
How does deoxycorticosterone cause HTN?
Deoxycorticosterone is a weak mineralocorticoid
What is an easy way to remember the symptoms with steroid synthesis enzyme deficiencies?
1X → HTN
X1 → masculinization
When is cortisol (a glucocorticoid) released?
In response to stress:
Up-regulates apha1 arteriole receptors
Increases gluconeogenesis (and similar)
Suppresses immune system and inflammation
Decreases bone formation
How does cortisol suppress the immune system/inflammation?
Inhibits COX and PLA2
What is the most common cause of Cushing syndrome?
Exogenous steroid use
Besides exogenous steroid use, what are some other causes of Cushing syndrome?
Cortisol-producing adrenal adenoma
What is Cushing disease?
An ACTH producing pituitary adenoma
What kind of cancer produces ectopic ACTH?
Small cell lung cancer
What CAN'T you confuse small cell lung cancer's production of ACTH with?
Squamous cell lung cancer's production of PTH-like protein
What should be seen in a normal person with low-dose and high-dose dexamethasone tests?
Cortisol normally decreases with dexamethasone administration
Dexamethasone tests are done, and cortisol remains high after both tests. What is the cause of the Cushing syndrome?
Either ectopic ACTH or a cortisol-producing adrenal adenoma
No matter how much synthetic glucocorticoid is given, there will not be a negative-feedback inhibition
Dexamethasone tests are done, and cortisol remains high after the low-dose but lowers after the high-dose. What is the cause of the Cushing syndrome?
At a high enough dose there will be negative-feedback inhibition
What is the mnemonic for the symptoms of Cushing syndrome?
What symptoms does the 'BAM' in "BAM, CUSHINGOID" represent?
What symptoms does the 'CUSH' in "BAM, CUSHINGOID" represent?
What symptoms does the 'ING' in "BAM, CUSHINGOID" represent?
Necrosis of femoral head
Glaucoma (and cataracts)
What symptoms does the 'OID' in "BAM, CUSHINGOID" represent?
What is the effect of aldosterone (mineralocorticoid)?
Activates ENaC and ROMK
What increases the secretion of aldosterone?
High K+ (ROMK secretes K+)
Low Na+ (ENaC reabsorbs Na+)
ATII (reabsorption of water)
What decreases the secretion of aldosterone?
A patient comes in with HTN, hypokalemia, and metabolic alkalosis. What is the likely diagnosis?
What is it called when there is an aldosterone secreting tumor?
Why does metabolic alkalosis occur with hyperaldosteronism?
H+/K+ ATPase tries to correct the hypokalemia...which then decreases serum H+ (which is the same thing as saying increasing the pH)
What is a secondary cause of hyperaldosteronism?
Excess renal renin production d/t perceived low volume...like with stenotic renal arteries
A patient presents with hypotension, hyponatremia, hyperkalemia, and skin hyperpigmentation. What is the likely diagnosis?
Addison's disease (primary adrenal insufficiency)
What is the likely cause of Addison's disease?
Addison's is usually autoimmune
What are some situations in which the there can be a hemorrhage in the adrenals?
Waterhouse-Friderichsen syndrome can be occur with severe meningococcal sepsis or DIC
What is seen with secondary adrenal insufficiency?
What causes tertiary adrenal insufficiency?
Sudden withdrawal of corticosteroids
A patient comes in concerned about periodic headaches, sweats, and rapid heart rate. What is the likely diagnosis? What else is likely seen during these episodes?
This patient likely has a pheochromocytoma
There would also be HTN during these episodes
What is seen on UA with a pheochromocytoma?
Catecholamine breakdown products (metanephrine, normetanephrine, vanillylmandelic acid [VMA])
What are the rules of 10 for pheochromocytoma?
10% extra adrenal
What are some associations of pheochromocytoma?
MEN2A and MEN2B
Besides catecholamines, what else can be secreted by a pheochromocytoma? What other cancers can secrete this?
A pheochromocytoma can secrete EPO
Renal cell carcinoma, Hemangioblastoma, and Hepatocellular carcinoma can also secrete EPO
What drug is used to treat HTN with a pheochromocytoma?
(A beta-blocker would cause unopposed alpha-receptor activity...like with cocaine addicts)
What is a tumor of sympathetic ganglion cells typically seen in children?
What is the primary symptom of an adrenal neuroblastoma?
What are some associations of adrenal neuroblastoma?
Bombesin tumor marker
What is seen with MEN1? What is the mutation?
Menin has a loss-of-function
What is seen with MEN2A? What is the mutation?
Medullary thyroid cancer
Ret has a gain-of-function