Endocrine I Flashcards by Joseph Marvin

What does the anterior pituitary derive from?

Rathke’s pouch (ectodermal diverticulum)

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What does the posterior pituitary derive from?

Invagination of the hypothalamus (neuroectoderm)

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What gets secreted from the supraoptic nuclei?

ADH (AKA vasopressin)

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What increases ADH secretion?

Nicotine

Opiates

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What decreases ADH secretion?

Alcohol
ANP
Decreased serum osmolarity

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What does ADH do?

ADH binds to V2 → increased cAMP → increased aquaporin 2 to lumenal side

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Which 4 hormones have the same alpha subunit?

LH, FSH, hCG, and TSH

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ACTH and MSH (melanin stimulating hormone) are both originally part of what protein?

Proopiomelanocortin (POMC)

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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)

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Why are the fetal adrenals so important?

Cortisol is needed for type II pneumocytes to produce surfactant

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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)

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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)

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What is seen with 11b-hydroxylase deficiency?

HTN (d/t increased production of deoxycorticosterone)

Masculinization (d/t increased production of sex hormones)

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How does deoxycorticosterone cause HTN?

Deoxycorticosterone is a weak mineralocorticoid

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What is an easy way to remember the symptoms with steroid synthesis enzyme deficiencies?

1X → HTN

X1 → masculinization

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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

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How does cortisol suppress the immune system/inflammation?

Inhibits COX and PLA2

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What is the most common cause of Cushing syndrome?

Exogenous steroid use

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Besides exogenous steroid use, what are some other causes of Cushing syndrome?

Cushing disease
Ectopic ACTH
Cortisol-producing adrenal adenoma

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What is Cushing disease?

An ACTH producing pituitary adenoma

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What kind of cancer produces ectopic ACTH?

Small cell lung cancer

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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?

Cushing disease At a high enough dose there will be negative-feedback inhibition

What is the mnemonic for the symptoms of Cushing syndrome?

"BAM, CUSHINGOID''

What symptoms does the 'BAM' in "BAM, CUSHINGOID" represent?

Buffalo hump Amenorrhea Moon facies

What symptoms does the 'CUSH' in "BAM, CUSHINGOID" represent?

Crazy Ulcers Skin changes HTN

What symptoms does the 'ING' in "BAM, CUSHINGOID" represent?

Infection Necrosis of femoral head Glaucoma (and cataracts)

What symptoms does the 'OID' in "BAM, CUSHINGOID" represent?

Osteoporosis Immunosuppression Diabetes

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?

High Na+

A patient comes in with HTN, hypokalemia, and metabolic alkalosis. What is the likely diagnosis?

Hyperaldosteronism

What is it called when there is an aldosterone secreting tumor?

Conn Syndrome

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?

Leg weakness | Weight loss

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% malignant 10% bilateral 10% extra adrenal 10% calcify 10% children ```

What are some associations of pheochromocytoma?

MEN2A and MEN2B | NF1

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?

Alpha-blocker | 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?

Adrenal neuroblastoma

What is the primary symptom of an adrenal neuroblastoma?

Mild HTN

What are some associations of adrenal neuroblastoma?

N-myc oncogene Bombesin tumor marker Neurofilament stain Homer-Wright pseudorosettes

What is seen with MEN1? What is the mutation?

Diamond shape Parathyroid adenoma Pituitary adenoma Pancreatic tumor Menin has a loss-of-function

What is seen with MEN2A? What is the mutation?

Square shape Parathyroid hyperplasia Pheochromocytoma Medullary thyroid cancer Ret has a gain-of-function

What is seen with MEN2B? What is the mutation?

Triangle shape Medullary thyroid cancer Pheochromocytoma Ganglioneuromatosis Ret has a gain-of-function