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Block 10 Week 2 > Usera: Endocrine Pathology > Flashcards

Usera: Endocrine Pathology Flashcards

1
Q

What are the three zones of the adrenal cortex, and what does each layer produce?

A
  1. zona glomerulosa: mineralocorticoids –> aldosterone
  2. zona fasciculata: glucocorticoids –> cortisol
  3. zona reticularis: sex hormones
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2
Q

The adrenal medulla is derived from (blank) and produces (blank)

A

neural crest; catecholamines (tyrosine –> DOPA –> dopamine –> NE –> epinephrine)

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3
Q

List three ways in which you can get acute adrenocortical insufficiency

A
  1. abrupt withdrawal of corticosteroids (most commonly)
  2. anticoagulation therapy
  3. Waterhouse-Friderichsen Syndrome
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4
Q

Bilateral adrenal hemorrhage
Associated with Neisseria Meningitidis septicemia
Endotoxic shock with DIC

A

Waterhouse-Friderichsen syndrome

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5
Q

What are 3 components of Waterhouse-Friderichsen syndrome?

A

bilateral hemorrhage necrosis of adrenal glands
associated with N. meningitidis septicemia
endotoxic shock with DIC

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6
Q

What are 5 ways in which you can get CHRONIC adrenocortical insufficiency?

A
  1. autoimmune destruction (80%)
  2. Infectious - TB (most common cause in developing world)
  3. mets from lung cancer (or RCC)
  4. adrenogenital syndrome
  5. AIDS
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7
Q

What are the findings in chronic adrenal insufficiency?

A

weakness (no cortisol –> breakdown of muscles)
hypotension (no mineralocorticoids)
hyperpigmentation (increased ACTH)

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8
Q

What are the lab findings in chronic adrenal insufficiency?

Sodium?
Potassium?
H+?

A 
low sodium
high potassium (principal cells are not exchanging Na+/K+)
metabolic acidosis (H+ not being dumped along with K+)
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9
Q

What happens to fasting glucose levels in chronic adrenal insufficiency? Why?

A

fasting hypoglycemia, because you are lacking cortisol, which is gluconeogenic

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10
Q

What happens to ACTH levels in chronic adrenal insufficiency? What happens when you administer an ACTH stimulation test?

A

they increase, because you aren’t making cortisol; no response to ACTH stimulation test

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11
Q

Describe how the metyrapone test works for diagnosing adrenal insufficiency

A

Metyrapone inhibits 11-beta hydroxylase, and prevents cortisol synthesis. When administered, it should increase ACTH secretion and increase steroid precursors. If there is an increase in ACTH but NO increase in 11-deoxycortisol, this indicates adrenal insufficiency.

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12
Q

What enzymes are necessary to take pregnenolone to aldosterone (mineralocorticoids)?

A

21 & 11
21 hydroxylase
then 11 hydroxylase to make more complex mineralocorticoids

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13
Q

What enzymes are necessary to take pregnenolone to cortisol (glucocorticoids)?

A

17, 21, & 11

17 alpha-hydroxylase takes pregnenolone to 17-hydroxypregnenolone
then, you need 21 hydroxylase and 11 hydroxylase to form cortisol

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14
Q

What enzymes are necessary to take pregnenolone to the sex hormones?

A

17

17 alpha-hydroxylase takes pregnenolone to 17-hydroxypregnenolone

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15
Q

What are the three autosomal recessive disorders of adrenal biosynthetic enzymes that can lead to adrenal hyperplasia? Which is the most common?

A

21 hydroxylase deficiency **most common
11 hydroxylase deficiency
17 hydroxylase deficiency

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16
Q

Congenital adrenal hyperplasia occurs when there are disorders in adrenal biosynthesic enzymes. What effect do these disorders have?

A

increase ACTH, bc no negative feedback
accumulation of enzymes proximal to enzyme block
blockage in 21-hydroxylase or 11-hydroxylase increases 17-ketosteroids & testosterone

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17
Q

What should you do if you suspect adrenogenital syndrome (congenital adrenal hyperplasia?

A

chromosomal analysis
test serum 17-hydroxyprogesterone levels - increased in 21 and 11-hydroxylase deficiency
decreased in 17-hydroxylase deficiency

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18
Q

What can 21-hydroxylase deficiency cause in males & females? In neonates?

A

neonates: hyponatremia, hyperkalemia, hypovolemia, females with congenital ambiguity (clitoral enlargement)
rapid growth as children, but short stature as adults
nonclassic form presents later in life: precocious puberty in males & hirtuism or menstrual irregularities in females

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19
Q

Decrease in cortisol & sex hormones
Salt retainers because weak mineralocorticoids are increased (leading to HTN & mild hypokalemia)
Females: delayed menarche & secondary sexual characteristics
Males: pseudohermaphroditism

A

17 hydroxylase deficiency

**17 hydroxylase is necessary to take pregnenolone to both glucocorticoids & sex hormones

20
Q

What will you see physically in 17-hydroxylase deficiency?

A

clitoris hypertrophy
poor development of labial structure
no palpable gonad

21
Q

What things can cause cushing syndrome (adrenocortical hyperfunction)?

A

prolonged corticosteroid use
Cushing disease
hyperfunctional adrenal adenoma
ectopic ACTH production

22
Q

Hyperaldosteronism - also due to a hyperfunctional adrenal adenoma

A

hyperaldosteronism

23
Q

Signs & symptoms of cushing syndrome and why do you see them?

A

Weight gain & round face –> hyperglycemia –> secondary hyperinsulinism –> fat deposition in face, nape, and trunk
Hirsutism –> due to increased androgens
Abdominal stria –> weakened collagen & rupture of blood vessels
Diastolic hypertension –> increased mineralocorticoids
Muscle weakness –> breakdown of muscle for gluconeogenesis

24
Q

What will happen to the following lab values in cushing syndrome?

urine cortisol?
blood sugar?
H+ acid/base status?

A

increased urine free cortisol
hyperglycemia
hypokalemic metabolic alkalosis

25
Q

What causes Conn’s syndrome?

A

aldosterone secreting adrenal adenoma (in zona glomerulosa)

26
Q

Clinical findings of Conn’s syndrome?

A

diastolic hypertension

muscle weakness

27
Q

Lab findings in Conn’s syndrome?

A

hypernatremia
hypokalmia
alkalosis
decreased plasma renin

28
Q

Catecholamine secreting tumor of the adrenal medulla chromaffin cells (epi & NE)

A

pheochromocytoma

29
Q

What is the rule of 10’s for pheochromocytoma?

A

10% are bilateral
10% are malignant (90% benign)
10% located outside of the renal medulla (ex: bladder wall)

30
Q

Signs & symptoms of pheochromocytoma?

A 
episodic or sustained hypertension
headache
palpitations
tachycardia
sweating
anxiety
chest pain
constipation

**increased catecholamines

31
Q

How do you diagnose Cushing syndrome?

A

dexamethasone suppression test

  • *low dose of dexamethasone should suppress ACTH in normal individuals
  • *high dose of dexamethasome can suppress cortisol in cushing DISEASE, but not other forms
  • *ACTH coming from pituitary ACTH secreting cells can be suppressed, but not from ectopic sites or adrenal adenomas
32
Q

This form of pheochromocytoma is extramedullar & only produces norepinephrine, because it lacks phenylethamine-N-methyltransferase

A

paraganglioma

33
Q

What 3 diseases are associated with pheochromocytomas?

A

neurofibromatosis type I
MEN 2A and 2B
von Hippel-Lindau disease

34
Q

What is the best confirmatory test for diagnosing pheochromocytoma? What test has the best sensitivity?

A

plasma serum free metanephrines - best confirmatory test
increased 24-hour urine metanephrines - best sensitivity

**you can also test 24-hour urine VMA

35
Q

What will you find in the urine of patients with pheochromocytoma?

A

increased urine metanephrine and normetanephrine

both of these products are broken down into vanillylmandelic acid, so you will get an increase in urine VMA too

36
Q

What other lab findings will you have in pheochromocytoma?

A

no suppression with clonidine
hyperglycemia
neutrophilia

37
Q

Why does removal of a pheochromocytoma require pre-op stabilization with an alpha-inhibitor & beta-blocker

A

because during surgical excision, catecholamines may leak into the bloodstream

**PBZ is an irreversible alpha blocker to prevent hypertensive crisis

38
Q

Malignant neoplasm of post-ganglionic sympathetic neurons
Small round blue cell tumor
Common in children less than 5 years old
N-MYC amplication in 20-30% of cases, marker of aggressive behavior
70% are metastatic at diagnosis
Prognosis good if less than 1 year old or hyperdiploid
Prognosis bad if greater than 1 year or 1p deletion
Large palpable abdominal mass

A

Neuroblastoma

39
Q

Who gets neuroblastomas?

A

common in children less than 5yo

40
Q

What genetic abnormality is associated with neuroblastomas are is a marker of aggressive behavior?

A

N-MYC

41
Q

What makes the prognosis better for neuroblastoma? What makes it worse?

A

good: less than 1yo, hyperdiploid
bad: older than 1yo, 1p deletion

42
Q

70% of neuroblastomas will have (blank) at diagnosis

A

metastasized

43
Q

What does neuroblastoma look like histologically?

A

small round blue cell tumor

44
Q

How will neuroblastoma present physically?

A

large, palpable abdominal mass

45
Q

How can you diagnose neuroblastoma?

A

increased urine VMA and HVA
large palpable abdominal mass
small round blue cell tumor on histology

46
Q

What is the overall survival like for neuroblastoma?

A

40%

Block 10 Week 2 (8 decks)

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