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Endocrine and Reproductive Systems > CM- Adrenal Axis and Disease > Flashcards

CM- Adrenal Axis and Disease Flashcards

1
Q

What is the most common cause of Cushing syndrome?

A

Exogenous glucocorticoid administration [iatrogenic]

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2
Q

What is the most common cause of endogenous Cushing syndrome?

What are the 2nd and 3rd?

A

ACTH- secreting pituitary adenoma [Cushing disease]

followed by:

  1. adrenocortical adenomas/carcinoma
  2. ectopic ACTH syndrome
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3
Q

What are the 4 most common symptoms associated with excess cortisol [cushing syndrome]?

A
  1. truncal obesity
  2. fat pads in supraclavicular, dorsocervical
  3. hypertension/metabolic syndrome [high glucose, low K, high lipids]
  4. hirsutism and menstrual abnormalities in women
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4
Q

What are the 4 most specific symptoms for cushing sydrome?

A
  1. proximal weakness/myopathy
  2. easy bruising
  3. osteoporosis
  4. purple striae on abdomen
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5
Q

How is the diagnosis of Cushing syndrome made?

A
  1. increased cortisol in 24hr urine free cortisol

2. diurnal rhythm is lost [nocturnal saliva/serum cortisol is high]

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6
Q

You are evaluating a patient for glucocorticoid excess. They are critically ill. What should you do?

A

Reevaluate the patient when they are well, because it is normal for cortisol to elevate in critical illness

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7
Q

When evaluating a NON-critically ill patient for glucocorticoid excess, what is the next step?

A

Check the diurnal rhythm [cortisol should be high in the morning and decreased at night.

If the patient still has diurnal rhythm, it is pseudocushing state.

If the patient does not have diurnal rhythm, you should next evaluate if they are on iatrogenic steroids.

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8
Q

A patient presents with cortisol excess, no critical illness, but a disrupted diurnal rhythm. What is the next step for evaluation?

A

Ask about exogenous glucocorticoid use.

Yes = iatrogenic Cushing's 
No = look for endogenous cause
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9
Q

You have determined that a patient has endogenous Cushing. What 3 are ACTH dependent? Which is ACTH independent?

A

Dependent:

  1. pituitary adenoma
  2. ectopic ACTH
  3. ectopic CRH

Independent:
1. adrenal tumor

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10
Q

How can you determine the source of the problem in endogenous cushing syndrome?

A

First look at ACTH levels and cortisol levels.
If cortisol is high and ACTH is low, that means it is an adrenal tumor.

For ectopic, and pituitary tumors, the ACTH will be high and the cortisol will be high. To distinguish between those two, you administer a dexamethasone suppression test.

Pituitary tumor with high dose dexamethasone will have lower ACTH and lower cortisol
Ectopic tumors will still have high ACTH and cortisol

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11
Q

If the source of Cushing syndrome is found to be ACTH dependent, what is the next imaging/lab tests you should do?

If it is found to be ACTH independent what it the next imaging/lab test you do?

A

ACTH-dependent:
1. MRI of sella region because most common is pituitary adenoma
2. Inferior petrosal sinus sampling [IPSS] can localize the site of production
If not in the pituitary,
3. CT Chest/abdomen/pelvis

ACTH-independent:
1. do a CT of the adrenals

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12
Q

What signs(3)/symptoms(6) and labs (3) are suggestive of adrenal insufficiency [Addison’s disease]?

A
  1. weakness/fatigue [100%]
  2. anorexia [100%]
  3. nausea, vomiting, ab pain
  4. salt-craving
  5. postural dizziness
  6. arthralgias/myalgias

Signs:

  1. weight loss
  2. hyperpigmentation [increased POMC]
  3. hypotension

Labs:

  1. hyponatremia
  2. hyperkalemia
  3. anemia with eosinophilia [primary]
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13
Q

A patient comes to see you and says they have been feeling fatigued. This has progressed to nausea, vomiting and finally vascular collapse. What is the likely problem?

A

Addison’s [adrenal insufficiency]

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14
Q

How is adrenal insufficiency diagnosed?

A
  1. measure the 8am hormone levels
    - cortisol 85 is normal
    - ACTH [below 10 is low, above 100 is high]
    - Renin/Aldosterone [primary = high renin, low aldo, secondary = renin/aldo are both normal to high]
  2. cosyntropin stimulation test = give ACTH and then measure cortisol levels 45 minutes later. If it is above 18-20, then the problem is secondary.
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15
Q

In primary adrenal insufficiency, what is the ACTH level? What are the cortisol, aldo, and DHEA levels?
How do you test for primary adrenal insufficiency?

A

ACTH will be very high. Cortisol, aldosterone and DHEA will all be low.

Test for primary adrenal insufficiency with standard cosyntropin test:

  1. Give IV/IM 250 mg synthetic ACTH [cosyntropin]
  2. measure serum cortisol 30-60 min later
  3. normal: cortisol >18 at any point in the test
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16
Q

What are the 2 main causes of secondary adrenal insufficiency?
What is the ACTH, cortisol, DHEA and aldosterone levels?
Why is the cosyntropin test not always reliable for secondary?

A

Two main causes of secondary AI:

  1. pituitary lesion
  2. pharmacological suppression

ACTH is low, cortisol and DHEA are low, and aldosterone is high [because it is not under pituitary control]

Cosyntropin test is not always reliable because ACTH will stimulate adrenals and give a normal result >18 despite an abnormal HP axis

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17
Q

What are the 4 tests used to diagnose secondary adrenal insufficiency?

A
  1. insulin induced hypoglycemia
  2. overnight metyrapone test
  3. low dose cosyntropin test
  4. measure DHEA-S
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18
Q

Describe the insulin induced hypoglycemia test for secondary adrenal insufficiency.
What does it test?
What would a normal test show?
What are the dangers of this test?

A

It tests the entire axis, also GH and prolactin reserve.
You give the patient insulin to make them hypoglycemic. Cortisol works against insulin, so a normal test would have a cortisol peak >18-20.

Dangers: unpleasant, requires careful supervision, can precipitate seizures, coronary syndromes

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19
Q

Describe the overnight metyrapone test.
What is the mechanism by which this test works?
What is a normal test? What is required to fail the test?

A

This test is used to reduce cortisol to see if there will be an increase in ACTH secretion.

  1. give metyrapone at 11pm with a snack
  2. measure the accumulation of 11-deoxycortisol and cortisol

Metyrapone inhibits 11B-hydroxylase [the enzyme that catalyzes the last step in the synthesis of cortisol]. This releases feedback inhibition so in the morning ACTH should be high and cortisol low.

Normal test: 11-deoxycortisol >7
To fail the test cortisol needs to be less than 5

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20
Q

Why is low dose cosyntropin test used for secondary adrenal insufficiency?

A

Secondary adrenal insufficiency can pass standard cosyntropin tests, but will fail the low dose test.

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21
Q

To evaluate secondary adrenal insufficiency, you can measure DHEA-S levels. Normal values of >85 rule out ____________________ but do not exclude_____________________.

A

Normal DHEA rules out acquired cortisol deficiencies but does NOT exclude CAH

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22
Q

What are the etiologies associated with primary adrenal insufficiency?

A
  1. Autoimmune [+21OHase antibodies]
  2. TB, CMV, histo and fungals
  3. infiltrative [hemochromatosis, amyloidosis]
  4. destruction [surgical, Waterhouse-Friderichsen]
  5. developmental - adrenal hypoplasia
  6. enzyme deficiencies- CAH [21 hydroxylase deficiency, 17 and 11 hydroxylase deficiencies]
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23
Q

What are the etiologies of secondary adrenal insufficiency?

A
  1. autoimmune- lymphocytic, granulomatous hypophysitis
  2. infection -TB
  3. infiltrative- sarcoidosis, hemochromatosis
  4. destruction- tumors, surgical, radiation
  5. midline defects in development
24
Q

What is treatment for adrenal insufficiency when it is:

  1. acute
  2. stable
  3. sick
A
  1. IV fluid and high dose of glucocorticoids
  2. 20mg hydrocortisone in the morning and 10 at night with adequate salt intake
  3. double doses for inability to defend volume state
25
Q

What are the clinical features of mineralocorticoid excess [Conn}?

A
  1. metabolic alkalosis
  2. hypokalemia with inappropriate kaluresis
  3. hypomagnesemia
  4. hypertension
  5. absence of edema
  6. patients are younger than normal hypertensives
26
Q

What is secondary aldosteronism?

A

When renin is not suppressed [RAAS is what is causing the aldosterone excess].

27
Q

Who should be screened for primary aldosteronism?

A
  1. hypertension with low K [<3.5]
  2. patients with resistant hypertension
  3. hypertension below the age of 40
  4. hypertension and a known adrenal mass
28
Q

When screening for primary aldosteronism, what is it important to discontinue before the testing?

A
  1. spironalactone, epleronone 4-6wks before
  2. ACEI, ARB
  3. diuretics
  4. NSAIDS
  5. antihypertensives

You can use alpha-blockers and verapamil and low dose b-blockers

29
Q

What are the 2 main screening tests for primary aldosteronism?

A
  1. 24hr Urine Na and K [K excretion >30 with concomitant Na excretion >100 when serum K is under 3.5 is + for mineralocorticoid excess]
  2. Plasma aldosterone conc/plasma renin activity ratio [PAC/PRA]. Renin and aldosterone should track in parallel, so suppressed PRA with high or normal PAC is good evidence of aldosterone autonomy.
    PAC/PRA >35 is diagnostic of hyperaldosteronism and >15 is compatible
30
Q

What are the 5 confirmatory tests for primary aldosteronism?

A
  1. 24hr Urine Aldosterone on high salt diet
  2. saline infusion test
  3. fludrocortisone suppression test
  4. in adolescent patient measure DOC for 17,11hydroxylase deficiencies
  5. dexamethasone suppression test for GRA
31
Q

When is the 24 hour Urine aldosterone on a high salt diet test given?
How does it work?

A

It is given when there is a suspicion of primary aldosterone excess.

  1. give patient high salt (>120mEq/day,over200 is best) for 3days
  2. Aldo secretion in the urine >14microns/day with a urine Na of over 120 confirms hyperaldosteronism
32
Q

Describe how the saline infusion test is performed. What results are indicative of hyperaldosteronism?

A

Infuse patients with normal saline over 4 hours [2L at 500ml/hr]

If plasma aldosterone is over 10ng/dl at the end of the test, this confirms hyperaldosteronism

33
Q

Describe the steps of the fludrocortisone suppression test.

A
  1. ingest high Na diet and take 0.2mg 9B-fludrocortisone acetate for 3 days
  2. During the last day get a 24hr urine aldosterone level, and a plasma aldosterone level.

Urine> 8 and plasma >8.5 is considered diagnostic for hyperaldosteronism

34
Q

If you do confirmatory tests like 24hr urine aldo after high salt diet, saline infusion test, and fludrocortisone suppression test, and you believe there is hyperaldosteronism, what ancillary tests should be performed?

A
  1. urinary free cortisol to see if other parts of the adrenals are affected
  2. if there is family history screen for GRA [glucocorticoid remediable aldosteronism]
  3. serum DOC, urine (THF+THFa)/THE
  4. 17 or 11 b-hydroxylase deficiency
  5. Dexamethasone suppression test for GRA
35
Q

Describe the dexamethasone suppression test for GRA.

A
  1. take dexamethasone for 3 days and collect 24 hour urine for aldo.
  2. on the third day obtain a plasma aldo 2hr after the final dose

Urine excretion <4 demonstrates suppressability of aldosterone with glucocorticoid [this confirms GRA because it shows that aldosterone is sensitive to ACTH]

36
Q

Which tends to have worse hypertension, hypokalemia and higer levels of aldosterone, APA or IHA?

A

APA [aldosterone producing adenoma]

37
Q

What 2 techniques are used to localize masses to distinguish aldosterone producing adenomas from idiopathic hyperaldosteronism?
What are the pros and cons of each technique?

A
  1. Adrenal CT
    - Pro= can detect masses over 5mm.
    - Con = cannot tell if masses are functional
  2. Adrenal Vein Sampling
    - Pro:GOLD STANDARD
    - Con : expensive, invasive, technically difficult
38
Q

Describe the process of adrenal vein sampling.

A
  1. Infuse ACTH just prior to the procedure to stimulate the cortex of the adrenals
  2. get 1-2 blood samples from both adrenal veins
  3. check cortisol levels [which should be elevated from the cosyntropin] to ensure you are actually in the adrenal vein
  4. Compare aldo/cortisol ration from the two sides
  5. > 4:1 difference confirms unilateral aldosterone production and the adrenal should be removed.
39
Q

What is therapy for aldo producing adenomas and primary adrenal hyperplasia?

A
  1. unilateral adrenalectomy

2. spironolactone or eplerenone

40
Q

How is idiopathic hyperaldosteronism treated?

A
  1. Na restriction
  2. spironolactone or eplernone
  3. amiloride
41
Q

What is the treatment for GRA?

A

It is glucocorticoid remediable aldosteronism, so give dexamethasone [It will suppress ACTH]

42
Q

In general ________________________ includes both glucocorticoid and mineralcorticoid deficiencies, whereas ______________________ is limited to glucocorticoid deficiencies.

A

Primary adrenal insufficiency = both

Secondary adrenal insufficiency = gluco

43
Q

What is the disorder where glucocorticoid synthesis is completely normal, but aldosterone synthesis is impaired?
What is the inheritence pattern?
What is the treatment?

A

It is an autosomal recessive mutation in aldosterone synthase [p450aldo].

Treatment is salt and volume replacement and occassionally the aid of 9B-fludrocortisone acetate [a synthetic mineralocorticoid]

44
Q

In general, intra-adrenal pheochromocytomas make mostly _______________.
Extra-adrenal make mostly _________________ and glomus tumors of the head and neck make mostly __________.

A

Adrenal = epinephrine

Paraganglioma {extra-adrenal} = norepinephrine

Glomus tumors = dopamine

45
Q

COMT [catecholamine O-methyl transferase] converts:
Dopamine –>?
Norepi–>?
Epi–> ?

A

Dopamine to methoxytyramine
NE to normetanephrine
E to metanephrine

46
Q

Why are metanephrines more specific that catecholamines when diagnosing tumors?

A

COMT is normally produced in the peripheral tissue but there is a delay in their formation from catecholamines derived from symp. nerves/adrenals.

COMT is usually contained in tumors, thus metanephrines are constantly being produced

47
Q

Monoamine oxidase converts:

methoxytyramine –>

normetanephrine –>

metanephrine–>

A

Methoxytyramine –> HVA [homovanillic acid]

Normetanephrine AND metanephrine –> VMA [vanillylmandelic acid]

48
Q

A man has been having spells of BP elevation with tachycardia, headache, generalized sweating and blanching of the face. Each spell lasts 10 minutes to an hour.
He says the spells are usually brought on by exercise, strenuous activity or sometimes urinating.

What is the likely cause?

A

Pheochromoctytoma

49
Q

What are the 5 Ps of pheo?

A
  1. Pressure- sudden spikes in BP
  2. Pain- headache [throbbing and acute]
  3. Perspiration - drenching
  4. Palpitations
  5. Pallor - peripheral vasoconstriction during spells

In addition there is weight loss, tremor, hyperglycemia, and hypercalcemia

50
Q

Familial pheochromocytoma with medullary thyroid cancer is associated with mutations in what?

A
  1. MEN2A- MTC, hyperPTH, RET mutation

2. MEN2B - MTC, marfanoid habitus, mucosal neuroma, RET

51
Q

Familial pheo without medullary thyroid cancer is associated with what?

A

VHL- retinal angiomata, polycythemia, cerebellar hemangioblastomas

52
Q

What are the pros and cons of using urine catecholamines and metabolites to diagnose pheo?

A

In this test you collect 24hr urine for fractionated catecholamines and metanephrines and creatinine.

Pros:
1. symptomatic pheo patients will have PROFOUND elevations >5x normal in proportion to symptoms

Cons:

  1. modest elevations could be essential hypertension and not pheo
  2. False + for sleep apnea, clonidine, TCA use
53
Q

What are the pros and cons of plasma catecholamines and metabolites?
Who should this test be reserved for?

A

Measures plasma metanephrines.

Pros:
1. drawing blood can elevate catecholamines but metanephrine rise is less common unless they have a tumor producing metanephrines

Cons:
1. slight normetanephrine rise is common, but metanephrine rises must be taken seriously

This test should be reserved for:

  1. high probablility of disease [MEN-meta, VHL=normeta]
  2. when you dont think the patient has pheo but may have sleep apnea
54
Q

What are the 2 goals of pre-op for pheochromocytomas?

What are the 4 meds that help achieve this?

A
  1. block excess catecholamine action
  2. volume replace the patient to prevent circulatory collapse
  3. alpha -blocker - pheoxybenzamine for severe cases and dixazosin for less severe
  4. salt- oral or IV to help reload volume - add it as long as the a-blockade is done gradually
  5. metyrosine - blocks catecholamine synthesis directly
  6. b-blocker AFTER alpha blockade and volume repletion
55
Q

If you see an incidental adrenal nodule on a CT, what initial tests should be done?

A
  1. routine PE and BP
  2. screen for Cushing with dexamethasone suppression test
  3. screen for pheo with plasma or urinary metanephrines
  4. screen for primary hyperaldosteronism if hypertensive with hypokalemia [RAAS]
56
Q

What is the criteria for followup based on size and characteristics of an adrenal mass on CT?

A

If the Hounsfield score is <0 it is lipid rich [cortical adenoma or myelolipoma] and malignancy is excluded.

Masses over 3cm has a high probability of hormone excess and should be removed.
Everyone gets a follow-up scan at 6months to see if its growing

Endocrine and Reproductive Systems (27 decks)

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