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Endocrinology Week 2 > Lecture 16: Adrenal Pathophysiology > Flashcards

Lecture 16: Adrenal Pathophysiology Flashcards

1
Q

What is Cushing’s syndrome?

A

Defined as EXCESS cortisol secretion

Regardless of cause or source

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2
Q

What is the most common cause of Cushing’s syndrome?

A

Iatrogenic from exogenous glucocorticoid use

ACTH-INDEPENDENT

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3
Q

What are the pathophysiologic derangements of the HPA axis?

A
  1. loss of diurnal variation of cortisol secretion
  2. Autonomy from central ACTH control
    • los of response to negative feedback
  3. excess cortisol secretion
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4
Q

What are the two types of Cushing’s Syndrome?

A
  1. ACTH-Dependent

2. ACTH-independent

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5
Q

What are the causes of ACTH-dependent Cushing’s?

A
  1. Cushing’s disease (pituitary adenoma) 68% of patients
  2. Ectopic ACTH syndrome
  3. Ectopic CRH syndrome
  4. Factitious ACTH administration
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6
Q

What are the causes ACTH-independent Cushings?

A
  1. Iatrogenic/factitious
  2. adrenal adenoma
  3. adrenal carcinoma
  4. micro/macronodular hyperplasia
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7
Q

What does dexamaethasone do to the ACTH?

A

It suppresses it
Normal pituitary tissue should not secrete ACTH
So you should have low cortisol after administration

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8
Q

What are the sign and symptoms of Cushings?

A
  1. Gluconeogensis stmulated so HYPERglycemia
  2. Increased lipogenesis from increased insulin
  3. INSULIN RESISTANCE
  4. Protein metabolism
    • catabolism of gluconeogenesis
  5. Fat deposition in suprclavicular fossa
  6. Immunity is impaired
  7. Increased clotting factors
  8. Cataract formation
  9. OSTEOPOROSIS
  10. Wide variation of psychiatric disturbances
    • depression, psychosis
  11. integument, acne, streaks in skin
  12. cardiomyopathy, hypertension
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9
Q

Where is fat deposition in Cushing’s?

A

Round face DEWLAP (in chin)
Fat pads (supraclavicular fat pads)
Buffalo humps

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10
Q

What are the mineralocorticoid and androgen effects in Cushings?

A
  1. HTN and HYPOkalemia
  2. testosterone increase in females
  3. menses is abnormal
  4. virilization
    Onl in ACTH DEPENDENT because ACTH fucks
    With androgens
    Bilateral adrenal hyperplasia
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11
Q

If you suspect patient with Cushing’s, what would You need to do first?

A

You need to make sure they are not using exogenous cortisol

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12
Q

How do you measure Cushings?

A
  1. measure late night salivary cortisol
  2. 1 mg dexamethasone suppression test
  3. 24 urinary free cortisol
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13
Q

What is the 1 mg dexamethasone suppression test?

A

The DST indicates inappropriate cortisol secretion
Does not indicates source
Dex is taken by patient at 11pm and cortisol is measured at 8am
Normal test = <2 mcg/dl after Dex
Dexamethasone = cortisol in that it downregulates (or should downregulate) ACTH

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14
Q

What does it mean to have a positive dex test?

A

It means there is an autonomous adrenal tissue that is generating cortisol
ACTH adenoma will continue to stimulate adrnals
Loss of negative feedback control
Could be ACTH adenoma

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15
Q

You suspect Cushing’s in a patient. Their urine cortisol is elevated and cortisol is elevated after DST. ACTH levels are normal. What is source of Cushing’s?

A

Pituitary Adenoma (cushing’s disease)

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16
Q

If you have normal ACTH and high cortisol, you have?

A

Pituitary adenoma

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17
Q

If you have high ACTH and high cortisol, you have?

A

Ectopic ACTH excess

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18
Q

If you have low ACTH and high cortisol, you have?

A

Adrenal tumor

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19
Q

If iatrogenic glucocorticoids, what si ACTH level?

A

ACTH should be suppressed by iatrogenic cortisol

20
Q

What is being burned when you have too much cortisol?

A

Glucose from gluconeogenesis (so that’s why you lose muscle)

21
Q

How long does it take hypercortisolism to resolve?

A

12 months

Psychiatric complications can remain

22
Q

What is primary adrenal failure?

A 
Addison’s disease
Typically 90% of cortex is destroyed
Elevated ACTH concentrations
Course can be acute or indolent depending on cause
All adrenal hormones can be lost
23
Q

What type of symptoms would you expect in primary adrenal failure?

A

Symptoms consistent with both mineralocorticoid and glucocorticoid deficiency

i. HYPOnatremi
ii. HYPERkalemia
iii. HYPOtension
iv. HYPERpigmentation

24
Q

What are the clinical characteristics of primary adrenal failure?

A
  1. hyperpigmentation from increased ACTH, increasing melanin
  2. EXHAUSTED (real fatigue)
  3. Weight loss
  4. muscle or joint pains
  5. Fatigue
  6. Nausea, abdominal pain
  7. hypoglycemia can occur
25
Q

What are the etiologies of primary adrenal insufficiency?

A
  1. Autoimmune destruction of adrenal cortex: 60%
  2. Infectious: TB, fungus, HIV (CMV, MAI, KS)
  3. Bilateral hemorrhage/Infarction: anticoagulants, trauma, embolic disease, meningococcemia (Waterhouse-Friderichsen syndrome)
  4. Metastatic cancer
  5. Drugs: aminoglutethimide, ketoconazole, etomidate; rifampin, phenytoin (increase cortisol metabolism)
26
Q

Which of the following clinical/lab findings would you expect with Addison’s?

A

HYPOnatremmia and HYPERkalemia

That’s because glomerulosa and fasciculate is fucked

27
Q

How do you diagnose adrenal insufficiency?

A
  1. early AM cortisol and ACTH concentration (when shit is supposed to be highest)
  2. if early am cortisol <5mcg/dl with an elevated ACTH very likely primary adrenal insufficiency
  3. Cosyntropin stimulation testing, IM injection of synthetic ACTH. Cortisol measured 30 to 60 min later
28
Q

What is cosyntropin testing?

A

Cosyntropin is synthetic ACTH
Cortisol should be higher
If serum cortisol is >20 mcg/dl, then it cant be adrenal failure cuz ACTH worked

29
Q

How do you treat Addisons?

A

Give dexamethasone first because it will NOT INTERFERE with cortisol assay
Initial treatment

30
Q

What is an addisonian (adrenal) crisis)?

A
  1. Defined as acute deficiency in cortisol and mineralocorticoids
  2. Can be life threatening
  3. Often masquerades as other conditions i.e. sepsis, acute abdomen
  4. HYPOtension, shock
  5. Fatigue, weakness, malaise
  6. Fever, lethargy
  7. Abdominal pain, nausea, vomiting
  8. Anorexia
  9. Hypoglycemia
31
Q

What is the short term treatment of addisonian crisis ?

A
  1. 1-3 liters of saline IV over 12-24 hours
  2. Dexamethasone 4mg IV
  3. Monitor electrolytes
  4. Monitor blood pressure
32
Q

What is vitiligo?

A

A condition that causes depigmentation of sections of skin

-loss of brown color from areas of skin, resulting in irregular white patches

33
Q

What is the association between Addison’s and autoimmune disorders?

A

Half of persons with autoimmune adrenalitis have at least one other autoimmune disorder

34
Q

What are the symptoms of primary hyperaldosteronism?

A
  1. Hypertension
  2. Hypokalemia (muscle weakness)
  3. Mild hypernatremia
  4. Metabolic alkalosis
35
Q

Can a patient have hyperaldosteronism AND normal serum potassium?

A

Yes
While potassium wasting is common in mineralocorticoid excess syndromes but is not absolute; and patients may have hyperaldosteronism and normal serum potassium

36
Q

What are the characteristics of androgen excess?

A
  1. in women, hirsutism, male pattern baldness, menstrual irregularities
  2. gonadotropin secretion is disrupted in men
  3. adrenal adenomas rarely cause androgen excess, they are efficient at secreting cortisol
    Cushing’s syndrome can cause elevations in testosterone and DHEA-S
37
Q

What is a pheochromocytoma?

A

Tumor that secretes excess catecholamines (epinephrine)
-arises from chromaffin cells
Feeling of impending doom

38
Q

Which of the following would you screen for primary hyperaldosteronism? EXAM QUESTION

A
  1. Persons under 30 with hypertension, no obesity or family history
  2. Persons with unexplained hypokalemia
  3. Persons with resistant hypertension
  4. Persons with an adrenal incidentaloma and hypertension
39
Q

What are the causes of hyperaldosteronism?

A
  1. Adrenal adenoma producing aldosterone
  2. Bilateral adrenal hyperplasia
  3. elevated aldosterone:renin ratio
  4. needs to demonstrate it after salt lpad
40
Q

If you have bilateral adrenal hyperplasia, how do you treat?

A

Mineralocorticoid antagonists

41
Q

If you have unilateral adenoma, what do you do?

A

Surgical resection

42
Q

What is the most common cause of addisons? EXAM QUESTION

A

Autoimmune destruction of adrenal cortex

43
Q

In pituitary Cushing’s you might expect which of the following lab abnormalities? EXAM QUESTION

A

Normal ACTH, high cortisol

44
Q

In a normal individual 1 mg of dexamathesone would result in which of the following? Exam question

A

ACTH and cortisol suppression after a night of sleep

45
Q

Which of the following electrolytes imbalances would you expect with Cushing’s? EXAM QUESTION

A

HYPERnatremia

HYPOkalemia

Endocrinology Week 2 (12 decks)

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