disorders of the adrenal gland Flashcards

1
Q

where is the problem located in the hypothalamic-pituitary axis for: primary, secondary, and tertiary disorder

A

primary = target organ

secondary = pituitary

tertiary = hypothalamus
*more organs involved

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2
Q

what is the predominant feedback loop w/in the endocrine system?

A

Negative

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3
Q

example of a positive feedback loop?

A

oxytocin

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4
Q

what types of hormones are produced in the 4 zones of the adrenal gland?

A

outer = Mineralocorticoids (Aldosterone)

middle = Glucocorticoids (Cortisol)

inner = Adrenal Androgens (DHEA)

medulla = Catecholamines (epi and NE)

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5
Q

aldosterone causes increased reaborptionn of ____ and increased excretion of _____.

A

Na and water

K+ and H+

aldosterone controls fluid volume**

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6
Q

describe cortisol secretion

A

it is pulsatile (stress), diurnal (circadian regulation), and under control of ACTH

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7
Q

long term high dose glucocorticoid therapy can cause…?

A

adrenal atropohy

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8
Q

primary overproduction of cortisol by adrenal glands inhibits _____.

A

ACTH secretion

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9
Q

what is the role of glucocorticoids (cortisol) in the body?

A
Protects against hypoglycemia
Decrease insulin sensitivity
Anti-inflammatory
Suppression of immune responses
Maintain vascular responsiveness to NE/Epi
Inhibits bone formation
Promotes increases in GFR
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10
Q

what effect can “weak” androgens have in males/females?

A

males –> limited physiological significance

females –> major source of androgens (pubic and axillary hair during early development), masculinization

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11
Q

How can you measure catecholamine levels?

A

urine test bc metabolites are excreted in the urine

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12
Q

what are some physiologic effects of catecholamines?

A
Increased rate and force of contraction of the heart muscle
Constriction of blood vessels
Stimulation of lipolysis in fat cells
Increased metabolic rate
Dilation of the pupils
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13
Q

effects of short-term stress response in the body

A

increased HR and BP, liver converts glycogen to glucose > releases glucose to blood, incr. metabolic rate

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14
Q

effects of long-term stress response in the body

A

retention of Na/H2O by kidneys, incr. blood volume and BP, proteins and fats converted to glucose or broken down, increased blood sugar, suppression of immune system

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15
Q

What type of test would assess for hypofunctioning? hyperfunctioning?

A

hypo = stimulation test

hyper = suppression test

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16
Q

what are adrenal lab tests?

A
Serum total cortisol
24-hour urinary free cortisol
Plasma ACTH
ACTH stimulation
Dexamethasone suppression
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17
Q

when should you obtain a serum cortisol level?

A

btwn 8-9am

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18
Q

what lab values would indicate adrenal insufficiency?

A

serum total cortisol:
< 3 = very likely adrenal insufficiency

btwn 3-10 = inconclusive

> 10 = unlikely adrenal insufficiency

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19
Q

what is the ideal situation for using a 24-hr urinary free cortisol test?

A

suspected hypercortisolism

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20
Q

where is ACTH produced?

A

pituitary

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21
Q

what time of day should you measure plasma ACTH?

A

in the AM

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22
Q

when would you order an ACTH stimulation test?

A

to differentiate source of adrenal insufficiency (cortisol deficiency)

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23
Q

ACTH stimulation test: if cortisol level doubles where is the problem?

if it is a subnormal response where is the problem?

A

no problem. adrenal gland is functioning!

adrenal insufficiency

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24
Q

what is the dexamethasone suppression test confirm?

A

Confirm abnormal excess production

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25
Dexamethasone Suppression Test: what result would indicate excess cortisol production
if cortisol level does not change | if suppressed = normal fx
26
Cushing's syndrome?
Collection of signs and symptoms due to prolonged exposure to elevated cortisol MC overal is excess d/t exogenous use
27
Cushing's syndrome d/t endogenous reasons?
MC = Pituitary adenoma adrenal hyperplasia Adrenocortical tumor Neuroendocrine tumor Ectopic production
28
clinical manifestations of cushing's syndrome?
HTN, central obesity (moon face), insulin resistance, purple striae, androgen excess (hirsutism), osteoporosis
29
what 3 signs would increase your suspicion for cushing's?
characteristic body changes HTN glucose intolerance
30
what tests would you order to dx cushing's? what are results consistent w/ cushing's?
24-hour urinary free cortisol levels = Elevated Midnight salivary cortisol level = Elevated on 2 separate nights Dexamethasone suppression test = No change in cortisol levels
31
Cortisol and ACTH levels for Adrenal hyperplasia or tumor?
cortisol = High ACTH = low *target organ problem! ACTH independent
32
Cortisol and ACTH levels for ACTH producing tumor – pituitary or ectopic?
cortisol = high ACTH = high *ACTH dependent
33
Management of Cushing's syndrome?
excluded exogenous cortisol use? pituitary tumor --> consider MRI ectopic ACTH secreting tumor --> consider CXR and pelvic U/S adrenal tumor --> palp mass? CT abd
34
Tx for exogenous corticosteroids?
taper to lowest therapeutic dose
35
Tx for pituitary adenoma in cushing's syndrome
transsphenoidal resection
36
tx for adrenal hyperplasia in cushing's syndrome
medical management
37
tx for adrenal tumor in cushing's syndrome
adrenalectomy
38
tx for Ectopic ACTH syndrome in cushing's syndrome
targeted at source of ectopic production
39
What medications can you use to tx cushing's?
adrenolytic agents- mitotane | adrenal enzyme inhibitors- Ketoconazole, metyrapone
40
what is adrenal insufficiency? | primary, secondary, tertiary
primary -> glucorticoid defiencies secondary -> insufficient ACTH secretion (long term corticoco's) tertiary -> insufficient CRH secretion
41
causes of primary adrenal insufficiency?
MC in US d/t autoimmune cortical destruction (addison's dz), TB (worldwide), congenital deficiencies, infx, surg (s/p adrenalectomy)
42
clinical manifestations of adrenal insufficiency
Insidious onset w/ nonspecific symptoms (weakness, fatigue, anorexia, wt. loss), GI sxs (V/D, abd pain), hypotension, hypoglycemia, salt cravings, **hyperpigmentation - classic severe --> extremely low levels of cortisol
43
diagnostic studies assoc. w/adrenal insufficiency
CMP (hyperkalemia, hypercalcemia, hyponatremia) eosinophilia andi-adrenal antibodies AM plasma cortisol (abn low) plasma ACTH level ACTH stimulation test (cortisol does NOT incr)
44
when do you order a radiographic eval of the adrenals for insufficiency?
if the lab workup reveals autoimmune adrenalitis CT -> infx or malignancy
45
when should you order an MRI of the pituitary for adrenal insufficiency?
if secondary adrenal insufficiency points toward hypothalamic or pituitary source
46
Tx for primary adrenal insufficiency
requires both glucocorticoid (hydrocortisone) & mineralocorticoid (fludrocortisone) replacement
47
Tx for secondary and tertiary Adrenal insuffiency
only glucocorticoid replacement is necessary
48
what do you need to do if pt is on meds for adrenal insufficiency and they are going through a period of increased stress?
increase the steroids during the period of stress
49
Tx for adrenal crisis?
``` IV steroids Correct electrolyte abnormalities 50% dextrose to correct hypoglycemia Initiate volume resuscitation Search for underlying cause ```
50
Primary hyperaldosteronism
aka Conn's syndrome d/t | adrenocortical adenoma or cortical hyperplasia
51
presentation of primary hyperaldosteronism
``` Hypertension Hypokalemia Muscular weakness Paresthesias Headache Polyuria & polydipsia ```
52
diagnostic workup for primary hyperaldosteronism
Elevated plasma and urine aldosterone Low plasma renin levels Ct scan of adrenals to evaluate for adrenal adenoma
53
management for primary hyperaldosteronism
Surgical removal of adenoma Medical = spironolactone and antihypertensive agents
54
what is Pheochromocytoma
Rare tumor that arises from chromaffin cells that secretes catecholamines 80% to 90% located in adrenal medulla 10% are malignant
55
clinical manifestations for pheochromocytoma
``` Paroxysmal Palpitations (tachycardia), Headache and Episodic sweating Paroxysmal or sustained hypertension ``` less common: pallor, N, tremor, fatigue, anxiety, hypertensive retinopathy
56
describe a Pheochromocytoma "attack"
Usu. last 30-40 minutes May be precipitated by displacement of abdominal contents (ie lifting, bending, deep palpation)
57
when to suspect a pheo?
Classic paroxysmal “attacks,” refractory HTN or onset <20 y/o, idiopathic dilated cardiomyopathy, abd mass, family hx, incidentally discovered adrenal mass
58
what is the 1st line screening for dx of pheochromocytoma?
metanephrine (catecholamine metabolite) 24hr urine screen
59
what other tests can you order to dx pheo?
Clonidine suppression test MRI of abd/pelvis to locate tumors MIBG scintigraphy
60
Tx of pheochromocytoma
surgical resection prior to surg - alpha adrenergic blocker until BP and sxs controlled - BB (propranalol) for tachy
61
Adrenal Incidentaloma
Mass lesion greater than 1 cm discovered incidentally by radiologic examination higher prevalence in obese, HTN, and DM pt's
62
workup for adrenal incidentaloma
Everyone gets plasma cortisol, serum ACTH, serum DHEA, plasma aldosterone s/s of cushing's --> yes = 24 hr urinary free cortisol no = 1-mg overnight dexamethasone suppression test susp. for pheo? 24-hr urine metanephrines, catecholamines
63
when is FNA/bx indicated for adrenal incidentaloma?
Do it --> known primary malignancy elsewhere Do NOT --> Biochemical evidence of pheo or known widespread metastatic disease
64
management of adrenal incidentaloma
documented pheo or carcinoma --> prompt surg. pharmacologic to tx underlying benign appearing on imaging: >2cm --> consider resection <2cm --> repeat imaging 6mo's repeat Dexamethasone suppr. test annually x4yrs