Adrenal Disorders

Question 1

What are the primary functions of the glucocorticoids?

Answer 1

protects against stress and affects protein and carbohydrate metabolism. Think cortisol.

Question 2

What are the primary functions of the mineralcorticoids?

Answer 2

regulates the retention and excretion of fluids and electrolytes (especially Na and K) by the kidneys.
Think aldosterone.

Question 3

What are the primary functions of the adrenal androgens?

Answer 3

Pubertal growth of body hair. Exert little effect on sexual function. Think DHEA (dehydroepiandrosterone)

Question 4

What are chromaffin cells?

Answer 4

main source of catecholamines in the adrenal medulla

Question 5

What effect can cortisol have on the adrenal medulla?

Answer 5

Cortisol produced in the adrenal cortex that reaches the medulla in high levels causes up regulation in the production of epinephrine

Question 6

What are the effects of epi and norepi on the cardiovascular system?

Answer 6

Strengthens the contractility of the myocardium. (Beta1 action, inotropic action). Increases rate of contraction (Beta1 action, chronotropic action). Constricts arterioles in the skin (Alpha1 action). Dilates vessels to liver and skeletal muscle (Beta2 action)

Question 7

What are the effects of epi and norepi on the respiratory system?

Answer 7

bronchodilation by acting directly on bronchial smooth muscle (Beta2 action). relieves all known allergic- or histamine-induced bronchoconstriction in anaphylactic shock

Question 8

What is a pheochromocytoma?

Answer 8

tumor derived from neural crest cells of the sympathetic nervous system that causes episodic symptoms (palpitations, sweating, HA, fainting, HTN) because it releases catecholamines

Question 9

What is the 90% rule of pheochromocytomas?

Answer 9

90% of the time they arise from the adrenal medulla, 90% are unilateral, 90% aren’t malignant, 90% occur in adults

Question 10

How is a pheochromocytoma diagnosed?

Answer 10

H/P. elevated urinary excretion of catecholamines or their metabolites (metanephrines and vanillylmandelic acid) DURING a period of HTN. CT of abdomen or MRI

Question 11

What is the function of aldosterone?

Answer 11

Increases sodium (Na) and water reabsorption by the kidneys AND increases the secretion of potassium (K), thereby indirectly regulating blood volume and blood pressure

Question 12

Describe the renin-angiotensin-aldosterone system of the kidneys.

Answer 12

Fall in blood pressure –> juxtaglomerular cells secrete renin. Renin converts angiotensinogen to angiotensin I which is converted to angiotensin II in the lungs. Angiotensin II constricts blood vessels and stimulates the adrenal cortex to secrete aldosterone reducing urine output and increasing BP by increasing blood volume

Question 13

What are the specific immunologic and antiinflammatory effects of cortisol?

Answer 13

Suppresses immune response by reducing humoral and cell-mediated immunity. Exogenous steroids block inflammation by decreasing capillary permeability and stabilizing lysosomal membranes so inflammatory mediators are not released. blocks release of arachidonic acid, the precursor of prostaglandins and leukotrienes

Question 14

What are adverse effects of excess glucocorticoids?

Answer 14

hyperglycemia, suppresses the immune system, decreased bone density, CNS psychosis, HTN, stimulate gastric acid and pepsin production

Question 15

What is Cushing’s syndrome?

Answer 15

prolonged exposure to excessive glucocorticoid hormones that’s either endogenous (ACTH dependent-Cushings disease or ACTH independent-adrenal adenoma/carcinoma) or exogenous (excessive steroid administration)

Question 16

What is Cushing’s disease?

Answer 16

excessive production of ACTH from a pituitary tumor or ectopic sources of ACTH from small cell lung cancer

Question 17

What is the most direct and reliable index of cortisol secretion?

Answer 17

24-hour urinary cortisol excretion. Should be performed in a nonstressful outpatient setting. Urine creatinine should be measured as well to confirm an adequate 24-hour collection

Question 18

What diagnostic tests/tools might be useful if a patient is found to have elevated urinary cortisol?

Answer 18

Plasma ACTH (recommended measurement between midnight and 2AM). Abdominal CT scan (looking for adrenal mass). MRI of the sella for pituitary tumor

Question 19

What is the dexamethasone suppression test?

Answer 19

1mg dexamethasone (a steroid) given orally in the evening. Serum cortisol determination at about 8am the next AM. HPA axis should be suppressed with normal physiology

Question 20

What is primary adrenal insufficiency?

Answer 20

Addison’s disease: Most common cause of adrenal insufficiency. Results from destruction or dysfunction of the adrenal cortex. Glucocorticoid and mineralocorticoid secretion is reduced. May be fatal if untreated

Question 21

What is secondary adrenal insufficiency?

Answer 21

Results from inadequate stimulation of adrenal cortex by ACTH. Usually occurs after discontinuation of exogenous steroids that cause prolonged suppression of the HPA (Hypothalamic-pituitary-adrenal) axis

Question 22

What is the clinical presentation of adrenal insufficiency?

Answer 22

hypotension, weight loss, fatigue, vomiting, diarrhea, anorexia, muscle/jt pain, abdominal pain, postural dizziness

Question 23

Why is hyperpigmentation a common presentation with Addison’s disease?

Answer 23

Decreased levels of cortisol means less inhibition of HPA axis. The leads to increased proopiomelanocortin (POMC) synthesis. POMC contains melanocyte-stimulating hormone (MSH) fragments. When POMC levels are increased, so are levels of MSH, leading to pigmentation of the skin

Question 24

Why is salt craving a common presentation with Addison’s disease?

Answer 24

low secretion of aldosterone leads to hyponatremia and salt craving

Question 25

What is the ACTH stimulation test?

Answer 25

Plasma cortisol measured. IV administration of 250 ug of ACTH. In 30-60 minutes plasma cortisol measured again.

Question 26

How do you distinguish between primary or secondary adrenal insufficiency using lab tests?

Answer 26

plasma ACTH is increased in primary adrenal insufficiency and decreased in secondary adrenal insufficiency

Question 27

How is Addison’s disease treated?

Answer 27

Lifelong replacement of glucocorticoids AND mineralocorticoids. Doses should mimic diurnal surges with larger dose administered in the AM and smaller dose given around 4pm. Main adverse effect is overtreating. Mineralocorticoids can be monitored by measuring plasma renin (kept btw 1-3)

Question 28

What is treatment of an acute adrenal insufficiency (Addisonian Crisis)?

Answer 28

administration of IV hydrocortisone is lifesaving

Question 29

What are some common prescription glucocorticoids?

Answer 29

hydrocortisone, prednisone, methylprednisolone, dexamethasone

Question 30

What is the commonly prescribe mineralocorticoid?

Answer 30

fludrocortisone

Question 31

What are therapeutic uses of glucocorticoids?

Answer 31

Relief of inflammatory symptoms, replacement for adrenal insufficiency, and acceleration of lung maturation

Question 32

What are the therapeutic uses of fludrocortisone?

Answer 32

Has both glucocorticoid and mineralocorticoid activity but glucocorticoid amounts are too low to elicit anti-inflammatory effects. Used for adrenal insufficiency