Adrenal disorders Flashcards
How do you determine the cause of cortisol excess in a patient presenting with cushing syndrome?
- Low dexamethasone suppression test: 1-2 mg dexamethasone given at night. Low cortisol should normally be found the next morning; if this is found, the sx aren’t due to an intrinsic cause. High cortisol suggests an intrinsic cause and requires further work-up (high dose dexamethasone suppression test
- Collect 24 hr cortisol
If normal, you don’t have cushing syndrome
If still high, perform a 48 hr high dose (8 mg) dexamethasone test:
-If this suppresses cortisol production, you have a PITUITARY adenoma
-If there is no suppresion, check ACTH level. If ACTH level is high, you have a nonadrenal ACTH secreting tumor. If ACTH is low, you have an adrenal tumor
What are common causes of Cushing syndrome?
-Cushing disease (aka pituitary adenoma), adrenal tumor, exogenous steroid administration, ACTH secreting tumor
What may be helpful in decreasing symptoms of Cushing syndrome due to paraneoplastic disease?
octreotide
What are complications of cushing syndrome?
cataracts, incr. risk of thromboembolic and cardiovascular disease, increased infection risk, AVASCULAR NECROSIS OF THE HIP, adrenal insufficiency after surgery
What is excess aldosterone production due to an adrenal tumor called?
Conn syndrome
How is primary hyperaldosteronism distinguished from secondary hyperaldosteronism?
Primary (due to adrenal tumor) has high ratio of serum aldo: plasma renin
Secondary (due to percieved hypovolemia in the kidney) has normal aldo:renin ratio
What are the 3 types of adrenal insufficiency:
- Addison’s disease/primary adrenal insufficiency (problem with the adrenal gland)
- Secondary insufficiency- problem with the pituitary
- Tertiary: problem with the hypothalamus and corticotropin releasing hormone (CRH)
How do you distinguish between Addison’s disease and 2/3ary adrenal insufficiency
- Addison’s pts more likely to be hyperpigmented
- Cortisol increases following administration of cosyntropin (an ACTH analogue) in secondary or tertiary diseaese, but doesn’t increase in addison’s disease
How is adrenal insufficiency treated?
- glucocorticoid replacement (hydrocortisone, dexamethasone, prednisone)
- mineralocorticoid replacement (usually only in addison’s disease)
- DHEA
- Hydration
What is an Addison’s crisis?
weakness, fever, mental status changes, vascular collapse due to stress and increased cortisol requirements
How is Addison’s crisis treated?
give IV glucose and hydrocortisone/vasopressors
What is the most common form of congenital adrenal hyperplasia? What is the back-up and what are the symptoms?
- 21 hydroxylase deficiency
- 17-alpha-hydroxyprogesterone in excess (it is the product before the enzyme)
- Patients present with excess androgens and not enough cortisol or aldosterone, leading to ambiguous genitalia in females, hypotension, salt wasting, and hyperkalemia
What is 17-alpha-hydroxylase deficiency? What is the “back-up” product and and what are the symptoms?
- Too much aldosterone
- Not enough sex hormones or cortisol
- leads to hypertension, low K, high Na, ambiguous genitalia in men, amenorrhea in women
- Not enough 17-alpha-hydroxyprednisone
What is 11-beta-hydroxylase deficiency?
- Too much deoxycortisone, too much androgen
- Not enough cortisol, not enough aldosterone
- Ambiguous genitalia and virilization in females, HTN due to too much deoxycortisone
How is pheo diagnosed?
increased 24 hr urine catecolamines and metanephrines; increased plasma-free metanephrines, icnreased 24 hr vanillylmandelic acid (though rarely performed)
