Lecture 13: Adrenal Gland Flashcards
What are mineralocorticoids, glucocorticoids, and androgen estrogens synthesized from?
cholesterol
What stimulates the release of cortisol from the adrenal cortex?
stress acting on the hypothalamus which eventually causes the pituitary gland to release ACTH to the adrenal cortex
How is a dexamethasone suppression test performed?
low dose test- give .5mg dexamethasone every 6 hours for 8 doses
What is the most useful test for adrenal insufficiency?
ACTH stimulation test
What is a normal response for an ACTH stimulation test?
a cortisol level > 20 mg/dl
How does an ACTH stimulation test work?
250 mg of Cortrosyn or Cosyntropin are given and serum cortisol is measured 60 minutes later
What is an ACTH stimulation test result that is consistent with Addison’s disease?
pre ACTH cortisol is low and post ACTH cortisol is low
What is CRH stimulation test used to differentiate?
primary and secondary adrenal insufficiency
What are the CRH stimulation test results in primary adrenal insufficiency?
elevated ACTH but no cortisol production
What are the CRH stimulation test results in secondary adrenal insufficiency?
low ACTH and Low cortisol
What is the most important test to diagnose hyper and hypoaldosteronism?
aldosterone concentration
how can aldosterone concentration be measured?
serum or urine
What other test should be used besides aldosterone concentration when screening for primary aldosteronism?
renin activity level (PRA)
What factors can affect aldosterone concentration?
potassium level, sodium level, inactivity, drugs
What does plasma renin activity measure?
ability to convert angiotensinogen to angiotensin I
What are elevated Plasma Renin Activity results seen in?
hyperaldosteronism
What are signs ad symptoms of Cushing’s Syndrome?
rapid weight gain, moodiness, irritability, depression, muscle weakness, osteoporosis, diabetes mellitus, hypertension, immunosuppression, hair pattern changes, amenorrhea, infertility, buffalo hump, abdominal striae, adrenal tumor or hyperplasia, skin ulcers, poor wound healing
What happens to the levels of ACTH in cushing’s syndrome
excess production of ACTH by pituitary
What are the different types of cushing’s syndromes?
pituitary adenoma, ectopic ACTH, adrenal tumors, familial cushing’s, drug related
What is step one for diagnosing cushing’s syndrome?
look for high cortisol level by taking 24 hour urine cortisol and salivary cortisol
What is step two in diagnosing cushing’s syndrome?
finding the level of the problem; dexamethasone suppression test; CRH stimulation test to distinguish between pituitary and hypothalamus
What is step 3 in diagnosing cushing’s syndrome?
looking for treatable causes by CT, MRI for tumors
When should you check ACTH level for adrenal insufficiency?
when cortisol level is the highest (late morning)
When is the best time to measure ACTH for cushing’s syndrome?
when cortisol is low (midnight to 2am)
What is the most important test to diagnose hyper and hypoaldosteronism?
aldosterone concentration
What are the causes for high cortisol?
taking steroids, diseases that cause excess cortisol, ACTH or CRH, tumors
What are the cushing’s syndromes?
pituitary adenomas, ectopic ACTH, adrenal tumors, familial, familial cushing’s, drug related
What are some clinical manifestations of ACTH Deficiency?
nausea, vomiting, weakness, fatigue, fever, hypotension
What are some causes of a destruction of the adrenal cortex?
autoimmune disorders, tuberculosis, chronic infections
What are some secondary causes for a lack of ACTH?
drugs, tumors and infections of pituitary gland
What are two major things that are affected with a primary destruction of the adrenal cortex?
low cortisol and low aldosterone
What differentiates Addison’s disease?
aldosterone
how does hypertension affect blood potassium?
it decreases blood potassium
What happens when a person has low blood potassium?
tiredness, muscle weakness, polyuria
What are some common causes of secondary hyperaldosteronism?
CHF, nephrotic syndrome, Cirrhosis
What are the male symptoms of congenital adrenal hypoplasia?
Enlarged penis Failure to regain birth weight Weight loss Dehydration Vomiting Precocious puberty Rapid growth during childhood, but shorter than average final height.
What are the female symptoms of congenital adrenal hypoplasia?
Ambiguous genitalia Failure to regain birth weight Weight loss Dehydration Vomiting Precocious puberty Rapid growth during childhood, but shorter than average final height. Infertility Irregular or absent menstruation Masculine characteristics
