Adrenal Cortex (continued) Flashcards
What is the primary test for primary vs. secondary hypocortisolism?
ACTH stimulation test:
cortisol levels increase: normal
cortisol levels increase only slightly: hypocortisolism
Definitive test:
Just look at ACTH
Increased = primary hypocortisiolism (Addison’s );
inappropriately low = secondary hypocortisolism
Understand this chart.
Understand chart
Another name for primary hyperaldosteronism?
Conn’s Syndrome
What is Conn’s syndrome caused by?
a small unilateral adenoma on either side (most common);
bilateral adrenal hyperplasia (idiopathic hyperaldosteronism;
or adrenal carcinoma (rare)
What is an initial clue for presence of Conn’s syndrome?
detection of hypertension with hypokalema
What are some clinical features of primary hyperaldosteronism? (List 5)
- increased whole body sodium, fluid, and circulating blood volume
- infrequent hypernatremia
- increased peripheral vasconstriction and TPR
- BP (from borderline to severe HTN)
- edema (rare) (sodium escape, i.e a major increase in sodium and water retention is prevented by “sodium escape” but mechanism is unclear)
- models left ventricular hypertrophy
- potassium depletion and hypokalemia (causing weakness and fatigue)
- Increased hydrogen ion excretion and new bicarbonate create metabolic alkalosis
- Positive Chvostek or Trousseau’s sign (suggestive of alkalosis leading to low Ca2+)
- Normal cortisol level
- suppressed renin (major feature)
What is secondary hyperaldosteronism?
refers to a state in which there is an appropriate increase in aldosterone in response to activation of RAAS
What are the 2 types of secondary hyper-aldosteronism?
secondary hyper-aldosteronism with HTN
secondary hyper-aldosteronism with hypotension
Major cause of secondary hyperaldosteronism with HTN?
- primary over secretion of renin, secondary to a decrease in renal blood flow and/or pressure( most cases)
- renin secreting tumor (rare)
- renal arterial stenosis, narrowing via atherosclerosis, fibromuscular hyperplasia
What are some DDs to remember before diagnosing someone of secondary hyperaldosteronism with HTN?
Hypokalemia in a hypertensive patient not taking diuretics
hypo-secretion of renin with elevated aldosterone that fails to respond to a volume contraction: Conn’s syndrome
Hyper-secretion of renin with elevated aldosterone: renal vascular
What are the features of secondary hyper-aldosteronism with hypotension.
- sequestration of blood on the venous side of the systemic circulation (common cause)’
- results in dec. CO and thus dec. BF and pressure to the renal artery
- the following conditions produce:
CHF
Constriction of vena cava
hepatic cirrhosis
What are “inborn errors of metabolism”?
When there are single enzyme defects that lead to deficient cortisol secretion and the syndrome called CAH (congenital adrenal hyperplasia)
What is the most common of the congenital enzyme deficiencies?
21 β-hydroxylase deficiency
What is corticosterone?
a weak glucocorticoid
What are the consequences of 21 B-hydroxylase deficiency?
- mineralocorticoid deficiency in 75% cases
- neonates may present with salt-wasting crisis;= hyponatremia, hyperkalemia, and raised plasma renin
- elevated 17 hydroxyprogesterone
- increased androgens, leading to virilization of the female fetus and sexual ambiguity at birth
- males are phenotypically normal at birth but develop precocious pseudopuberty, growth acceleration, premature epiphyeseal plate closure and diminished final height
What is treatment for 21 B-hydroxylase defiency?
bringing glucocorticoid and mineralocorticoid back to normal range which also suppresses adrenal androgen secretion; in addition, hydrocortisone to act as feedback inhibition on pituitary
What are the consequences of 11 β- hydroxylase deficiency?
clinical features of increased androgens similar to the preceding form including virilization of female fetus
Principal difference with this form is the hypertension produced by 11-deoxycortiocsterone, along with hypokalemia and suprressed renin secretion
Treatment for 11 B- hydroxylase deficiency?
For all forms of CAH is gluocorticoids such as hydrocortisone and dexamethasone
What are the clinical features of 17 α- hydroxylase deficiency? (excluding testes and ovaries)
zona fasciculata, reticularis: decreased adrenal androgens, decreased cortisol, and increased ACTH.
increased 11-dexoycorticosterone leading to HTN
reduced circulating angiotensin II reduces stimulation os zona glomerulosa and aldosterone secretion
Be able to make a chart on the effects of 21 B-OH, 11 B OH, and 17 a-OH on glucocorticoids, ACTH, BP, Mineralocorticoid: Aldosterone Deoxycorticosterone levels , Androgen, Estrogen?
Reproduce chart.
