CCL 1 Pre-Learn

Question 1

signs of secondary hypertension

Answer 1

*severe or refractory HTN, requiring 3+ medications
*acute rise in BP over a previously stable control
*proven age of onset before puberty
*age < 30 years in non-obese pt, neg family history

Question 2

triad of secondary hypertension

Answer 2

1. hypertension
2. hypokalemia
3. metabolic alkalosis

Question 3

effects of increased aldosterone → increased blood pressure

Answer 3

*effects of aldosterone:
-increases endothelin secretion
-increases sympathetic tone → increased activation of RAAS
-decreased NO-mediated vasodilation
-increased vasoconstriction
-renal NaCl retention

*ALL of these factors contribute to increasing BP

Question 4

mechanism of hypokalemia in secondary hypertension

Answer 4

increased aldosterone leads to:
*increased Na+/K+ ATPase activity to create gradient for Na
*increased number of ENaC transporters
*increased number of ROMK channels

result: increased aldosterone → increased potassium excretion / potassium wasting in urine → HYPOKALEMIA

Question 5

mechanism of metabolic alkalosis in secondary hypertension

Answer 5

increased aldosterone leads to:
*stimulates H+/K+ ATPase
*stimulates H+ ATPase

result: increased aldosterone → excretion of H+ in the urine → METABOLIC ALKALOSIS

Question 6

renal artery stenosis - clinical presentation

Answer 6

*severe refractory HTN
*+/- hypokalemia
*renal failure
*harsh abdominal bruit
*flash pulmonary edema

Question 7

renal artery stenosis - pathogenesis

Answer 7

*kidney perceives decreased blood flow → increased renin, increased Ang II, increased aldosterone → increased blood pressure

Question 8

renal artery stenosis - diagnosis

Answer 8

*renal artery duplex
*CT angiogram
*MR angiogram

Question 9

renal artery stenosis - treatment

Answer 9

1. medical anti-hypertensives:
   -note: caution with ACEi, especially in BILATERAL RAS
2. intervention: angioplasty, stenting, surgical bypass
   -more useful in fibromuscular dysplasia
   -no convincing evidence to support use in atherosclerotic RAS

Question 10

renin producing tumor - overview

Answer 10

*typically seen in young patients
*tumor produces renin → severe hypertension with hypokalemia
*most cases due to benign JG cell tumors
*dx: dedicated renal CT
*tx: surgical removal

Question 11

primary aldosteronism - overview

Answer 11

*either due to:
1. aldosterone-producing tumor
OR
2. bilateral adrenal hyperplasia

*results in increased aldosterone levels with decreased renin leveles

Question 12

primary aldosteronism - diagnosis

Answer 12

*plasma aldosterone-renin ratio (ARR):
-normal ~10
-25 to 50: possible
-50+: likely

*renin measured by plasma renin activity
*can confirm with a plasma aldosterone or 24 hour urine while on a high salt diet
*imaging to find the tumor (adrenal CT or MRI)

Question 13

primary aldosteronism - treatment

Answer 13

*if adrenal adenoma is seen, ideally must determine if it is functional with adrenal vein sampling
*if good surgical candidate, laparoscopic adrenalectomy
*persistent post op HTN may be due to microvascular renal disease

Question 14

bilateral adrenal cortical hyperplasia - overview

Answer 14

*2 associated enzyme deficiencies:

1. 11-beta hydroxylase deficiency:
   → buildup of deoxycorticosterone and 11-deoxycortisol (weak mineralocorticoids)
   → buildup of androgens
2. 17-alpha hydroxylase deficiency:
   → buildup of deoxycorticosterone, corticosterone, aldosterone
   → sexual ambiguity

*results in increased aldosterone with decreased renin levels

Question 15

Cushing’s Syndrome - etiology

Answer 15

*overall: excess cortisol
*can be related to:
1. pituitary adenoma: ACTH production → cortisol
2. ectopic ACTH production → stimulates cortisol excretion
3. adrenal adenoma/carcinoma → produces cortisol, low ACTH

Question 16

Cushing’s Syndrome - physical exam findings

Answer 16

*ACTH → increased pigmentation
*excess cortisol:
-BUFFALO HUMP
-MOON FACIES
-upper body obesity
-other findings

Question 17

Cushing’s Syndrome - diagnosis

Answer 17

*screen with 24h urine cortisol
*low dose dexamethasone suppression test (should decrease secretion of cortisol in normal patients)

Question 18

Cushing’s Syndrome - treatment

Answer 18

*surgical resection of tumor if possible

Question 19

Liddle’s Syndrome - pathogenesis

Answer 19

*gain of function mutation of ENaC channels → channel remains active/open in the cell for prolonged period → HTN, hypokalemia, metabolic alkalosis
*decreased aldosterone and decreased renin, due to feedback mechanism

Question 20

Liddle’s Syndrome - treatment

Answer 20

*sodium restriction and K+ supplementation
*amiloride or triamterene (K+ sparing diuretics that inhibit ENaC)

Question 21

Syndrome of Apparent Mineralocorticoid Excess (SAME) - overview

Answer 21

*appears like there is a lot of aldosterone
*sx: HTN, hypokalemia, metabolic alkalosis
*decreased aldosterone and decreased renin, due to feedback

Question 22

Syndrome of Apparent Mineralocorticoid Excess (SAME) - pathogenesis

Answer 22

*mineralocorticoid receptor binds both aldosterone and cortisol (weakly)
*inhibition of 11-beta HSD → cortisol cannot be broken down
*cortisol is able to constitutively stimulate MR → renal Na reabsorption and K+ secretion

*note: genetic or acquired (licorice with derivatives of glycyrrhizic acid)