Hormone Disturbances Causing Hypokalemia

Introduction to Hormone Disturbances

The primary hormone disturbances causing hypokalemia are primary aldosteronism, Cushing's syndrome, congenital adrenal hyperplasia, and other mineralocorticoid excess syndromes 1, 2, 3

Primary aldosteronism is the most frequent endocrine cause of hypokalemia with hypertension, occurring in 28.1% of all hypertensive patients with hypokalemia and up to 20% of those with resistant hypertension 4
Autonomous aldosterone production leads to sodium retention, potassium excretion, and suppressed plasma renin activity 4
Approximately 50% of primary aldosteronism is due to unilateral aldosterone-producing adenoma and 50% due to bilateral adrenal hyperplasia 4
The aldosterone-to-renin ratio (ARR) ≥30 is diagnostic when plasma aldosterone is ≥10 ng/dL 4, 5
Clinical presentation includes hypertension, often resistant, with spontaneous or diuretic-induced hypokalemia, muscle weakness, and cardiac arrhythmias from severe hypokalemia 1, 2, 3

Hypercortisolism causes hypokalemia through mineralocorticoid effects of excess cortisol 6, 1, 2, 3
Clinical features include central obesity, moon facies, dorsal and supraclavicular fat pads, wide violaceous striae, hirsutism, proximal muscle weakness, depression, hyperglycemia, and hypertension 1, 2, 3, 6
Diagnostic approach includes overnight 1-mg dexamethasone suppression test for screening and 24-hour urinary free cortisol excretion or midnight salivary cortisol for confirmation 1, 2, 3

Two specific enzyme deficiencies, 11-beta-hydroxylase and 17-alpha-hydroxylase, cause hypertension with hypokalemia 1, 2, 3
11-beta-hydroxylase deficiency presents with virilization, hypertension, and hypokalemia, while 17-alpha-hydroxylase deficiency presents with incomplete masculinization in males and primary amenorrhea in females 1, 2, 3
Diagnostic pattern includes hypertension and hypokalemia with low or normal aldosterone and renin levels 1, 2, 3

Rare causes include apparent mineralocorticoid excess, primary glucocorticoid resistance, and exogenous mineralocorticoid exposure 1, 2, 3
Clinical pattern includes early-onset or resistant hypertension with hypokalemia and low aldosterone and renin levels 1, 2, 3

Renovascular hypertension causes elevated renin, leading to secondary aldosterone elevation and hypokalemia 4
Distinguishing feature is that both aldosterone and renin are elevated, unlike primary aldosteronism where renin is suppressed 4, 5

Thyroid hormone excess can cause hypokalemia through transcellular potassium shifts 1, 2, 3, 5
Clinical features include warm, moist skin, heat intolerance, nervousness, tremulousness, weight loss, diarrhea, proximal muscle weakness, lid lag, and fine tremor 1, 2, 3
Screen with thyroid-stimulating hormone and free thyroxine 1, 2, 3, 5

When evaluating hypokalemia with hypertension, measure plasma aldosterone and renin to calculate ARR 4
If ARR ≥30 with aldosterone ≥10 ng/dL, consider primary aldosteronism; if both aldosterone and renin elevated, consider renovascular hypertension; if aldosterone and renin both low, consider Cushing's syndrome, congenital adrenal hyperplasia, or other mineralocorticoid excess syndromes 1, 2, 3, 4, 5
Check thyroid function in all cases, as hyperthyroidism is a common overlooked cause 5

The American College of Cardiology notes that 11β-hydroxylase deficiency causes accumulation of 11-deoxycorticosterone (DOC) and 11-deoxycortisol, leading to hypertension and hypokalemia in affected patients 7
Clinical presentation of 11β-hydroxylase deficiency includes virilization, hypertension, and hypokalemia, with laboratory confirmation revealing elevated deoxycorticosterone (DOC), 11-deoxycortisol, and androgens 7
17α-hydroxylase deficiency blocks glucocorticoid and sex steroid synthesis, shunting precursors toward mineralocorticoid pathways, and presents with incomplete masculinization in males and primary amenorrhea in females, along with severe hypertension and hypokalemia 7

The Endocrine Society guidelines suggest that osilodrostat inhibits 11β-hydroxylase and aldosterone synthase, causing accumulation of 11-deoxycortisol and 11-deoxycorticosterone, which activate mineralocorticoid receptors and lead to hypokalemia, edema, and hypertension in 42% of treated patients 8
Metyrapone blocks 11β-hydroxylase, causing similar accumulation of androgenic and mineralocorticoid precursors, resulting in hirsutism, hypertension, and hypokalemia from precursor accumulation 8, 9
The American Heart Association recommends that hypokalemia should be corrected prior to initiating osilodrostat, and patients require ongoing monitoring for worsening hypertension and edema 8

The European Society of Endocrinology suggests measuring plasma aldosterone and renin to calculate the aldosterone-to-renin ratio (ARR) when evaluating a patient with hypertension and hypokalemia 7
If both aldosterone and renin are low or suppressed, screen for Cushing's syndrome and consider congenital adrenal hyperplasia with measurement of specific precursors, such as 11-deoxycortisol, DOC, and androgens for 11β-hydroxylase deficiency 7

The American College of Endocrinology recommends glucocorticoid replacement therapy for congenital adrenal hyperplasia, which suppresses ACTH and reduces precursor production, resolving hypertension and hypokalemia 7
For osilodrostat- or metyrapone-induced precursor excess, add potassium supplementation and consider mineralocorticoid antagonists if hypokalemia persists despite supplementation 8