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Table 1-3

Causes of Hypokalemia

I. Decreased intake

  1. Starvation
  2. Clay ingestion

II. Redistribution into cells

  1. Acid-base
    1. Metabolic alkalosis
  2. Hormonal
    1. Insulin
    2. Increased β2-adrenergic sympathetic activity: post-myocardial infarction, head injury, theophylline
    3. β2-Adrenergic agonists: bronchodilators, tocolytics
    4. α-Adrenergic antagonists
    5. Thyrotoxic periodic paralysis
    6. Downstream stimulation of Na+/K+-ATPase: theophylline, caffeine
  3. Anabolic state
    1. Vitamin B12 or folic acid administration (red blood cell production)
    2. Granulocyte-macrophage colony-stimulating factor (white blood cell production)
    3. Total parenteral nutrition
  4. Other
    1. Pseudohypokalemia
    2. Hypothermia
    3. Familial hypokalemic periodic paralysis
    4. Barium toxicity: systemic inhibition of “leak” K+ channels

III. Increased loss

  1. Nonrenal
    1. Gastrointestinal loss (diarrhea)
    2. Integumentary loss (sweat)
  2. Renal
    1. Increased distal flow and distal Na+ delivery: diuretics, osmotic diuresis, salt-wasting nephropathies
    2. Increased secretion of potassium
      1. Mineralocorticoid excess: primary hyperaldosteronism (APAs), PAH or UAH, IHA due to bilateral adrenal hyperplasia and adrenal carcinoma, familial hyperaldosteronism (FH-I, FH-II, congenital adrenal hyperplasias), secondary hyperaldosteronism (malignant hypertension, renin-secreting tumors, renal artery stenosis, hypovolemia), Cushing's syndrome, Bartter's syndrome, Gitelman's syndrome
      2. Apparent mineralocorticoid excess: genetic deficiency of 11β-dehydrogenase-2 (syndrome of apparent mineralocorticoid excess), inhibition of 11β-dehydrogenase-2 (glycyrrhetinic/glycyrrhizinic acid and/or carbenoxolone; licorice, food products, drugs), Liddle's syndrome (genetic activation of ENaC)
      3. Distal delivery of nonreabsorbed anions: vomiting, nasogastric suction, proximal renal tubular acidosis, diabetic ketoacidosis, glue sniffing (toluene abuse), penicillin derivatives (penicillin, nafcillin, dicloxacillin, ticarcillin, oxacillin, and carbenicillin)
    3. Magnesium deficiency, amphotericin B, Liddle's syndrome

Abbreviations: APA, aldosterone-producing adenoma; ENaC, epithelial Na+ channels; IHA, idiopathic hyperaldosteronism; PAH, primary adrenal hyperplasia; UAH, unilateral adrenal hyperplasia.