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Table 1-3

Causes of Hypokalemia

  • Decreased intake
    • Starvation
    • Clay ingestion
  • Redistribution into cells
    • Acid-base
      1. Metabolic alkalosis
    • 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
    • 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
    • Other
      1. Pseudohypokalemia
      2. Hypothermia
      3. Familial hypokalemic periodic paralysis
      4. Barium toxicity: systemic inhibition of “leak” K+ channels
    • Increased loss
      • Nonrenal
        1. Gastrointestinal loss (diarrhea)
        2. Integumentary loss (sweat)
      • Renal
        1. Increased distal flow and distal Na+ delivery: diuretics, osmotic diuresis, salt-wasting nephropathies
        2. Increased secretion of potassium
          • 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
          • 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)
          • 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.