II. Indications

  1. Metabolic Alkalosis evaluation
    1. Differentiates Chloride Depletion Metabolic Alkalosis from non-chloride depletion

III. Interpretation: Normal

  1. Urine Chloride >20 mEq/L (>20 mmol/L)
  2. Urine Chloride: 110-250 mEq per 24 hours

IV. Causes: Decreased Urine Chloride <20 mEq/L (Chloride Depletion Metabolic Alkalosis)

  1. Gastrointestinal causes
    1. Vomiting
    2. Nasogastric suction
    3. Chloride-wasting Diarrhea
    4. Villous adenoma of colon
  2. Renal Causes
    1. Diuretic use
      1. Urine Chloride >10 meq/L and may vary considerably (including >20 mEq/L)
    2. Poorly reabsorbable anion
      1. Carbenicillin
      2. Penicillin
      3. Sulfate
      4. Phsophate
    3. Post-Hypercapnia
  3. Exogenous alkali
    1. Sodium Bicarbonate (Baking Soda)
    2. Sodium Citrate
    3. Lactate
    4. Gluconate
    5. Acetate
    6. Transfusion
    7. Antacid
  4. Other causes
    1. Cystic Fibrosis
    2. Achlorhydria
    3. Contraction alkalosis (Dehydration)

V. Causes: Urine Chloride >20 mEq/L (Non-Chloride Depletion Metabolic Alkalosis)

  1. Hypertensive Patient
    1. Adrenal Disease
      1. Primary Hyperaldosteronism
      2. Cushing's Syndrome (Pituitary, Adrenal or ectopic)
      3. Liddle Syndrome
    2. Exogenous steroids
      1. Excess Mineralocorticoid intake
      2. Excess Glucocorticoid intake
      3. Excessive licorice intake
      4. Carbenoxalone
      5. Glycyrrhizic acid
      6. Chewing Tobacco
  2. Normotensive Patient
    1. Bartter Syndrome or Gitelman Syndrome
    2. Hypokalemia
    3. Excessive alkali administration
    4. Milk-Alkali Syndrome
    5. Refeeding alkalosis
    6. Overcompensation for chronic Respiratory Acidosis (esp. chronic COPD with hypercapnia)
    7. Excessive Mechanical Ventilation (excess bicarbonate is typically slow to correct)

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