Metabolic Alkalosis

1. See Also
   1. Arterial Blood Gas
   2. ABG Interpretation
2. Types
   1. Chloride responsive Metabolic Alkalosis
      1. Loss of body acids (e.g. Vomiting, nasogastric suction)
      2. Extracellular fluid contraction
      3. Saline responsive
   2. Chloride-resistant Metabolic Alkalosis
      1. Increased body buffers
         1. Bicarbonate administration
         2. Renal reabsorption due to excess Mineralocorticoid
      2. Associated with Hypokalemia
      3. Saline unresponsive
3. Causes: Low Urine Chloride <10 meq/L
   1. Gastrointestinal causes
      1. Vomiting
      2. Nasogastric suction
      3. Chloride-wasting Diarrhea
      4. Villous adenoma of colon
   2. Renal Causes
      1. Diuretic use (Urine Chloride >10 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. Cystic Fibrosis
   5. Achlorhydria
   6. Contraction alkalosis
4. Causes: Normal or High Urine Chloride >20 meq/L
   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
5. Labs
   1. Arterial Blood Gas
      1. Arterial pH increased
      2. Serum bicarbonate increased
      3. PaCO2 increased (due to compensatory hypoventilation)
         1. PaCO2 = 0.7 x HCO3 + 20 (+/- 1.5)
         2. PaCO2 rises 6 mmHg per 10 meq/L bicarbonate rise
            1. PaCO2 rise is not uniform and roughly increases 1 mmHg for each 1 meq/L Bicarbonate
      4. Excess Anion Gap >30 mEq/L
   2. Urine Chloride
      1. See Above
6. References
   1. Arieff (1993) J Crit Illn 8(2): 224-46 [PubMed]
   2. Narins (1982) Am J Med 72:496 [PubMed]
   3. Narins (1980) Medicine 59:161-95 [PubMed]
   4. Ghosh (2000) Fed Pract p. 23-33
   5. Rutecki (Dec 1997) Consultant, p. 3067-74
   6. Rutecki (Jan 1998) Consultant, p. 131-42