Metabolic Alkalosis

• Types
  1. Chloride responsive metabolic alkalosis
     1. Extracellular fluid contraction
     2. Saline responsive
  2. Chloride-resistant metabolic alkalosis
     1. Associated with excess mineralcorticoid
     2. Associated with Hypokalemia
     3. Saline unresponsive

   

   

• 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

   

   

• 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 mineralcorticoid 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

   

   

• Labs
  1. Arterial Blood Gas
     1. Arterial pH increased
     2. Serum bicarbonate increased
     3. PaCO2 increased
        1. PaCO2 rises 6 mmHg per 10 meq/L bicarbonate rise
        2. PaCO2 = 0.7 x HCO3 + 20 (+/- 1.5)
     4. Excess Anion Gap >30 mEq/L
  2. Urine Chloride
     1. See Above