Metabolic acidosis, increased anion gap


  • Gap >12 meq


  • Lactic acidosis
    • Type A (tissue hypoxia): cardiogenic, septic, or hemorrhagic shock; seizure; carbon monoxide or cyanide poisoning
    • Type B (nonhypoxic): hepatic or renal failure, intestinal ischemia, diabetes especially with metformin use, ketoacidosis, infection, leukemia or lymphoma, drugs (ethanol, methanol, salicylates, isoniazid), AIDS, idiopathic (usually in debilitated patients)
  • Diabetic ketoacidosis
  • Starvation ketoacidosis
  • Alcoholic ketoacidosis
    • Frequently with mixed disorders (10% have triple acid-base disorder)
    • Acid-base disorders in alcoholism include: three types of metabolic acidosis (ketoacidosis, lactic acidosis, or hyperchloremic acidosis from bicarbonate loss in urine from ketonuria); metabolic alkalosis from volume contraction and vomiting; respiratory alkalosis from alcohol withdrawal, pain, sepsis, or liver disease
  • Uremic acidosis (usually at GFR <20 mL/min)
  • Ethylene glycol toxicity
  • Methanol toxicity
  • Salicylate toxicity (mixed metabolic acidosis with respiratory alkalosis)
  • Other: paraldehyde, isoniazid, iron, rhabdomyolysis

See related DDx

Last updated: December 1, 2014