Table 1.

Causes of severe metabolic acidosis

General MechanismSpecific Clinical Examples
True HCO3 deficit
    kidneyRenal tubular acidosis
    gastrointestinalDiarrhea
H+ gain
    exogenous acidNH4Cl administration, toxins
    abnormal lipid metabolismDiabetic ketoacidosisa
    abnormal carbohydrate metabolismLactic acid
    normal protein metabolismUremic acidosis
  • a Also a component of true HCO3 deficit because ketone bodies ("potential" HCO3) are lost in the urine both before and after admission.