Lactic acid, an intermediary in carbohydrate metabolism, is predominantly derived from skeletal muscle and erythrocytes. The blood lactate concentration depends on the rate of produc-tion in these tissues and the rate of metabolism in the liver.
Lactic acidosis occurs in 2 clinical settings:
– type A (hypoxic), associated with decreased tissue oxygenation, such as shock, hypovolemia, and pulmonary insufficiency.
– type B (metabolic), associated with disease (diabetes mellitus, neoplasia, liver disease…), intoxication by drugs/toxins (ethanol, methanol, salicylates…), or inborn errors of metabolism.