Table 2.

Teaching points

A mitochondrial disorder should be suspected in patients with unexplained lactic acidosis.

In a patient with unexplained lactic acidosis, it is important to be aware of mitochondrial disorder and to obtain a careful clinical history and physical examination of possible underlying mitochondrial disorder. Certain drugs, such as metformin, can worsen the lactic acidosis. An underlying predisposition should be suspected if lactic acidosis develops in the setting of normal kidney function and on a standard dose of metformin.

Hypokalemia associated with lactic acidosis.

Unlike inorganic acids that are associated with hyperkalemia, lactic acidosis results in an inward shift of potassium and hypokalemia. This is due to increased activity of Na+-K+-ATPase pump related to the low intracellular pH that develops from lactic acidosis.