Q: All of the following are causes of D-lactic acidosis except?

A) Short gut syndrome
B) Diabetic ketoacidosis
C) Propylene glycol 
D) Metformin



Answer: D

D-lactic acidosis is the most uncommon of Type A, B or D Lactic acidosis. It can be seen in people with short gut syndrome consuming high carbohydrate diet. Large amounts of carbohydrate gets fermented by intestinal bacteria and produce D-lactic acidosis. By default, humans metabolize D-lactic acid very slowly, and causes high plasma D-lactate levels and consequently metabolic acidosis. Other major reason of D-lactic acidosis in ICUs is infusion of propylene glycol, which is use as a solvent for many intravenous medications. D-Lactic acidosis also occurs in diabetic ketoacidosis via accumulating metabolites.

Metformin causes Type B lactic acidosis which is due to mitochndrial dysfunction. Other well-known drug to in ICU to do this is Linezolid.

Type A lactic acidosis is from ischemia and anaerobic metabolism of cells.