Tuesday, October 8, 2013

Type B Lactic Acidosis

Nice case report in AJKD recently raised the issue of Type B Lactic Acidosis. Lactic acidosis occurs when there is excessive anaerobic glycolysis or decreased removal of lactate from the circulation. Classically, Type A lactic acidosis is related to tissue hypoperfusion resulting in an increase in anaerobic glycolysis. Type B lactic acidosis occurs despite the presence of sufficient oxygen for aerobic glycolysis. There are a number of important causes:

Nucleoside Reverse Transcriptase Inhibitors
Enzyme Deficiencies
Pyruvate carboxylate
Pyruvate Dehydrogenase
Oxidative Phosphorylation Defects
Other Disorders
Kidney Failure
Liver Failure
Thiamine Deficiency

The case report in AJKD was a patient with myeloma who developed a severe lactic acidosis. The preference of tumor cells for anaerobic glycolysis has been known since the 1920s and is called the Warburg Effect. It is thought to be due to a combination of increased IGF and TGF-alpha production by tumor cells and thiamine deficiency which is common in patients with malignancies. The discussion in the case report gives a nice summary of the literature.

1 comment:

B Stewart said...

Interesting, but the Warburg effect describes the phenomenon of aerobic glycolysis: the dependence of tumour cells on high rates of relatively inefficient glycolysis to meet their energy requirements even in the presence of a normal oxygen tension which would permit oxidative phosphorylation in normal cells.