In the past, lactic acidosis syndrome was described as a very rare side effect of these medications leading to death in more than half of the cases despite aggressive medical care. This milder form is treatable and reversible if recognized early and if the offending medication is stopped. While it is unclear where the pathology is in this syndrome, some investigators feel that the dysfunction may be related to pathology in the liver. Being female and being over-weight are felt to be risk factors for developing this syndrome. Lactic acidosis syndrome and hyperlactatemia are felt to be caused by the toxic effect of NRTIs on mitochondrial function.
Mitochondria are subcellular organelles present in all cells except erythrocytes.
Thus, in the very simplest sense, mitochondrial dysfunction causes disease because the organism or tissue does not have enough energy to perform its given function. Because glucose cannot undergo oxidative phosphorylation, it is converted instead to lactic acid leading to accumulation of this acid in high levels in the body. Information from this mitochondrial DNA is needed to manufacture the proteins and enzymes needed for mitochondrial function including oxidative phosphorylation. The end result is that needed mitochondrial proteins and enzymes are not produced leading to decreased energy generation. This requires that you and your physician need to be aware of the existence of this syndrome in order to diagnose this early.