Carnitine deficiency revisited

The question of why carnitine is low in various disease states remains incompletely answered. The most likely explanations center around failure of the tissue to take up or hold carnitine and increased renal loss. Many diseases exhibit variations on these two themes, and consequently, the distinction between primary and secondary carnitine deficiency syndromes is increasingly blurred. Presently, the clinician has little choice but to being a trial of carnitine therapy in situations in which the tissue carnitine concentration seems low enough to limit fatty acid oxidation. With the recognition that 'carnitine deficiency' does not constitute an etiologic diagnosis, a thorough search should be made for the biochemical lesion in each patient.