Ketonic diet in the management of pyruvate dehydrogenase deficiency.

Two brothers, aged 11 years 6 months and 2 years 3 months, with psychomotor and growth retardation, episodes of weakness, ataxia, ophthalmoplegia, and elevated levels of blood pyruvate were shown to have a deficiency in the pyruvate dehydrogenase complex (PDH). When they ate a diet high enough in fats to cause ketonemia but not acidosis, there was a fall in blood pyruvate levels, a decrease in the frequency and severity of the episodes of neurological deterioration, an increased rate of growth and development in the younger brother, and increased strength and endurance in the older one. The possibility of dietary treatment makes the early diagnosis of PDH deficiency more important. Determination of blood pyruvate and lactate levels following a standard glucose meal (glucose-pyruvate test) appears to be the most reliable screening test for this condition.