Intermittent-relapsing pyruvate dehydrogenase complex deficiency: a case with clinical, biochemical, and neuroradiological reversibility.

Pyruvate dehydrogenase complex (PDHC) deficiency causes encephalomyopathies, of which there are four major categories: (1) neonatal encephalopathy with lactic acidosis; (2) an early infantile form, which (3) at times resembles Leigh syndrome; and (4) a later-onset form. Long-term clinical and radiological follow-up is still incompletely elucidated. We report a 12-year-old male with intermittent-relapsing PDHC deficiency who presented with three typical acute episodes of metabolic decompensation over 7 years. Neuroimaging showed reversible signal abnormalities in the basal ganglia, inferior olivary nuclei, periaqueductal grey matter, and dentate nuclei, with evidence of lactate on magnetic resonance spectroscopy. Molecular analysis of PDH1A revealed a novel hemizygous c.1045G>A mutation, predicting a p.A349T missense mutation. He was treated with thiamine supplementation and, while on this regimen, he experienced several intercurrent febrile episodes without neurological compromise. This case report stresses the importance of performing neuroimaging during acute clinical episodes because brain lesions in PDHC deficiency may be transient and reversible, and false-negative results may mislead the diagnosis and delay the treatment.

Effect of carnitine supplementation on lipid profile and anemia in children on chronic dialysis.

We prospectively evaluated the effects of L-carnitine supplementation on plasma free carnitine (FC) levels, serum lipid profile, and erythropoietin (rhEPO) requirement in 24 children treated with peritoneal dialysis (PD; n=16) or hemodialysis (HD; n=8). The study was divided into a 3-month observation period, and a 3-month treatment period during which patients received 20 mg/kg per day of L-carnitine given orally. Clinical, biochemical, and hematological data were collected every 3 months. FC levels were measured in plasma and peritoneal dialysate by tandem mass spectrometry. There were no statistically significant changes in lipid levels, hemoglobin, or rhEPO requirements during the course of the study. Fifteen patients (13 PD, 2 HD) had plasma FC levels measured before and after treatment; FC levels increased from 32.1 +/- 14.1 micromol/l to 80.9 +/- 38.7 micromol/l (P<0.001). In PD patients, dialysate FC losses increased from 106 +/- 78 micromol/day at baseline to 178 +/- 119 micromol/day after supplementation. Positive correlations between FC plasma levels and dialysate levels (R=0.507) or daily excretion (R=0.603) were found after treatment. In our case series, an oral dose of 20 mg/kg per day of L-carnitine restored FC levels and produced a positive carnitine balance with no significant effects on hematological parameters or lipid profile over a 3-month period. Prolonged treatment duration may be required to obtain significant results.

Severe lactic acidosis due to thiamine deficiency in a patient with B-cell leukemia/lymphoma on total parenteral nutrition during high-dose methotrexate therapy.

An 11-month-old girl with B-cell leukemia/lymphoma developed profound lethargy due to severe lactic acidosis during chemotherapy and total parenteral nutrition (TPN). Initial treatment with NaHCO3 was ineffective. Treatment with a vitamin cocktail (OH-cobalamin, pyridoxine, thiamine, riboflavine, biotin, carnitine) at pharmacologic doses rapidly improved the child's clinical and laboratory status. Lactic acidosis was caused by an impairment of pyruvate dehydrogenase complex, which was due to lack of its necessary cofactor thiamine in the TPN. This case report indicates that lactic acidosis may be a front-line diagnosis in patients on TPN with lethargy and outlines the need for monitoring thiamine supply in TPN.