Carnitine deficiency among hospitalized pediatric patients: A retrospective study of critically ill patients receiving extracorporeal membrane oxygenation therapy.

BACKGROUND: The metabolic demands associated with critical illness place patients at risk for nutrition deficits. Carnitine is a small molecule essential for fatty acid oxidation and gluconeogenesis. Secondary carnitine deficiency can have clinically significant complications and has been observed anecdotally in patients receiving extracorporeal membrane oxygenation (ECMO) therapy at our institution. Guidelines for monitoring and supplementing carnitine are lacking. This retrospective study determined whether critically ill pediatric patients receiving ECMO have an increased risk of carnitine deficiency. METHODS: Acylcarnitine analysis was performed on residual specimens from patients who received ECMO therapy. The control data were a convenience sample gathered by chart review of patients who had been tested for carnitine during a hospitalization. RESULTS: Acylcarnitines were measured in 217 non-ECMO patients and 81 ECMO patients. Carnitine deficiency, based on age-specific reference ranges, was observed in 41% of ECMO cases compared with 21% of non-ECMO cases. Multivariable analysis of age-matched patients identified that the odds of carnitine deficiency were significantly lower among patients on the floor compared with ECMO patients (odds ratio, 0.21; 95% CI, 0.10-0.44). Age-specific frequency of qualitative carnitine deficiency ranged from 15% (patients >5 years old) to 56% (patients 1 week to 1 month old) in ECMO patients and 15% (patients >5 years old) to 34% (patients 1-5 years old) in non-ECMO patients. CONCLUSION: In this study, ECMO patients were carnitine deficient more frequently compared with other inpatients, with the highest rates of deficiency among ECMO patients between 1 week and 1 month old.

Tutorial: Triheptanoin and Nutrition Management for Treatment of Long-Chain Fatty Acid Oxidation Disorders.

BACKGROUND: Patients with severe long-chain fatty acid oxidation disorders (LC-FAODs) experience serious morbidity and mortality despite traditional dietary management including medium-chain triglyceride (MCT)-supplemented, low-fat diets. Triheptanoin is a triglyceride oil that is broken down to acetyl-coenzyme A (CoA) and propionyl-CoA, which replenishes deficient tricarboxylic acid cycle intermediates. We report the complex medical and nutrition management of triheptanoin therapy initiated emergently for 3 patients with LC-FAOD. METHODS: Triheptanoin (Ultragenyx Pharmaceutical, Inc, Novato, CA, USA) was administered to 3 patients with LC-FAOD on a compassionate-use basis. Triheptanoin was mixed with non-MCT-containing low-fat formula. Patients were closely followed with regular cardiac and laboratory monitoring. RESULTS: Cardiac ejection fraction normalized after triheptanoin initiation. Patients experienced fewer hospitalizations related to metabolic crises while on triheptanoin. Patient 1 has tolerated oral administration without difficulty since birth. Patients 2 and 3 experienced increased diarrhea. Recurrent breakdown of the silicone gastrostomy tube occurred in patient 3, whereas the polyurethane nasogastric tube for patient 2 remained intact. Patient 3 experiences recurrent episodes of elevated creatine kinase levels and muscle weakness associated with illness. Patient 3 had chronically elevated C10-acylcarnitines while on MCT supplementation, which normalized after initiation of triheptanoin and discontinuation of MCT oil. CONCLUSIONS: Triheptanoin can ameliorate acute cardiomyopathy and increase survival in patients with severe LC-FAOD. Substituting triheptanoin for traditional MCT-based treatment improves clinical outcomes. MCT oil might be less effective in carnitine-acylcarnitine translocase deficiency patients compared with other FAODs and needs further investigation.