RESUMEN
BACKGROUND: Very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) is a rare autosomal recessive disorder of fatty acid metabolism. Its clinical presentation includes hypoketotic hypoglycemia and potentially life-threatening multiorgan dysfunction.Therefore, the cornerstone of management includes avoiding fasting, dietary modification, and monitoring for complications. The co-occurrence of type 1 diabetes mellitus (DM1) with VLCADD has not been described in the literature. CASE REPORT: A 14-year-old male with a known diagnosis of VLCADD presented with vomiting, epigastric pain, hyperglycemia, and high anion gap metabolic acidosis. He was diagnosed with DM1 and managed with insulin therapy while maintaining his high complex carbohydrate, low long-chain fatty acids diet with medium-chain triglyceride supplementation. The primary diagnosis (VLCADD) makes the management of DM1 in this patient challenging as hyperglycemia related to the lack of insulin puts the patient at risk of intracellular glucose depletion and hence increases the risk for major metabolic decompensation.Conversely, adjustment of the dose of insulin requires more attention to avoid hypoglycemia. Both situations represent increased risks compared to managing DM1 alone and need a patient-centred approach, with close follow-up by a multidisciplinary team. CONCLUSION: We present a novel case of DM1 in a patient with VLCADD. The case describes a general management approach and highlights the challenging aspects of managing a patient with two diseases with different potentially paradoxical life-threatening complications.