Rapid development of vitamin K deficiency in an adolescent boy receiving total parenteral nutrition following bone marrow transplantation

Vitamin K deficiency in children pre-bone marrow transplantation

This study examined the prevalence of vitamin K deficiency in children pre-bone marrow transplantation (BMT). Vitamin K status was measured by the PIVKA-II assay and prothrombin times. Blood samples were obtained before vitamin-containing TPN was infused. Results indicated that eight of 26 patients (31%) were vitamin K deficient; four cases were attributed to drug antagonism (phenytoin) and four were due to inadequate vitamin K intake, synthesis or malabsorption. Only one patient had a prolonged prothrombin time. Prothrombin time, in our study, is shown to be an ineffective screening tool to determine vitamin K status. All patients receiving phenytoin and chemotherapy are at increased risk of vitamin K deficiency.

Vitamina K: metabolismo e nutrição

O objetivo desta revisão foi discutir aspectos que envolvem a compreensão do metabolismo da vitamina K e os recentes avanços quanto ao papel da vitamina na nutrição humana. São abordadas questões sobre as fontes da vitamina, sua absorção, distribuição e metabolismo, recomendações dietéticas, avaliação do estado nutricional relacionado à vitamina K e ainda fatores que afetam sua concentração plasmática. Diante das novas evidências sobre a participação da vitamina K no metabolismo ósseo, pesquisas adicionais são necessárias a fim de identificar as possíveis conseqüências à saúde, a longo prazo, de deficiência subclínica desta vitamina. Pesquisadores e comitês futuros encontram um desafio no que se refere a investigar novos requerimentos nutricionais da vitamina.

Nutrition support in bone marrow transplant recipients

Bone marrow transplantation is a complex therapy designed as curative for a variety of malignant and nonmalignant diseases. It is a highly invasive procedure that uses high-dose chemotherapy and may also include radiation treatment. This results in immunosuppression that is often followed by infection, graft-vs-host disease, pulmonary complications, veno-occlusive disease of the liver, and metabolic and nutritional abnormalities. Parenteral nutrition has been the mainstay of nutrition support in patients undergoing bone marrow transplantation. Parenteral nutrition has not been uniformly successful in improving nutritional status or outcome. Enteral nutrition offers many theoretical advantages but is often not well tolerated. Coordinated efforts of the health care team are needed to optimize the nutrition support of these complicated cases.