Intravascular hemolysis and methemoglobinemia from high dose vitamin C

Abstract

Background: Vitamin C is often used by complementary and alternative medicine practitioners for its antioxidant properties. We describe a case of severe hemolytic anemia and methemoglobinemia paradoxically resulting from an oxidative stress of high dose vitamin C in a patient with previously undiagnosed glucose-6-phosphate dehydrogenase (G6PD) deficiency. Case Presentation: A 47-year-old man presented with severe hemolytic anemia and methemoglobinemia days after receiving 395 g of intravenous (IV) vitamin C at an alternative medicine practice. He was managed conservatively with transfusions and his hemolysis subsided after several days. His G6PD level, measured months after his presentation, was deficient at 0.4 units/g. Conclusion: While vitamin C is often considered an antioxidant, its utilization in tissues produces its oxidized form (dehydroascorbic acid) which depletes intra-erythrocyte stores of glutathione. Patients with G6PD deficiency have reduced abilities to restore intracellular glutathione, placing them at risk for oxidative stress, and subsequent hemolysis that can be life threatening.