Infant with megaloblastic anemia and vitamin B12 deficiency born to a mother after total gastrectomy for gastric cancer: A case report

Abstract

An eight-month-old boy was referred to our hospital after pancytopenia was detected after an episode of fever. Laboratory testing revealed pancytopenia (WBC, 3300/μL; Hb, 4.5 g/dL; PLT, 26,000/μL). Bone marrow examination demonstrated dysplastic changes in all cell lineages, particularly megaloblastic changes in the erythroid lineage. Serum vitamin B12 was undetectable, leading to a diagnosis of vitamin B12-deficiency megaloblastic anemia. A detailed reassessment of the medical, family, and dietary histories revealed that the patient’s mother had undergone total gastrectomy for gastric cancer five years previously, without post-operative vitamin B12 supplementation. The patient had been exclusively breastfed, and weaning had barely commenced. Although mecobalamin supplementation rapidly corrected the hematological abnormalities, developmental regression, cerebral atrophy, and epilepsy persisted. Maternal vitamin B12 deficiency post-gastrectomy can result in irreversible neurological damage in infants, underscoring the importance of postoperative vitamin B12 supplementation in females of reproductive age and of interdisciplinary collaboration among obstetrics, surgery, and pediatrics departments.