Megaloblastic Anemia Secondary to Vitamin B12 Deficiency in an 11-Month-Old Infant: A Case Report

الملخص

Background: Megaloblastic anemia caused by vitamin B12 and folate deficiency is the most common cause of macrocytic anemia in the pediatric age group, leading to impaired DNA synthesis and ineffective erythropoiesis. Although iron deficiency anemia is the most common cause of anemia worldwide, any macrocytic anemia with pancytopenia should be considered megaloblastic anemia. Case presentation: An 11-month-old female infant presents with a 1-month history of repeated nonprojectile vomiting, decreased oral intake, significant weight loss, frequent bowel movements, and decreased urine output over the last 5 days. When she was admitted to hospital, she was pale and moderately dehydrated. Her investigation showed severe anemia: hemoglobin was 6.4 g/dL, MCV was 105.8 fl, and thrombocytopenia was present. Peripheral blood smear showed anisopoikilocytosis. The infant was exclusively breastfeeding and had a limited amount of table food intake. The infant has a history of maternal anemia during pregnancy. The infant was treated at the hospital with parenteral B12, and there was rapid clinical and hematological improvement; she was discharged home, and at 1 month follow-up, her hemoglobin and platelet count had significantly improved. Conclusion: Any infant presenting with macrocytic anemia and pancytopenia should be considered to have megaloblastic anemia, which is most often caused by vitamin B12 or folate deficiency, even in the absence of neurological symptoms. Early diagnosis and treatment lead to excellent recovery and prevent complications.