A 16-month-old full-term girl is brought to the office to establish well-child care. The patient's family recently moved to the area and they have no concerns about her development. The patient weaned from breastfeeding at age 12 months, and her current diet mainly consists of whole cow's milk. She has no chronic medical conditions and takes no medications. She was born to a 24-year-old primigravida Greek woman and a 30-year-old African American man. The patient's father has sickle cell trait and her first cousin has sickle cell anemia; maternal family history is noncontributory. Physical examination reveals pallor of the conjunctivae but is otherwise unremarkable. Laboratory results are as follows: Hemoglobin electrophoresis reveals 40% HbS and 60% HbA. Which of the following is the most likely cause of this patient's anemia?

Question

A 16-month-old full-term girl is brought to the office to establish well-child care.  The patient's family recently moved to the area and they have no concerns about her development.  The patient weaned from breastfeeding at age 12 months, and her current diet mainly consists of whole cow's milk.  She has no chronic medical conditions and takes no medications.  She was born to a 24-year-old primigravida Greek woman and a 30-year-old African American man.  The patient's father has sickle cell trait and her first cousin has sickle cell anemia; maternal family history is noncontributory.  Physical examination reveals pallor of the conjunctivae but is otherwise unremarkable.  Laboratory results are as follows:  Hemoglobin electrophoresis reveals 40% HbS and 60% HbA.  Which of the following is the most likely cause of this patient's anemia?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c165_8996_8f63_9b6fd3574731_MD0005_00 This patient's anemia is most likely caused by iron deficiency. In children age >1, excessive milk intake (>24 oz/day) and low intake of iron-rich foods (eg, meats, cereals) contribute to the development of iron deficiency anemia. Given the high prevalence of iron deficiency in children age <2, these findings are sufficient to begin an empiric trial of iron supplementation. Iron deficiency is typically diagnosed based on clinical history and low hemoglobin. However, in patients with a family history of hemoglobinopathy (eg, sickle cell anemia), hemoglobin electrophoresis must be ordered. The presence of HbA and HbS in a 60:40 ratio, respectively, is consistent with sickle cell trait, which is generally asymptomatic and not a cause of anemia and microcytosis. This patient's microcytic anemia (low mean corpuscular volume) with an elevated red cell distribution width is most likely due to iron deficiency anemia. (Choice A) Alpha thalassemias are characterized by the presence of Hb Barts (4 gamma chains) on electrophoresis, not seen in this patient. (Choice B) Anemia of chronic disease is a normocytic, normochromic anemia that occurs in patients with chronic medical conditions (eg, renal failure, rheumatoid arthritis). (Choice C) Beta thalassemias are due to mutations in the beta globin genes; they are not associated with the presence of HbS. Sickle-beta thalassemia is comprised predominantly of HbS with <30% HbA. HbF and HbA2 are also typically elevated. (Choice D) HbSC is a less-severe variant of sickle cell disease characterized by a mild normocytic anemia. Hemoglobin electrophoresis showing almost equal amounts of HbS and HbC is diagnostic. Educational objective: Iron deficiency, commonly caused by excessive milk intake and insufficient iron-rich foods in young children, results in a microcytic anemia with an elevated red cell distribution width. The presence of HbA and HbS in a 60:40 ratio, respectively, on hemoglobin electrophoresis is consistent with sickle cell trait, which is asymptomatic and does not cause anemia. References: Iron deficiency and other types of anemia in infants and children. (http://www.ncbi.nlm.nih.gov/pubmed/26926814) Evaluation of anemia in children. (http://www.ncbi.nlm.nih.gov/pubmed/20540485)

A 16-Month-Old Full-Term Girl Is Brought to the Office to Establish