A 13-year-old girl is brought to the clinic by her mother because the girl has been increasingly tired over the last several months. The patient's family is from Greece, and her mother and maternal uncles have chronic anemia. Menarche was 1 year ago. Menses occur regularly each month, lasting 5-6 days with heavy bleeding and passage of clots, requiring her to wake up multiple times each night to change pads. The patient is a vegetarian but occasionally eats eggs. Her family lives in a neighborhood that was built in the 1980s. Vital signs are normal. The patient appears pale. The lungs are clear to auscultation. A soft systolic ejection murmur is heard in the pulmonic area. S1 and S2 are normal, and diastole is quiet. The remainder of the physical examination is normal. Complete blood count shows: Which of the following is the best next step in evaluation of this patient?

Question

A 13-year-old girl is brought to the clinic by her mother because the girl has been increasingly tired over the last several months.  The patient's family is from Greece, and her mother and maternal uncles have chronic anemia.  Menarche was 1 year ago.  Menses occur regularly each month, lasting 5-6 days with heavy bleeding and passage of clots, requiring her to wake up multiple times each night to change pads.  The patient is a vegetarian but occasionally eats eggs.  Her family lives in a neighborhood that was built in the 1980s.  Vital signs are normal.  The patient appears pale.  The lungs are clear to auscultation.  A soft systolic ejection murmur is heard in the pulmonic area.  S1 and S2 are normal, and diastole is quiet.  The remainder of the physical examination is normal.  Complete blood count shows:  Which of the following is the best next step in evaluation of this patient?

Quizplus · Accepted Answer

11ec25c8_d6ae_a824_bc81_5546be1bcff0_MD0003_00 Iron deficiency and thalassemia are the most common causes of microcytic anemia (mean corpuscular volume <80 µm³). Both present with fatigue and pallor; however, a history of prolonged bleeding (eg, heavy menses) or poor dietary iron intake raises suspicion for iron deficiency anemia (IDA). Distinguishing laboratory findings of IDA include decreased erythrocyte count (inadequate synthesis) and elevated red cell distribution width due to variable iron levels available throughout the day. In addition, IDA may be associated with reactive thrombocytosis (platelets >400,000/mm³) in response to low red blood cell count. This change is due to megakaryocytes and erythrocytes sharing a common progenitor cell. Although thalassemia should be on the differential diagnosis for a patient of Greek ethnicity with a family history concerning for an inherited thalassemia, this patient also has signs of IDA (heavy menses, decreased erythrocytes, thrombocytosis). Therefore, iron studies are the best next step. Correction of IDA is necessary prior to evaluation of thalassemia with hemoglobin electrophoresis because concomitant iron deficiency can lower hemoglobin A2 and mask the diagnosis (Choice B). (Choice A) Bone marrow biopsy should be considered in patients with more than 2 abnormal cell lines (eg, anemia, leukopenia, thrombocytopenia) to evaluate for acute leukemia or aplastic anemia. Because this patient has isolated anemia and related symptoms, bone marrow biopsy is not yet indicated. Iron studies are also a noninvasive first step in contrast to bone marrow biopsy. (Choice D) Lead poisoning can cause microcytic anemia in children with risk factors for lead exposure (eg, housing built before 1978, eating dirt/paint chips). In contrast, this patient's home was built in the 1980s. (Choice E) Vitamin B₁₂ deficiency is a macrocytic anemia more prevalent in patients with a vegan diet. Educational objective: Iron studies are performed prior to hemoglobin electrophoresis in patients with microcytic anemia suspicious for iron deficiency (eg, heavy menses, low erythrocyte count, reactive thrombocytosis) and concomitant thalassemia (eg, Greek origin, family history). References: Coexisting iron deficiency anemia and beta thalassemia trait: effect of iron therapy on red cell parameters and hemoglobin subtypes. (http://www.ncbi.nlm.nih.gov/pubmed/25006473) Clinicohematological study of thrombocytosis. (http://www.ncbi.nlm.nih.gov/pubmed/20532684)

A 13-Year-Old Girl Is Brought to the Clinic by Her