A 3-month-old infant presents with severe pallor. Hemoglobin is 4.5 g/dL with macrocytosis (MCV 112 fL) and absolute reticulocytopenia. WBC and platelet counts are normal. Bone marrow shows marked reduction of erythroid precursors only. Erythrocyte adenosine deaminase activity is elevated. Which feature favors this diagnosis over transient erythroblastopenia of childhood?

• A Onset after 2 years of age following a viral illness
• B Onset before 6 months of age with elevated adenosine deaminase ✓
• C Neutropenia with thrombocytopenia
• D Spontaneous recovery within 4 weeks

Explanation

Congenital pure red cell aplasia with macrocytosis, elevated erythrocyte adenosine deaminase, and onset in infancy indicates Diamond-Blackfan anemia, often accompanied by short stature and skeletal anomalies such as thumb abnormalities. Transient erythroblastopenia of childhood typically begins after the first year, follows a viral trigger, shows normocytic red cells with normal adenosine deaminase, and resolves spontaneously within weeks. Both conditions spare the myeloid and megakaryocytic lineages, so option C excludes neither.

Reference: Nelson Textbook of Pediatrics, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.