A 7-year-old girl with chronic anemia has peripheral smear showing numerous densely stained spherical cells lacking central pallor. Reticulocyte count is 8 percent, indirect bilirubin is elevated, and direct antiglobulin (Coombs) test is negative. Eosin-5-maleimide binding test shows reduced mean channel fluorescence. Which associated finding supports the need for folic acid supplementation during intercurrent illness?

• A Autoimmune neutropenia
• B Fava bean ingestion causing acute intravascular hemolysis
• C Iron overload from repeated transfusion
• D Parvovirus B19 infection causing transient aplastic crisis ✓

Explanation

Spherocytes without central pallor, high reticulocytes, negative Coombs test, and reduced eosin-5-maleimide fluorescence establish hereditary spherocytosis, caused by spectrin, ankyrin, band 3, or protein 4.2 defects. Parvovirus B19 selectively infects erythroid precursors and precipitates aplastic crisis, during which folate demand rises sharply, hence supplementation. Fava bean hemolysis indicates G6PD deficiency, chronic transfusion relates to thalassemia major, and autoimmune neutropenia is unrelated to this membrane defect.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.