A 10-year-old boy with chronic kidney disease due to posterior urethral valves (baseline eGFR 25 mL/min/1.73m²) presents for routine follow-up. His mother reports fatigue and poor appetite over the past month. On examination, he appears pale with normal growth parameters for his baseline. Labs show hemoglobin 8.5 g/dL, MCV 82 fL, ferritin 250 ng/mL, transferrin saturation 25%, and normal reticulocyte count. Stool occult blood is negative.
What is the most appropriate next step in management?
A. Blood transfusion
B. Bone marrow biopsy
C. Erythropoiesis-stimulating agent
D. IV iron therapy
E. Oral iron supplementation
Correct answer & Explanation:
Correct Answer: C — Erythropoiesis-stimulating agent
Explanation:
Why C is correct: This child has anemia of CKD, driven by inadequate renal erythropoietin production as GFR declines. His iron studies are already adequate (ferritin >100 ng/mL, TSAT >20%), ruling out iron deficiency as a contributing cause. With replete iron stores and no other identifiable cause, the standard of care is initiating an erythropoiesis-stimulating agent (ESA), such as epoetin alfa or darbepoetin, per KDIGO pediatric guidelines, once hemoglobin falls below the treatment threshold (~10 g/dL).
Why others are wrong:
- A — Transfusion is reserved for severe/symptomatic anemia (e.g., hemodynamic compromise) or ESA-refractory cases, not first-line for a stable outpatient with Hb 8.5.
- B — Bone marrow biopsy is unnecessary; the anemia is fully explained by CKD-related EPO deficiency, with a normocytic picture and no marrow failure features.
- D — IV iron is used when iron stores are deficient (low ferritin/TSAT) or to support suboptimal ESA response; this child’s iron studies are already adequate.
- E — Oral iron has poor absorption in CKD from hepcidin-mediated blockade and is unnecessary here since iron stores are replete.
