A 10-month-old exclusively breastfed infant whose mother is a strict vegetarian presents with failure to thrive, developmental regression, and megaloblastic anemia. Serum vitamin B12 is 80 pg/mL (normal >200 pg/mL). The MOST appropriate immediate management includes:

• A Oral cyanocobalamin 1 mg daily for 1 month
• B Folic acid supplementation alone at 5 mg/day
• C Intramuscular hydroxocobalamin 1 mg followed by monthly maintenance ✓
• D Breast milk supplementation with fortified formula only

Explanation

Infantile vitamin B12 deficiency from maternal deficiency in breastfeeding vegetarian mothers requires parenteral hydroxocobalamin because oral absorption is unreliable when intrinsic factor-mediated absorption may also be compromised and deficiency is severe. Hydroxocobalamin is preferred over cyanocobalamin as it binds more avidly to plasma proteins and has longer retention. Folic acid alone masks the hematological features but worsens neurological damage. The developmental regression may not fully recover, emphasizing the need for early treatment.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.