A 9-month-old exclusively breastfed infant from a vegan family presents with pallor, hypotonia, regression of milestones, macroglossia, and megaloblastic anemia. The diagnosis and the mechanism is:

• A Vitamin B12 deficiency — breastfed infant of vitamin B12-deficient vegan mother; B12 is found only in animal products and is critically low in vegan breast milk ✓
• B Folate deficiency — inadequate dietary folate in breast milk
• C Iron deficiency anemia — most common at 9 months in breastfed infants
• D Copper deficiency — inadequate copper in vegan diet

Explanation

Breastfed infants of strictly vegan mothers are at high risk for vitamin B12 deficiency because B12 is found exclusively in animal products, and vegan breast milk is severely B12-depleted. B12 deficiency in infants causes megaloblastic anemia, severe neurological regression (hypotonia, developmental regression), macroglossia, and elevated homocysteine/methylmalonic acid. Iron deficiency causes microcytic, not megaloblastic anemia. Folate deficiency causes megaloblastic anemia without neurological features. Treatment is parenteral B12 supplementation.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.