PE12.7 | B Complex Vitamins — Summary & Reflection

KEY TAKEAWAYS

B Complex Vitamins — Key Takeaways:

• The B complex family of 8 water-soluble vitamins serves as coenzymes in energy metabolism, DNA synthesis, and neural function. Small stores mean deficiency develops rapidly on a deficient diet.

• Thiamine (B1): coenzyme for pyruvate dehydrogenase; deficiency → beriberi (wet = infantile cardiac failure; dry = peripheral neuropathy). Treatment: thiamine IM/IV stat. Key trap: give thiamine BEFORE IV dextrose.

• Niacin (B3): precursor of NAD+/NADP+; deficiency → pellagra (3 Ds: Dermatitis/Diarrhoea/Dementia; Casal's necklace). Treatment: nicotinamide 100–300 mg/day.

• Folate (B9) and Cobalamin (B12): both cause megaloblastic anaemia with macrocytosis and hypersegmented neutrophils. Only B12 deficiency causes subacute combined degeneration of the spinal cord. Always check B12 before treating with folate alone.

• Pyridoxine (B6): coenzyme for GABA synthesis; deficiency → refractory neonatal seizures. INH depletes B6 → co-prescribe pyridoxine with all INH therapy.

• At-risk children: infants of vegan mothers (B12/B1), rice-based diet communities (B1), maize-dependent communities (B3), children on INH (B6), children with Crohn's (B12).

• Diagnostic tools: blood film (macrocytes + hypersegmented neutrophils), serum B12/folate, blood pyruvate/lactate, erythrocyte transketolase activity.

REFLECT

Think about the infants and children you may encounter in your community postings or outpatient paediatric rotation:

• If you see an infant under 6 months with unexplained cardiac failure, would you ask about the mother's diet and supplementation status? What one question could change your diagnostic thinking?

• Pellagra has been described in migrant children arriving in cities from maize-consuming tribal regions. How would you differentiate its photosensitive dermatitis from other skin conditions — and what community-level intervention could prevent it?

• If a child on TB treatment develops tingling in the feet — a preventable complication — whose responsibility is it to ensure pyridoxine was co-prescribed? How does this reflect your role in medication safety and patient education?

Jot down your reflections in your clinical log.