SCDC – B12 Replacement — SCE Neurology MCQ

Correct answer: B — Alternate-day IM hydroxocobalamin until neurological recovery plateaus

The best answer is “Alternate-day IM hydroxocobalamin until neurological recovery plateaus”. Neurological B12 deficiency requires intensive parenteral replacement on alternate days until improvement plateaus, followed by maintenance appropriate to the irreversible cause. “Hydroxocobalamin 1 mg orally once monthly until paraesthesia resolves” is less appropriate because the dose, route and interval are inadequate for severe neurological deficiency due to malabsorption “Folic acid 5 mg daily as sole treatment before replacing vitamin B12” is less appropriate because folate alone can improve anaemia while neurological injury from B12 deficiency progresses “Hydroxocobalamin 1 mg intramuscularly once yearly from diagnosis” is less appropriate because annual treatment is too infrequent for initial correction or maintenance “Cyanocobalamin 50 micrograms orally for seven days without maintenance” is less appropriate because a brief low-dose oral course is inadequate for autoimmune-gastritis-related malabsorption

Reference: BNF: Hydroxocobalamin treatment summary. https://bnf.nice.org.uk/drugs/hydroxocobalamin/ NICE NG239: Vitamin B12 deficiency in over 16s — recommendations. https://www.nice.org.uk/guidance/ng239/chapter/Recommendations