What is the recommended treatment for pernicious anemia with neurological symptoms and glossitis?

• A. Oral vitamin B12 daily
• B. Intramuscular vitamin B12
• C. Intravenous iron therapy
• D. Oral folic acid only

Answer: (B)

Replenishing vitamin B12 reliably is essential when pernicious anemia causes neurologic symptoms and glossitis. In pernicious anemia, intrinsic factor deficiency impairs absorption of B12 from the gut, so oral supplementation may not suffice, especially when neurologic involvement is present. Giving B12 intramuscularly bypasses the gut and ensures rapid and complete repletion, which is critical for reversing neurologic deficits and glossitis.

A typical approach starts with high-dose injections to quickly restore stores, then switches to less frequent maintenance injections for life. For instance, a common regimen is 1000 mcg of cyanocobalamin intramuscularly daily for about a week, then weekly for several weeks, and eventually monthly thereafter. This method addresses both the hematologic deficiency and the neurological symptoms.

Intravenous iron therapy would target iron deficiency anemia, not B12 deficiency, so it isn’t appropriate here. Folic acid alone can correct anemia temporarily but does not treat the underlying B12 deficiency and can mask ongoing neurologic damage. Oral vitamin B12 alone is unreliable in pernicious anemia when neurologic symptoms are present, making intramuscular administration the best choice.