Vitamin Deficiencies

A 38-year-old woman from rural Bihar presents with a 6-month history of progressive weakness, paresthesias in both feet, and unsteady gait. On examination, she has loss of vibration and proprioception in lower limbs, positive Romberg sign, and hyporeflexia. Her hemoglobin is 9.2 g/dL with macrocytic indices (MCV 104 fL). Serum B12 level is 180 pg/mL (normal >200). She reports a predominantly vegetarian diet with rare egg consumption. What is the most appropriate next step in management?

A 52-year-old male construction worker from Rajasthan presents with a 3-month history of painful, swollen gums with bleeding, poor wound healing, and follicular hyperkeratosis on his lower extremities. He reports a diet of rice, dal, and occasional vegetables but no fresh fruits for the past 8 months due to financial constraints. Hemoglobin is 10.8 g/dL (normocytic). What is the most appropriate next step in management?

A 38-year-old woman from rural Maharashtra presents with a 6-month history of progressive weakness, numbness in her feet, and difficulty walking. On examination, she has loss of vibration sense and proprioception in the lower limbs, brisk reflexes, and a positive Romberg sign. Her diet consists mainly of polished rice and dal with minimal vegetables or fortified foods. Hemoglobin is 9.2 g/dL. Which vitamin deficiency is most likely responsible for her neurological findings?

A 52-year-old male laborer from rural Uttar Pradesh presents with a 4-month history of progressive dermatitis on his face, neck, and hands (areas exposed to sunlight), chronic diarrhea, and increasing irritability and poor memory. His diet consists mainly of corn and legumes with minimal vegetables, eggs, or meat. On examination, he has a sharply demarcated, hyperpigmented, scaly dermatitis in a 'glove and stocking' distribution on sun-exposed areas. His mental status is mildly impaired. What is the most likely diagnosis?

A 42-year-old man with a history of chronic diarrhea and malabsorption presents with angular cheilitis, glossitis, and seborrheic dermatitis of the nasolabial folds. Laboratory investigations show macrocytic anemia with hypersegmented neutrophils. Which single laboratory or clinical finding best distinguishes vitamin B₁₂ deficiency from folate deficiency in this patient?