Vitamin Deficiencies

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?

A 42-year-old male laborer from rural Odisha presents with night blindness, Bitot's spots on conjunctiva, and follicular hyperkeratosis on extensor surfaces. Which single investigation is most appropriate to confirm vitamin A deficiency?

A 42-year-old male construction worker from Uttar Pradesh presents with a 4-week history of dermatitis on sun-exposed areas (face, neck, hands), chronic diarrhea, and mood disturbance. On examination, he has a well-demarcated erythematous rash with scaling and lichenification in a glove-and-stocking distribution. Serum albumin is 2.8 g/dL. He reports a diet consisting mainly of polished rice and legumes. What is the most appropriate immediate management?