A patient with dementia, dermatitis, and diarrhea.
Niacin = Vitamin B3
Isoniazid treatment causes both deficiency of Niacin and Pyridoxine (Vit B6). Watch out for Niacin deficiency in patients on isoniazid.
Folate (vitamin B9) deficiency typically presents with a sore tongue (glossitis), weakness, fatigue, and anemia.
Vitamin B12 (cobalamin) deficiency (D) typically presents with paresthesias, ataxia, and megaloblastic anemia (eg, weakness, fatigue, easy bruising).