Pernicious anemia: New insights from a gastroenterological point of view

Table 2 Differential diagnosis of PA: other causes of macrocytic anemia and cobalamin deficiency

Other causes of macrocytic anemia	Other causes of cobalamin deficiency
Folate deficiency due to decreased intake, impaired absorption or increased requirements	Gastric causes of impaired absorption/mal-digestion:
Drugs (e.g. methotrexate, azathioprine, 6-mercaptopurine, acyclovir, 5-fluorouracil, phenobarbital)	Gastrectomy
Accelerated erythropoiesis: hemolytic anemia, response to hemorrhage	Corpus-predominant H pylori gastritis
Liver disease (alcoholic, advance cirrhosis, poor dietary intake)	Long-term proton pump inhibitor therapy
Hypoplastic anemia, myelodysplastic syndrome	Intestinal causes of impaired absorption:
Chronic obstructive pulmonary disease	Ileal disease or resection
	Blind loop syndrome
	Fish tapeworm
	Severe pancreatic insufficiency
	Decreased intake due to vegetarianism