Classification of anemia for gastroenterologists

Table 5 Causes of megaloblastic anemia

Cobalamin deficiency

Poor diet

Deficiency of intrinsic factor

Pernicious anemia

Total or partial Gastrectomy

Ingestion of caustic (lye)

Functional defect of intrinsic factor

Alteration of ileal (microenvironment)

Insufficient pancreatic protease activity

Inactivation enzyme (Sd. Zollinger-Ellison)

Competition for cobalamin

Alteration of ileal mucosa

Acquired

Surgical resection or by-pass

Regional enteritis (Crohn’s disease)

Tropical esprue

Celiac disease, Tuberculosis

Lymphomatous infiltration

Induced by drugs

Congenital

Sd Immerslund-Gräsbeck

Congenital transcobalamin II deficiency or abnormality

Congenital methylmalonic acidemia and aciduria

Hemodialysis

Urinary losses (congestive heart failure)

Folate deficiency

Dietary

Old age, infancy, poverty, alcoholism, chronic invalids, psychiatrically disturbed, scurvy and kwashiorkor

Excess utilization or loss

Physiologic: pregnancy and lactation, prematurity

Pathologic: Hematologic diseases

Malignant diseases

Inflammatory disease

Metabolic disease

Excess urinary loss, congestive heart failure, active liver disease

Hemodialysis, peritoneal dialysis

Malabsorption

Congenital

Anti-folate drugs

Alcoholism

Tropical sprue, gluten-induced enteropathy

Extensive jejune resection, Crohn’s disease, partial gastrectomy, systemic bacterial infection, Whipple’s disease

Congenital abnormalities of folate metabolism

Cyclohydrolase, methionine synthetase

Combined deficit of folate and cobalamin

Celiac disease

Regional enteritis (Crohn’s disease)

Congenital disorder of DNA synthesis

Disorders of DNA synthesis induced by drugs

Anti-folate

Purine antagonists

Pyrimidine antagonists

Alkylating

Eritroleucemia