Classification of anemia for gastroenterologists

Table 2 Morphological classification

Microcytic anemia (MCV < 82 fL)

IDA

Thalassemia

Non thalassemic conditions associated with microcytosis

ACD (e.g. rheumatoid arthritis, Hodgkin’s lymphoma, chronic infection, neoplasia)

Sideroblastic anemia (e.g. hereditary, lead poisoning)

Normocytic anemia (MCV = 82-98 fL)

Nutritional anemia (iron deficiency, cobalamin y/o folate)

Anemia of renal insufficiency

Hemolytic anemia

Red cell intrinsic causes: membranopathy, enzymopathy, hemoglobinopathy

Red cell extrinsic causes: immune-mediated, microangiopathic, associated with infection, chemical agent (spider venoms), metabolic

ACD

Primary bone marrow disorder

Causes that are intrinsic to hematopoietic stem cells: bone marrow aplasia (idiopathic, PNH, Fanconi syndrome), pure red cell aplasia (acquired, congenital, Diamond-Blackfan syndrome), myelodysplastic syndrome

Extrinsic causes: drugs, toxins, radiation, viruses, immune-mediated, bone marrow infiltration (metastatic and lymphoma)

Macrocytic anemia (MCV > 98 fL)

Drugs (hydroxyurea, zidovudine, methotrexate)

Nutritional (vitamin B12 and folate deficiency)

Drug-induced hemolytic anemia

Dyserythropoiesis, myelodysplastic syndrome, clonal hematologic disorder

Hereditary hematologic disorders

Mild macrocytosis (MCV = 100-110 fL)

Reticulocytes

Excess alcohol intake, liver disease, smoking

Hypothyroidism, Waldenström’s macroglobulinemia

Copper deficiency, bone marrow aplasia, erythroblastopenic anemia

Down syndrome

Chronic obstructive pulmonary disease

MCV: Mean corpuscular volume.