Page 461 - First Aid for the USMLE Step 1 2020, Thirtieth edition [MedicalBooksVN.com]_Neat

Hematology and oncology ` hematology and oncology—Pathology Hematology and oncology ` hematology and oncology—Pathology SectIon III 417

Anemias
Anemias

Microcytic Normocytic Macrocytic
(MCV < 80 fL) (MCV 80–100 fL) (MCV > 100 fL)

Hemoglobin a ected (TAIL) Nonhemolytic Hemolytic Megaloblastic Nonmegaloblastic
Defective globin chain: (low reticulocyte index) (high reticulocyte index)
•Thalassemias •Iron deficiency (early) DNA a ected
Defective heme synthesis: •Anemia of chronic disease Defective DNA synthesis •Diamond-Blackfan anemia
•Anemia of chronic disease •Aplastic anemia •Folate deficiency •Liver disease
•Iron deficiency (late) •Chronic kidney disease •Vitamin B 12 deficiency •Alcoholism
•Lead poisoning •Orotic aciduria
Defective DNA repair
•Fanconi anemia

Intrinsic Extrinsic

Membrane defects •Autoimmune
•Hereditary spherocytosis •Microangiopathic
•Paroxysmal nocturnal •Macroangiopathic
hemoglobinuria •Infections
Enzyme deficiencies
•G6PD deficiency
•Pyruvate kinase deficiency
Hemoglobinopathies
•Sickle cell anemia
•HbC disease

Reticulocyte index Also called corrected reticulocyte count. Used to correct falsely elevated reticulocyte count
in anemia. Measures appropriate bone marrow response to anemic conditions (effective
erythropoiesis). High reticulocyte index (RI) indicates compensatory RBC production; low RI
indicates inadequate response to correct anemia. Calculated as:
RI = reticulocyte % × actual Hct/normal Hct
[normal Hct ≈ 45%]

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