Hemolytic Anemias

Epidemiology and Etiology:

• Extravascular hemolysis (more common)
• Generally caused by alterations that render the red cell less deformable
• Intravascular hemolysis
• Mechanical injury
• Heart valves
• Microcirculation thrombosis
• Repetitive physical trauma
• Marathon running
• Bongo drum beating
• Complement fixation
• Antibodies to red cell antigens
• Toxic injury
• Ex. clostridial sepsis

Common sites:

Gross features:

• Cholelithiasis (pigment gallstones) with chronic hemolysis

Histologic features:

• Bone marrow:
• Erythroid precursors (normoblasts) increased
• Peripheral blood:
• Reticulocytosis
• Hemosiderosis (spleen, liver, bone marrow)
• Extramedullary hematopoiesis (if severe anemia) (liver, spleen, lymph nodes)

Immunophenotype:

Marker:

Sensitivity:

Specificity:

Molecular features:

Other features:

• EPO elevated
• Unconjugated serum bilirubin
• Clinical features:
• Extravascular hemolysis:
• Anemia
• Splenomegaly
• Jaundice
• Intravascular hemolysis:
• Anemia
• Hemoglobinemia
• Hemoglobinuria
• Hemosiderinuria
• Jaundice

References:

• Kumar V, Abbas AK, Fausto N, Aster JC, eds. Robbins and Cotran Pathologic Basis of Disease, 8^th ed. (2010)