45 Macroangiopathic Hemolytic Anemias
Michelle To and Valentin Villatoro
Traumatic Cardiac Hemolytic Anemia
In this condition, hemolysis is due to mechanical trauma caused by prosthetic cardiac valves. High blood flow around the prosthetic causes red blood cells to fragment leading to intravascular hemolysis. Any damaged cells that do not hemolyze in circulation are removed by the spleen via extravascular hemolysis.1,2
Hemolytic anemia due to traumatic cardiac causes is uncommon and platelet count is not usually decreased drastically. Any hemolysis that occurs is often compensated by the bone marrow.1,2
Laboratory Findings for Traumatic Cardiac Hemolytic Anemia:2
CBC: PLT: Normal Hb: Decreased RETIC: Increased |
PBS: Schistocytes |
Other Tests: Unconjugated Bilirubin: Increased LD: Increased Haptoglobin: Decreased |
Exercise-induced Hemoglobinuria
Transient hemolysis that occurs due to stress caused by exercise. Most often due to activities involving contact with hard surfaces such as running. Red blood cells become damaged as they pass through small vessels. Anemia usually does not develop unless hemolysis is severe.1
Laboratory Findings for Exercise-induced Hemoglobinuria:2
CBC: Hb: Increased RETIC: Increased MCV: Slight increase |
PBS: Schistocytes are NOT present |
Other Tests: Unconjugated Bilirubin: Increased LDH: Increased Haptoglobin: Decreased Hemoglobinuria |
Thermal Injury
Hemolytic anemia can develop after thermal burns to the body. Degree of hemolysis is dependent on the amount of surface area affected. Hemolysis is due to direct thermal damage to the red blood cells.1
Laboratory Findings for Thermal Injury:1
CBC: Hb: Decreased |
PBS: Schistocytes Micro-Spherocytes |
Other Tests: Hemoglobinuria |
References:
1. Smith LA. Hemolytic anemia: nonimmune defects. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p.372–87.
2. Keohane EM. Extrinsic defects leading to increased erythrocyte destruction – nonimmune causes. In: Rodak’s hematology clinical applications and principles. 5th ed. St. Louis, Missouri: Saunders; 2015. p. 394-410.