Module 5: Hemolytic Anemias Flashcards
Defects in RBC membranes causing hemolytic anemias:
Hereditary spherocytosis
Hereditary elliptocytosis
Hereditary acanthocytosis/abetalipoproteinemia
Hereditary stomatocytosis
Enzyme defects causing hemolytic anemias:
Glucose 6 phosphate dehydrogenase deficiency
Pyruvate kinase deficiency
Abnormal hemoglobins causing hemolytic anemias:
Sickle cell trait Sickle cell anemia Alpha thalassemia Beta thalassemia minor Beta thalassemia major (Cooley anemia)
Acquired intracorpuscular defect causing hemolytic anemia:
Paroxysmal nocturnal hemoglobinuria
Immune hemolytic anemias:
Due to alloantibodies (HDN, transfusion reactions)
Autoimmune hemolytic anemia (warm, cold)
Due to complement activation (paroxysmal cold hemoglobinuria)
What is hereditary spherocytosis?
Autosomal dominant intracorpuscular RBC membrane defect
Deficiency/abnormality of membrane proteins
Decreased SA:volume ratio
Cells become rigid
Hereditary spherocytosis: intra/exravascular hemolysis?
Extravascular
Major lab findings in hereditary spherocytosis:
Microspherocytes Polychromasia Increased osmotic fragility DAT negative Increased autohemolysis corrected with glucose or ATP Increased MCHC
What is hereditary elliptocytosis?
Autosomal dominant intracorpuscular RBC membrane defect
Deficiency of membrane cytoskeletal proteins
Hereditary elliptoocytosis: intra/exravascular hemolysis?
Extravascular
Major lab findings in hereditary elliptocytosis:
Enlarged spleen
Hyperbilirubinemia
25-95% elliptocytes
Spherocytes and polychromasia
General lab findings in hemolytic anemias
Hb decreased Hct decreased RBC count decreased Relic count increased Blood film: polychromasia, poikilocytosis
What is hereditary acanthocytosis/abetalipoproteinemia?
Intracorpuscular RBC membrane defect
Deficiency of beta lipoprotein
Sphingomyelin/lecithin ratio is increased
Hereditary acanthocytosis/abetalipoproteinemia: intra/exravascular hemolysis?
Extravascular
Major lab findings in hereditary acanthocytosis/abetalipoproteinemia:
Acanthocytes
Low ESR
Mechanical fragility increased
Cholesterol and triglycerides usually decreased
What is hereditary stomatocytosis?
Intracorpuscular RBC membrane defect
Increased passive permeability of Na and K causes net swelling of the cell (gain Na, lose K)
Hereditary stomatocytosis: intra/exravascular hemolysis?
Intravascular
Major lab findings in hereditary stomatocytosis:
10-30% stomatocytes
No spherocytes
Autohemolysis increased, partly corrected with ATP and glucose
Osmotic fragility increased
What is glucose 6 phosphate dehydrogenase deficiency?
Most common enzyme defect
Decreased G6PD –> increased NADPH –> decreased glutathione –>increased methemoglobin (oxidized hemoglobin)
Glucose 6 phosphate dehydrogenase deficiency: intra/exravascular hemolysis?
Intravascular
Major lab findings in glucose 6 phosphate dehydrogenase deficiency:
Bite cells and schistocytes Heinz bodies Polychromasia Decreased haptoglobin Autohemolysis increased, corrected with glucose Enzyme assay
What is pyruvate kinase deficiency?
Causes chronic anemia
Deceased ATP production, hemolysis due to failure of active transport and other ATP dependent reactions
Hereditary pyruvate kinase deficiency: intra/exravascular hemolysis?
Extravascular
Major lab findings in pyruvate kinase deficiency:
Increased 2,3 BPG Enlarged spleen Autohemolysis increased, corrected with ATP but not glucose No characteristic morphology Enzyme assay
What is sickle cell trait?
Hemoglobin A 55-85% Hemoglobin S 20-45% Heterozygous A and S On chromosome 11 Resistance to plasmodium falciparum
Hereditary sickle cell trait: intra/exravascular hemolysis?
Extravascular
Major lab findings in sickle cell trait:
Usually asymptomatic May see hypo chromic/microcytic anemia Target cells Decreased oxygen: crisis (sickle cell anemia) Hemoglobin electrophoresis
