SM_248b: Acquired Hemolytic Anemias Flashcards

1
Q

____ is premature destruction of RBCs

A

Hemolysis is premature destruction of RBCs

  • Normal RBC life span is 90-120 days
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2
Q

Hemolytic anemia occurs when ___

A

Hemolytic anemia occurs when rate of RBC destruction exceeds production

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3
Q

Describe the types of hemolytic anemias

A

Hemolytic anemias

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4
Q

Describe intracorpuscular hemolysis

A

Intracorpuscular hemolysis

  • Hemoglobinopathies: sickle cell anemia, hemoglobin C or E
  • Enzyme defects: G6PD deficiency, pyruvate kinase deficiency
  • Membrane abnormalities: hereditary spherocytosis / elliptocytosis, acanthocytosis (spur cell anemia), paraxosymal nocturnal hemoglobinuria
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5
Q

____ and ____ are intracorpuscular causes of hemolysis

A

Acanthocytosis (spur cell anemia) and paroxysmal nocturnal hemoglobinuria are intracorpuscular causes of hemolysis

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6
Q

Describe extracorpuscular hemolysis

A
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7
Q

____ and ____ are extracorpuscular causes of hemolysis

A

Immunologic and infectious are extracorpuscular causes of hemolysis

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8
Q

Describe lab features of hemolytic anemia

A

Lab features of hemolytic anemia

  • Anemia
  • Reticulocytosis, polychromasia
  • Decreased haptoglobin
  • Hemoglobinuria or hemosiderinuria
  • Indirect hyperbilirubinemia
  • Elevated LDH
  • Abnormal appearance of RBCs
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9
Q

These are ___

A

Normal RBCs

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10
Q

These are ____

A

Spherocytes

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11
Q

These are ____

A

Reticulocytes

  • Immature RBCs
  • No longer contain nucleus
  • Have residual RNA
  • Indicator of increased production of RBCs
  • Not specific for hemolysis
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12
Q

This is ___

A

Polychromasia

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13
Q

Intravascular hemolysis results from ___

A

Intravascular hemolysis results from direct mechanical damage to RBCs

  • Some immune-mediated hemolytic anemias, particularly complement-mediated destruction
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14
Q

Extravascular hemolysis occurs in the ___

A

Extravascular hemolysis occurs in the reticuloendothelial system

  • Mononuclear phagocytes, particularly in spleen and liver
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15
Q

Describe intravascular and extravascular hemolysis

A

Intravascular and extravascular hemolysis

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16
Q

Describe acquired hemolytic anemias

A

Acquired hemolytic anemias

  • Immune-mediated hemolytic anemia: warm or cold autoantibody, RBC alloantibodies
  • Traumatic: microangiopathic hemolytic anemia, cardiac valvular disease
  • Infections: malaria, babesiosis
  • Membrane disorders: paroxysmal nocturnal hemoglobinuria, acanthocytosis
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17
Q

Warm antibody type of autoimmune hemolytic anemia involves antibody reaction at ___ and ___ hemolysis

A

Warm antibody type of autoimmune hemolytic anemia involves antibody reaction at 37C and extravascular hemolysis

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18
Q

Cold antibody type of autoimmune hemolytic anemia involves antibody reaction at ___ and ___ hemolysis

A

Cold antibody type of autoimmune hemolytic anemia involves antibody reaction at 4C and intravascular hemolysis

  • Complement-mediated
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19
Q

____ is used to diagnose autoimmune hemolytic anemia

A

Direct Coombs test is used to diagnose autoimmune hemolytic anemia

  • Detects antibody or complement or RBCs
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20
Q

Direct Coombs test involves ____

A

Direct Coombs test involves anti-IgG / IgM / IgA or anti-complement binding to RBCs and causing clumping

21
Q

Indirect Coombs test involves ___

A

Indirect Coombs test involves antiglobulin serum binding to patient antibodies and causing clumping

22
Q

Describe warm-body hemolytic anemia

A

Warm body hemolytic anemia

  • Idiopathic
  • Lymphomas
  • Collagen vascular diseases: SLE
  • Drugs: alpha-methyldopa, penicillin, quinidine
  • Post-viral infections
  • Other: tumors
23
Q

Warm antibody hemolytic anemia pathophysiology involves ____ that are then____

A

Warm antibody hemolytic anemia pathophysiology involves IgG antibodies coating RBCs that are then removed by macrophages in spleen

  • 25% associated with underlying disease
24
Q

Describe lab findings of warm antibody hemolytic anemia

A

Warm antibody hemolytic anemia

  • Spherocytes / microspherocytes
  • Anemia
  • Reticulocytosis: nucleated RBCs
  • Indirect hyperbilirubinemia, elevated LDH, decreased haptoglobin
  • Coombs test: IgG usually postive, complement can be positive or negative
25
Q

Describe treatment of warm antibody hemolytic anemia

A

Warm antibody hemolytic anemia

  • Ensure adequate production of RBCs: folate, other vitamin deficiencies
  • RBC transfusion can be given if asymptomatic
  • Cessation of any suspect drugs
  • Immunosuppressive therapy: corticosteroids
  • Splenectomy for refractory cases
26
Q

Describe drug-induced immune hemolytic anemia

A

Drug-induced immune hemolytic anemia

  • Hapten / drug absorption: penicillin, high dose
  • Immune complex (neoantigen): quinidine, quinine, sulfonamides, isoniazid
  • Autoimmune: alpha-methyldopa, levodopa, procainamide
27
Q

___ is a critical step in hapten-induced hemolytic anemia

A

Drug binding to RBCs is a critical step in hapten-induced hemolytic anemia

  • Examples: penicillin, cephalosporins, tetracycline
28
Q

In immune complex (neoantigen) hemolytic anemia, ___

A

In immune complex (neoantigen) hemolytic anemia, antibody forms ternary complex with drug and RBC membrane component

  • Examples: quinine, quinidine, sulfonamides
29
Q

In autoimmune drug-induced hemolytic anemia, ___

A

In autoimmune drug-induced hemolytic anemia, drug stimulates production of anti-RBC autoantibody

  • alpha-methyldopa, levodopa, procainamide
30
Q

Describe cold antibody hemolytic anemia

A

Cold antibody hemolytic anemia

  • Cold agglutinin disease
  • Acute: mycoplasma infection, infectious mononucleosis
  • Chronic: idiopathic, lymphoproliferative disorder
  • Paroxysmal cold hemoglobinuria
31
Q

Describe cold reacting anitbodies

A

Cold reacting antibodies

  • Usually IgM antibodies
  • Can normally be present at very low titers in the serum and not clinically significant
  • Hemolysis depends on: antibody titer, thermal amplitude of Ab-Ag interaction, environmental temperature, complement fixation
  • Hemolysis is intravascular: complement-mediated lysis of RBCs
  • React with polysaccharides on the RBC surface
  • Anti-I: monoclonal gammopathy, Mycoplasma pneumoniae
  • Anti-i: lymphoma, infectious mononucleosis
  • Cold agglutinins associated with infections: frequently present in mycoplasma or infectious mononucleosis, hemolysis is rare
32
Q

Cold agglutinin disease occurs at age ___ and involves ___

A

Cold agglutinin disease occurs at age 50-70 and involves acrocyanosis

  • Acrocyanosis: cool extremities result in RBC agglutination in hands or feet
33
Q

Describe lab testing for cold agglutinin disease

A

Cold agglutinin disease lab testing

  • Peripheral smear: RBC agglutination, disaggregation of RBC on warming the blood
  • Hemoglobinemia, hemoglobinuria, hemosiderinuria
  • Indirect hyperbilirubinemia, elevated LDH, low haptoglobin
  • Coombs test positive with anti-C3 (complement) and negative for IgG
  • Cold agglutinin disease: thermal amplitude
34
Q

Describe therapy for cold agglutinins

A

Cold agglutinins treatment

  • Treat only if evidence of hemolysis
  • Supportive
  • Treat underlying disorde
  • Therapeutic plasma exchange to temporarily remove antibodies
  • Rituximab
35
Q

Alloimmune hemolytic diseases include ____ and ____

A

Alloimmune hemolytic diseases include

  • Alloimmune hemolysis in newborn: Rh (anti-D) hemolytic disease of the newborn, ABO incompatibility
  • Alloimmune hemolysis: transfusion-mediated reactions
36
Q

Rh hemolytic disease includes when ___, ___, and ___

A

Rh hemolytic disease includes when

  1. Mother is Rh negative
  2. Mother develops antibodies against Rh positive RBC from fetus during late pregnancy or delivery
  3. Antibodies affect fetus of subsequent pregnancies
37
Q

Severe anemia, jaundice, and hepatosplenomegaly after birth is ___

A

Severe anemia, jaundice, and hepatosplenomegaly after birth is Rh hemolytic disease

  • May cause intrauterine death (hydrops fetalis)
  • CBC with nucleated RBCs, reticulocytes, no spherocytes
  • Direct Coombs test is strongly positive
38
Q

ABO hemolytic disease occurs when ___, ___, and ___

A

ABO hemolytic disease occurs when

  1. Mom with group O and fetus with A or B blood type
  2. Mom’s anti-A or anti-B igG antibodies cross placenta
  3. Mild hemolysis

(may occur with first pregnancy)

39
Q

Anemia with reticulocytosis, microcytosis, and spherocytes is ___

A

Anemia with reticulocytosis, microcytosis, and spherocytes is ABO hemolytic disease

  • Less severe than Rh disease
  • Direct Coombs weakly positive
  • Indirect Coombs positive
40
Q

Describe treatment and prevention of Rh hemolytic disease and ABO hemolytic disease

A

Rh hemolytic disease and ABO hemolytic disease prevention and treatment

  • Prevention is key
  • Administration of anti-D immune globulin to Rh negative pregnant women for Rh hemolysis at first and subsequent pregnancies at 28 weeks gestation and when maternal-fetal blood exchange
  • Mother-child transfusions in utero peridelivery for ABO hemolysis
41
Q

Traumatic hemolytic anemia includes ____, ____, and ____

A

Traumatic hemolytic anemia includes microangiopathic hemolytic anemia, march hemoglobinuria, and cardiac valvular disease

42
Q

Paroxysmal nocturnal hemoglobinuria results from ___

A

Paroxysmal nocturnal hemoglobinuria results from mutations in phosphatidyl-inositol-glycan A (PIG-A)

  • Responsible for glycosylphosphatidylinositol (GPI) anchored protein deficiencies: anchors proteins to lipid bilayer
43
Q

Paroxysmal nocturnal hemoglobinuria results in ___

A

Paroxysmal nocturnal hemoglobinuria results in complement-mediated lysis of RBCs

44
Q

Describe paroxysmal nocturnal hemoglobinuria

A

Paroxysmal nocturnal hemoglobinuria

  • Chronic hemolytic anemia or pancytopenia
  • May have acute hemolysis at night and awaken to red urine (hemoglobinuria)
  • Subtypes depend on degree of decrease in membrane-anchored proteins
  • Major complication is thrombosis
  • Can lead to iron deficiency
  • Can evolve into aplastic anemia or myelodysplasia
45
Q
A
46
Q

Describe lab findings of paroxysmal nocturnal hemoglobinuria

A

Paroxysmal nocturnal hemoglobinuria lab findings

  • Normochromic, normocytic anemia
  • May have other cytopenias
  • Evidence of hemolytic anemia
  • Coombs test is negative
  • Flow cytometry demonstrates absent CD55 and CD59 expression
  • Ham’s test / sucrose hemolysis test: sucrose or uric acid added to RBCs leads to enhanced hemolysis
47
Q

Describe treatment for paroxysmal nocturnal hemoglobinuria

A

Paroxysmal nocturnal hemoglobinuria treatment

  • Mainly supportive: replace iron and folate
  • Eculizumab: antibody against C5, inhibits terminal complement activation
  • Anticoagulation for thrombosis
  • Allogeneic stem cell transplant is curative
48
Q

Describe spur cell anemia

A

Spur cell anemia

  • Liver disease
  • Membrane defect: excess cholesterol but normal phospholipid
  • Severe anemia and splenomegaly
  • Acanthocytosis
  • Splenectomy may help but most are too ill