B3-035 CBCL Hemolytic Anemia Flashcards
defect in RBC itself
intrinsic
defect/problem outside RBC, but affects RBC
extrinsic
RBC breakdown with massive release of free hemoglobin in circulation
intravascular
RBC breakdown in reticuloendothelial system cells with capture of hemoglobin
extravascular
extravascular hemolysis is due to
decreased flexibility of the RBC
**minor leak of hemoglobin still occurs
in extravascular hemolysis, serum free hemoglobin is
absent
in intravascular hemolysis, serum free hemoglobin is
present
in extravascular hemolysis, urine hemoglobin is
absent
in intravascular hemolysis, urine hemoglobin is
present
hypochromic, microcytic cells are associated with
thalassemia
normocytic, normochromic cells are associated with
anemia
shistocytes are associated with
microangiopathic hemolytic anemia
spherocytes are associated with
hereditary spherocytosis
warm autoimmune hemolytic anemia
RBC agglutination is associated with
cold autoimmune hemolytic anemia
sickle cell
sperocytes
shistocytes
RBC agglutination
structurally abnormal hemoglobin due to mutation in alpha or beta globin gene
hemoglobinopathy
hemoglobinopathy is [intravascular/extravascular] [intrinsic/extrinsic] [inherited/acquired]
extravascular, intrinsic, inherited
thalassemia is
[intravascular/extravascular] [intrinsic/extrinsic] [inherited/acquired]
extravascular, intrinsic, inherited
decreased production of alpha or beta chains due to mutations
thalassemia
membrane defect in cytoskeletal protein
hereditary spherocytosis
hereditary spherocytosis is [intravascular/extravascular] [intrinsic/extrinsic] [inherited/acquired]
extravascular, intrinsic, inherited [AD]
spherocytosis is due to
increased membrane rigidity with membrane loss
proteins affected by hereditary spherocytosis
ankyrin
spectrin
band 3
band 4.2
caused by decreased level of critical enzyme
G6PD deficiency
G6PD deficiency causes increased sensitivity to
oxidative stress
G6PD deficiency can be precipitated by
infection
drugs (primaquine)
foods (fava beans)
G6PD deficiency offers protection from
malaria
G6PD deficiency is [intravascular/extravascular] [intrinsic/extrinsic] [inherited/acquired]
intravascular [acute] and extravascular, intrinsic, and inherited [XR]
clonal disorder with mutation in phosphatidylinositol glycan complementation group A (PIGA) gene
paroxysmal nocturnal hemoglobinuria
PNH causes decreased expression of GPI linked membrane glycoproteins
CD55 and CD59
PNH causes increased ____________________ lysis
complement mediated
PNH is [intravascular/extravascular] [intrinsic/extrinsic] [inherited/acquired]
intravascular, intrinsic, acquired
PNH demonstrates acquired mutations. This puts the patient at risk for
transformation to hematopoietic neoplasm
IgG antibodies recognized by splenic macrophages –> membrane loss
Warm autoimmune hemolytic anemia
warm hemolytic anemia occurs around what temperature
37 degrees C
what shape are the RBCs in warm hemolytic anemia?
spherocytes
warm autoimmune hemolytic anemia can be secondary to
infection
drugs
lymphoproliferative disorders
warm autoimmune hemolytic anemia is [intravascular/extravascular] [intrinsic/extrinsic] [inherited/acquired]
extravascular
extrinsic
acquired
IgM antibodies causing RBC agglutination and complement mediated lysis
cold autoimmune hemolytic anemia
cold autoimmune hemolytic anemia can be secondary to
lymphoproliferative disorders
cold autoimmune hemolytic anemia is [intravascular/extravascular] [intrinsic/extrinsic] [inherited/acquired]
intravascular and extravascular
extrinsic
acquired
antibody coating RBCs can be detected by
antiglobulin (Coombs) test
traumatic hemolytic anemia is
[intravascular/extravascular] [intrinsic/extrinsic] [inherited/acquired]
intravascular
extrinsic
acquired
prosthetic heart valves can cause
traumatic hemolytic anemia
trauma due to widespread clots in microcirculation
microangiopathic hemolytic anemia
pathology of traumatic hemolytic anemia
shistocytes
thrombocytopenia
variable abnormal coagulation tests
direct Coombs test
detects antibody coating in RBCs
indirect Coombs test
detects antibody in plasma that can react with RBCs
identifies IgM or IgG antibodies coating RBCs
direct antiglobulin test (DAT)
can differentiate etiology of spherocytes
direct antiglobulin test (DAT)
reaction to preformed ABO antibodies is mediated by
IgM
**intravascular hemolysis if ABO incompatibility
reaction of alloantibodies to other RBC antigens is mediated by
IgG
**extravascular hemolysis over weeks
2 steps of serological tests
- sensitization: abs binding to RBCs surface Ag
- agglutination: sensitized RBCs are bridged together to form the lattice
antiglobulin test (AGT)
bridging between sensitized RBCs is not strong enough to cause agglutination
AHG then used to enhance agglutination
**required for clinically significant Ab detection
fixes complement and causes intravascular hemolysis
IgM
large, with 10 potential antigen binding sites
IgM
binds to Ags on adjacent RBCs, forming lattice clump
IgM
“cold antibody”, reacts best at 22 degrees C in the IS
IgM
smaller, 2 antigen binding sites
IgG
binds to antibodies on single RBC, so unable to bridge
IgG
“warm antibodies” react at 37 degrees C in AHG
IgG
needs AHG reagent to see agglutination
IgG
Phase 1: Immediate Spin Phase (IS)
patients serum is mixed with suspension of commercial reagent RBCs
centrifuged and examined for agglutination
if agglutination is present in the IS phase
cold antibodies, IgM
Phase 2: in test tube
37 degree incubation to detect warm Abs
incubate and centrifuge
Phase 3: tube, solid phase, gel
Add AHG, incubate, centrifuge, examine for agglutination
each negative AHG tube must be followed by
a control of IgG coated red cells
most important single test in RBC ab detection
AGT, Coombs
detects patient’s RBC that have already been sensitized with IgG or complement in vivo
direct antiblobulin test (DAT)
detects anti-RBCs abs in patients serum
in-vitro coating of RBCs with antibody or complement
indirect antiglobulin test (IAT)
in gel testing, a positive reading is
agglutinated cells remain at top of column