normocytic hemolytic anemia Flashcards
RBC hemolyisis → ↑ Hb in blood
↓ serum haptoglobin: binds free Hb in blood so it can be recycled, prevents breakdown to bilirubin
RBC hemolyisis → ↑ LDH in blood
↑ LDH (lactate dehydrogenase, lot in RBCs): pyruvate → lactate
intravascular hemolysis
↑ unconjugated bilirubin → jaundice
↑ LDH (lactate dehydrogenase, lot in RBCs): pyruvate → lactate
extravascular hemolysis
defect of proteins that interact with RBC membrane + cytoskeleton: ankyrin, spectrin (gives biconcave shape + flexibility) → RBC spheres
spleen recognizes + removes abnormal RBCs → splenomegaly
hereditary spherocytosis
↓ G6PD → ↓ glutathione → RBC sensitive to oxidative damage → hemolysis
back pain + hemoglobinuria few days after start DRUG
extravascular + intravascular hemolysis
resistant to malaria
G6PD deficiency
no central pallor
↑ MCHC: contain same absolute amount of Hb but smaller cell
↑ RDW
hereditary spherocytosis
complication of hereditary spherocytosis
aplastic crises due to parvovirus B19 infection (suppresses BM)
diagnostic test for hereditary spherocytosis
osmotic fragility test: put RBC in hypoosmotic solution → high % lysis of RBCs at any given concentration of NaCl (no normal spectrin)
treatment for hereditary spherocytosis
splenectomy: prevent removal of RBCs
post-splenectomy for hereditary spherocytosis
Howell Jolly Bodies: basophilic nuclear remnants in RBC (not removed by spleen)
Heinz bodies: oxidation of iron, denaturation of Hb
Bite cells: spleen remove Heinz bodies
G6PD deficiency
glycolytic enzyme deficiency → no ATP in RBC → can’t maintain Na/K ATPase → RBC swelling + hemolysis
pyruvate kinase deficiency
RBC missing surface markers: CD55 + CD59
complement attacks → lyses RBC
paroxysmal nocturnal hemoglobinuria
diagnostic test for PNH
Ham’s test:
add pH → activates complement → lysis of RBC
flow cytometry (used now)
HbS: glutamic acid → valine in ß chain at position 6 allows Hb to polymerize in RBC triggers of sickling = sickle crisis: hypoxemia dehydration acidosis 8% AA heterozygotes (HbS trait): resistant to malaria 0.2% AA homozygous
sickle cell disease
infant: asymptomatic (HbF)
infant + toddler: symptoms (HbF → HbS)
splenic sequestration crisis →↓ H/H, wedge-shaped infarcts on CT
autosplenectomy: complete infarction by 3-4 yo, ↑ risk infections by encapsulated organisms (vaccinate for meningococcus, pneumococcal, flu vaccine too)
aplastic crisis post-parvovirus B19
pain crises: vasoocclusion → ischemia
renal papillary necrosis due to hypoxemia in kidneys
sickle cell disease
osteomyelitis in sickle cell disease
salmonella
causes of aplastic crisis post-parvovirus B19
sickle cell disease
hereditary spherocytosis
types of pain crises: vasooclusion
dactylitis: painful hand swelling
acute chest syndrome
“hair-on-end” appearance from marrow hyperplasia (↑ RBC production)
sickle cell disease
ß thalassemias
treatment of sickle cell disease
hydroxyurea: ↑ production of HbF
definitive: BMT (stem cells without HbS mutation)
glutamic acid → lysine on ß globin chain on position 6
HbC form crystals in cell instead of long polymers in sickle cell disease
heterozygous for HbC: asymptomatic
homozygous for HbC: milder than sickle cell disease
SC disease = heterozygote with HbS + HbC mutation: milder than SCD
mild hemolysis, splenomegaly
hemoglobin C disease
RBC mechanically damaged as they pass through lumen of obstructed or narrowed vessel → RBC sheared by fibrin strand or shear force of HTN: DIC TTP/HUS lupus malignant HTN
microangiopathic anemia
shistocytes
microangiopathic anemia or macroangiopathic anemia
damage to RBC by prosthetic heart valve, aortic stenosis
macroangiopathic anemia
RBC infection → hemolysis
malaria
babesiosis
autoantibodies bind to RBC → hemolysis
either warm or cold agglutinins
autoimmune hemolytic anemia
IgG antibodies attach to RBC antigen at BODY TEMP → RBC agglutination (clump together) → chronic anemia EBV/HIV lupus CLL, non-hodgkin lymphoma congenital immune abnormalities drugs
warm agglutinins in autoimmune hemolytic anemia
IgM antibodies attach to RBC antigen ONLY IN COLD→ complement fixation → MAC lysis (and opsonization → phagocytosis) → acute anemia
EBV infection
Mycoplasma infection
CLL
cold agglutinins in autoimmune hemolytic anemia
most autoimmune hemolytic anemias have a positive
+ coombs test: RBC agglutination with addition of anti-human antibody because RBCs are coated with Ig or complement proteins (C3)
prepared Abs (coombs reagant) are added to a patient’s washed RBCs to detect the PRESENCE of Igs ALREADY on RBC (using antibody to detect an antibody) → RBCs agglutinate
direct coombs test
+ direct coombs test
hemolytic disease of newborn
drug-induced autoimmune hemolytic anemia
hemolytic transfusion reactions
patient’s SERUM incubated with normal RBC to detect for presence of ABs in serum → if Abs bind to RBCs →
RBCs agglutinate when anti-Ig antibodies (coombs reagant) added
indirect coombs test
+ indirect coombs test
Abs to foreign RBCs/blood are present:
test blood prior to transfusion (type and screen: donor blood screened for Abs)
screen for maternal Abs to a fetus’s blood
anemia jaundice: extravascular hemolysis in spleen pigmented gallstones: ↑ bilirubin splenomegaly spherocytes \+ osmotic fragility test
hereditary spherocytosis
