Hemolytic Anemias Flashcards
definition of hemolytic anemias
- a group of disorders characterized by decreased red cell lifespan
normal red cell lifespan
- 120 days
severity of anemia depends on
- ability of bone marrow to compensate
clinical features of hemolytic anemia
- jaundice
- dark urine
- pigmented gallstones
- chronic ankle ulcers
- splenomegaly
- requirement for folate
FAP DJS - He (hemolytic) a DJ who Faps
yellowing of sclera called
- scleral icterus
jaundice is
- more generalized yellow discoloration of tissues
what do you want to make sure to do before a splenectomy?
- vaccinate against encapsulated organisms
- spleen required to kill off encapsulated organisms
post-splenectomy blood findings
- Howell-jolly bodies
parvovirus B19 affect on blood cels
- infects and lyses and destroys RBCs in marrow
- causes 7-10 day halt to erythropoiesis
parvovirus B19 in patients with hemolytic anemias
- loss of red cell production causes reticulocyte count and hemoglobin to plummet dramatically
- aplastic crisis
hemolytic anemias classification schemes
- sites of red cell destruction
- acquired vs. congenital
- mechanism of red cell damage
sites of RBC destruction
- extravascular hemolysis
- intravascular hemolysis
extravascular hemolysis
- macrophages in spleen, liver, and marrow removed damaged or antibody-coated red cells
intravascular hemolysis
- red cells rupture within the vasculature, releasing free hemoglobin into the circulation
laboratory evidence for hemolysis
- evidence for increased RBC production
- evidence for increased RBC destruction
evidence for increased RBC production in the blood
- elevated reticulocyte count
evidence for increased RBC production in the bone marrow
- erythroid hyperplasia
evidence for increased RBC production in the bone
- deforming changes in the skull and long bones
- frontal bossing
erythroid hyperplasia
- reduced myeloid/erythroid ratio
- WAY more erythroids
frontal bossing caused by
- increased erythropoietic activity
- marrow space expansion
evidence for increased RBC destruction
- biochemical consequences of hemolysis
- morphological evidence of RBC damage
- reduced red cell lifespan
biochemical consequence of hemolysis in general
- elevated LDH levels
- elevated bilirubin
LDH levels high due to
- lysis of any cells
bilirubin is a byproduct of
- heme breakdown
when bilirubin is fractionated, the portion that is elevated is the
- unconjugated bilirubin
biochemical consequences of intravascular hemolysis
- reduced serum haptoglobin
most common hemolytic anemia due to membrane skeleton defects
- hereditary spherocytosis
hereditary spherocytosis defect in
- tethering proteins of membrane skeleton
- ankyrin
lipid microvesicles in heredity spherocytosis
- pinched off in the spleen
- causes decreased MCV
- and spherocytic change (spherocytes are engulfed by macrophages which causes the anemia)
hereditary spherocytosis genetic pattern
- autosomal dominant
hereditary spherocytosis patients with trivial infections will develop
- increased hemolysis
- abdominal pain
hereditary spherocytosis and MCHC
- MCHC will be elevated
- ONLY TIME WE CARE ABOUT THIS
hereditary spherocytosis diagnosed by
- osmotic fragility - lysis occurs at higher tonicities
hereditary spherocytosis and parvovirus B19
- causes aplastic crises
hereditary spherocytosis treatment
- folate supplementation
- splenectomy to resolve anemia
what cells remain after splenectomy in hereditary spherocytosis
- spherocytes because the cell will still bleb
what do RBCs require to maintain biconcave disc shape and hemoglobin in reduced form?
- constant energy
what happens if RBC don’t have energy
- they lyse
- or deform
two sources of energy for RBCs
- anaerobic glycolysis (Embden-Myerhof pathway)
- aerobic pathway (PPP - G-6-PD)
purpose of G-6-PD
- make NADPH and glutathione
role of NADPH and glutathione
- detox metabolites of oxidative stress
- elimination of methemoglobin
- glutathione neutralizes oxidative metabolites
- NADPH regenerates glutathione
in absence of adequate reducing ability, what will happen to hemoglobin
- will be converted to methemoglobin by oxidizing agents
- then denatured to precipitate as Heinz bodies
the spleen’s role on Heinz bodies
- leaves a bite cell or blister cell
G6PD deficiency genetic inheritance
- X-linked
things to avoid in G6PD deficiency
- oxidizing agents
examples of oxidizing agents to avoid
- anti-malarial (quinines)
- SULFA DRUGS
- dapsone
- vit K
- fava beans
- naphtha compounds (mothballs)
hemolysis in G6PD deficiency is often triggered by
- drugs or infections
African American patients G6PD levels immediately after a hemolytic episode
- may be normal since mature cells are lysed
- only younger cell with normal G6PD survive
G6PD deficiency symptoms
- jaundice
G6PD deficiency reticulocyte count
- elevated
G6PD deficiency bilirubin
- elevated
G6PD deficiency LDH
- elevated
G6PD deficiency haptoglobin
- low
G6PD deficiency seen on peripheral smear
- bite and blister cells
pathophysiology of acquired hemolytic anemias
- antibodies bind to red cell antigens
- lead to RBC destruction
acquired hemolytic anemias - IgG coated RBCs
- interact with Fc receptors on macrophages
- complete or partial phagocytosis
- spherocyte formation (extravascular hemolysis)
acquired hemolytic anemias - C3-coated red cells
- extravascular hemolysis
- complement mediated RBC lysis (intravascular hemolysis)
Immune hemolysis classifications
- autoimmune
- drug related
- PNH
two types of autoimmune hemolytic anemias
- warm antibody mediated
- cold antibody mediated
hallmark of autoimmune hemolytic anemia
- positive Coomb’s test
warm antibodies react with RBCs best at
- 37 degrees
- body temp
warm antibodies and agglutination of RBC
- do not agglutinate RBCs
warm antibody mostly composed of which antibody
- IgG
cold antibodies react best at
- below 32 degrees
cold antibodies and RBC agglutination - seen on peripheral blood smear
- cause RBC agglutination
- IgM is pentameric
cold antibodies composed mostly of which antibodies
- IgM which fix complement
Direct Coomb’s test tests for
- IgG or C3
- DIRECTLY ON RED CELLS
Coomb’s reagent contains
- anti-IgG and anti-C3 antibodies
- will cause agglutination
if Coomb’s test is positive
- EITHER IgG or C3 on red cells
- follow up with more specific test for anti-IgG or anti-C3
warm-antibody hemolytic anemias etiology
- primary or secondary to hematologic malignancy or another autoimmune disease
- induced by drugs
warm-antibody hemolytic anemias symptoms
- splenomegaly
- jaundice
- can be VERY symptomatic or not
warm-antibody hemolytic anemias - reticulocyte count
- elevated
warm-antibody hemolytic anemias - bilirubin
- elevated
warm-antibody hemolytic anemias - LDH
- elevated
warm-antibody hemolytic anemias - haptoglobin
- low
warm-antibody hemolytic anemias - diagnostic test
- positive Coomb’s test
warm-antibody hemolytic anemias - seen on peripheral smear
- spherocytes
treatment of warm-antibody hemolytic anemias
- may require transfusion
- immunosuppression is mainstay of therapy
first line of drugs for warm-antibody hemolytic anemias therapy
- corticostertoids
if steroids fail to work in warm-antibody hemolytic anemias
- splenectomy
- rituximab (CD20 - B cell)
distal problems with cold agglutinin disease
- distal ischemia
- red cell clumps cannot pass through microvasculature, leading to cyanosis and ischemia in extremities
cold agglutinin disease associated with these infections/diseases
- IGM SO ASSOCIATED WITH MMMMM
- mycoplasma pneumoniae
- mononucleosis
- lymphoproliferative diseases
cold agglutinin disease treatment
- keep patient warm
cold agglutinin disease steroids and splenectomy
- not effective
warm antibody hemolytic anemias pathophysiology
- IgG antibodies against RBC surface molecules are formed
- coat RBC with or without complement
- IgG coated fragment engulfed by macrophages
- spherocytes form
cold agglutinin disease pathophysiology
- IgM binds to red cells in cooler extremities
- fix complement
- lysed directly in vessel
- or engulfed by complement receptors on macrophages in liver
non-immune hemolytic anemias
- MAHA
- March Hemoglobinuria
- Infections
- Drugs, chemicals, and venoms