L4 RBC Disorders Flashcards
(24 cards)
Young healthy subject can tolerate loss of _____mL
What percent of blood
500-1000mL
15-20% of blood
Amount of blood loss and symptoms
500-1000: fine
1000-1500: light headed
1500-2000: thirst, short breath, sweating..
2000-25000: Shock
Hemolytic anemia
Decreased RBC survival
Increased retention of RBC products (iron)
Key feature of hemolysis
Haptoglobin binds hemoglobin released from lysed RBCs.
Low serum haptoglobin levels indicate hemolysis
Intravascular hemolysis
What happens
- RBC dies
- Hemoglobin released
- Haptoglobin binds hemogl
- Hemoglob exceeds available haptoglobin
- Hemoglob is peed out (iron lost)
- Hemo–>heme–>bilirubin
- Hyperbilirubinemai, jaundice
Extravascular hemolysis
Where?
Effects
Reticuloendothelial system (Spleen, Liver) Free hemoglobin not released into blood or urin. Breakdown still causes hyperbilirubinemia and jaundice
Hemolytic anemias
Intrinsic Defect
Extrinsic Defect
Intrinsic: hemoglobin production, membrane abnormality
-inherited
Extrinsic: antibody, mechanical trauma
-acquired
Hereditary spherocytosis
Type of defect, type of hemolysis
What is it
What causes it
Intrinsic, membrane defect, Exrtravascular hemolysis
RBC are sequestered and destroyed by spleen
Deficiency in spectrin
Hereditary spherocytosis
Type of inheritance
How to help it
Autosomal dominant
Remove spleen. Abnormal RBC production still taking place, but spleen not destroying them
Sickle cell
Type of defect, type of hemolysis
What is it
% of blacks
Intrinsic, extravascular hemolysis
Hemoglobin gels under low O2 causing sickle shape
8% of blacks in US
Sickle cell
Type of inheritance
Cause
Autosomal codominant
Valine for glutamic acid at 6 position in beta chain of globin
Thalassemia
What is it
Type of defect, type of hemoysis
type of inheritance
Diminished or absent synthesis of Alpha or beta globin chains of hemoglobin
Intrinsic defect, Extravascular hemolysis
Autosomal codominant
Thalassemia
Cause
whole or partial gene deletion
Mutation in sequence
mRNA instability
Thalassemia
Signs
Who
Anemia destruction of RBC precursers Microcytosis Basophilic RBCs Mediterranean, African, SE Asian
Glucose-6 phosphate dehydrogenase deficiency
Type of defect, type of hemolysis
Type of inheritance
Intrinsic defect
Extrinsic hemolysis
X linked
Glucose-6 phosphate dehydrogenase deficiency
What is it
RBCs susceptible to oxidant injury.
oxidized hemoglobin attaches to RBC membrane, reducing flexibility.
Asymptomatic w/o oxidant
Erythroblastosis fetalis
Type of defect
type of hemolysis
Extrinsic defect
Extravascular hemolysis
Hemolytic disease of newborn: blood group incompatbility between mother and fetus
Erythroblastosis fetalis
How it happens
During third trimester or during birth, the mother is exposed to fetus antigens
During next pregnancy, the mother makes antibodies to antigen that cross the placenta
Rh Antigen:
Rh negative mothers are given Anti-D Rhogam w/in 72 hr of deliver or Rh positive fetus
Removed Rh positive cells from mother
ABO antigen:
A and B babies born to O mothers
Megaloplastic anemia
B12 and folate deficiency Reduced Thymidine synthesis causing.. Decreased DNA synthesis causing.. Delayed mitotic division. Nuc increases, RNA synthesis stays the same leading to large megaloblast (RBC precurser), decreased mature RBC synthesis
Myelophthisic Anemia
Hematopoietic cells in marrow crowded out by tumor or fibrosis
Secondary polycythemia
causes
Signs
Stimuli which increase EPO Cyanotic heart disease Pulmonary disease high altitude Increased EPO
Primary polycythemia
Cause
Treatment
Signs
Non regulated proliferation of red cells.
Stem cell disorder
Phlebotomy
Normal or suppressed EPO
Aplastic anemia caused by
acquire defect in stem cell production
suppression of stem cell by T lymphocytes
polycythemia vera
non regulated proliferation of red cells and myeloid cells
