L4 RBC Disorders

Question 1

Young healthy subject can tolerate loss of _____mL

What percent of blood

Answer 1

500-1000mL

15-20% of blood

Question 2

Amount of blood loss and symptoms

Answer 2

500-1000: fine
1000-1500: light headed
1500-2000: thirst, short breath, sweating..
2000-25000: Shock

Question 3

Hemolytic anemia

Answer 3

Decreased RBC survival

Increased retention of RBC products (iron)

Question 4

Key feature of hemolysis

Answer 4

Haptoglobin binds hemoglobin released from lysed RBCs.

Low serum haptoglobin levels indicate hemolysis

Question 5

Intravascular hemolysis

What happens

Answer 5

• RBC dies
• Hemoglobin released
• Haptoglobin binds hemogl
• Hemoglob exceeds available haptoglobin
• Hemoglob is peed out (iron lost)
• Hemo–>heme–>bilirubin
• Hyperbilirubinemai, jaundice

Question 6

Extravascular hemolysis
Where?
Effects

Answer 6

Reticuloendothelial system (Spleen, Liver)
Free hemoglobin not released into blood or urin.
Breakdown still causes hyperbilirubinemia and jaundice

Question 7

Hemolytic anemias
Intrinsic Defect
Extrinsic Defect

Answer 7

Intrinsic: hemoglobin production, membrane abnormality
-inherited
Extrinsic: antibody, mechanical trauma
-acquired

Question 8

Hereditary spherocytosis
Type of defect, type of hemolysis
What is it
What causes it

Answer 8

Intrinsic, membrane defect, Exrtravascular hemolysis
RBC are sequestered and destroyed by spleen
Deficiency in spectrin

Question 9

Hereditary spherocytosis
Type of inheritance
How to help it

Answer 9

Autosomal dominant

Remove spleen. Abnormal RBC production still taking place, but spleen not destroying them

Question 10

Sickle cell
Type of defect, type of hemolysis
What is it
% of blacks

Answer 10

Intrinsic, extravascular hemolysis
Hemoglobin gels under low O2 causing sickle shape
8% of blacks in US

Question 11

Sickle cell
Type of inheritance
Cause

Answer 11

Autosomal codominant

Valine for glutamic acid at 6 position in beta chain of globin

Question 12

Thalassemia
What is it
Type of defect, type of hemoysis
type of inheritance

Answer 12

Diminished or absent synthesis of Alpha or beta globin chains of hemoglobin
Intrinsic defect, Extravascular hemolysis
Autosomal codominant

Question 13

Thalassemia

Cause

Answer 13

whole or partial gene deletion
Mutation in sequence
mRNA instability

Question 14

Thalassemia
Signs
Who

Answer 14

Anemia
destruction of RBC precursers
Microcytosis
Basophilic RBCs
Mediterranean, African, SE Asian

Question 15

Glucose-6 phosphate dehydrogenase deficiency
Type of defect, type of hemolysis
Type of inheritance

Answer 15

Intrinsic defect
Extrinsic hemolysis
X linked

Question 16

Glucose-6 phosphate dehydrogenase deficiency

What is it

Answer 16

RBCs susceptible to oxidant injury.
oxidized hemoglobin attaches to RBC membrane, reducing flexibility.
Asymptomatic w/o oxidant

Question 17

Erythroblastosis fetalis
Type of defect
type of hemolysis

Answer 17

Extrinsic defect
Extravascular hemolysis
Hemolytic disease of newborn: blood group incompatbility between mother and fetus

Question 18

Erythroblastosis fetalis

How it happens

Answer 18

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

Question 19

Megaloplastic anemia

Answer 19

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

Question 20

Myelophthisic Anemia

Answer 20

Hematopoietic cells in marrow crowded out by tumor or fibrosis

Question 21

Secondary polycythemia
causes
Signs

Answer 21

Stimuli which increase EPO
Cyanotic heart disease
Pulmonary disease
high altitude
Increased EPO

Question 22

Primary polycythemia
Cause
Treatment
Signs

Answer 22

Non regulated proliferation of red cells.
Stem cell disorder
Phlebotomy
Normal or suppressed EPO

Question 23

Aplastic anemia caused by

Answer 23

acquire defect in stem cell production

suppression of stem cell by T lymphocytes

Question 24

polycythemia vera

Answer 24

non regulated proliferation of red cells and myeloid cells