Red Blood Cell Disorders 1

Question 1

average life span of the RBC:

Answer 1

120 days

Question 2

what is the difference between MCH (mean cell hemoglobin) and MCHC (mean cell hemoglobin concentration)?

Answer 2

MCH: average content of hemoglobin PER RBC
MCHC: average concentration of Hb in a given volume of packed RBC’s

Question 3

what is the significance of RDW?

Answer 3

RDW = Red cell Distribution Width

it is a coefficient of variation of RBC volume

Question 4

normal size of a RBC should be nearly the same size as _____

Answer 4

lymphocytes

Question 5

what diseases can cause microcytic hypo chromic anemias

Answer 5

• iron deficiency
• lead poisoning
• anemia of chronic disease
• thalassemia

Question 6

what disease can cause normochromic normocytic anemia?

Answer 6

• acute blood loss
• hemolytic anemia
• anemia of chronic disease

Question 7

what disease can cause normocytic macrocytic anemia?

Answer 7

• folate deficiency

- B12 deficiency

Question 8

lead poisoning can result in what type of anemia?

Answer 8

• microcytic hypochromic anemia

Question 9

what are two broad categories of causes of anemia?

Answer 9

• accelerated RBC loss or destruction

- impaired RBC production

Question 10

compare the anemia seen in acute vs chronic blood loss

Answer 10

acute: risk of hypovolemia and associated with compensatory rise of erythropoietin levelsl normochormic normocytic anemia
chronic: no risk of hypovolemia; associated with iron deficiency → microcytic hypochromic anemia

Question 11

what kind of anemia is associated with acute hemorrhage

Answer 11

normochromic normocytic

Question 12

what kind of anemia is associated with chronic blood loss?

Answer 12

microcytic hypochromic

Question 13

what are 3 mechanisms of intravascular hemolysis

Answer 13

• mechanical injury to RBC’s such as defective valves, thrombi or heat
• complement fixation of antibody coated RBC’s
• infections (intracellular parasites such as malaria or production of toxins such as clostridia)

Question 14

examples of extravascular hemolysis

Answer 14

• due to inc phagocytic destruction of RBC’s primarily in the spleen
• RBC’s less deformable: spherocytosis, sickle cell
• RBC”s are rendered foreign via antibody coating

Question 15

______ hemolysis is associated with splenomegaly

Answer 15

extravascular

Question 16

discuss the following plasma serum levels in hemolytic anemia: 
unconjugated bilirubin
LDH 
haptoglobin 
free hemoglobin level

Answer 16

↑ unconjugated bilirubin
↑ LDH
↓ or absent haptoglobin (binds free Hb so when most of them bind the Hb, the levels of haptoglobin will ↓)
↑ free hemoglobin level

Question 17

which type of hemolysis: intravascular. or extravascular has more bilirubin in the serum

Answer 17

extravascular. with intravascular, some of the bilirubin can be lost in the urine

Question 18

hemoglobinuria is seen in intra/extra vascular hemolysis

Answer 18

intravascular hemolysis due to the absence of haptoglobin

Question 19

compare the levels of haptoglobin between intra and extravascular hemolysis

Answer 19

intravascular: absent haptoglobin
extravascular: ↓ haptoglobin

Question 20

what an examples of intrinsic RBC defects leading to hemolytic anemia?

Answer 20

• membrane defect: hereditary spherocytosis
• enzyme defect: G6PD
• hemoglobin defect: sickle cell and thalassemia
• paroxysmal noturnal hemoglobinuria

Question 21

what mutated proteins are associated with hereditary spherocytosis?

Answer 21

• ankyrin
• band 3
• spectrin
• band 4.2

Question 22

intercurrent infections of ____________ with hereditary spherocytosis can induce aplastic or hemolytic crisis

Answer 22

parvovirus B19

Question 23

↑ or ↓ MCHC in patients with hereditary spherocytosis

Answer 23

↑

Question 24

________ are indicative of splenectomy

Answer 24

Howell - Jolly bodies

Question 25

what are two tests you can do to diagnose hereditary spherocytosis

Answer 25

• osmotic fragility test: spherocytes lyse prematurely when exposed to hypotonic salt solutions
• Coombs test: negative test is diagnostic of hereditary spherocytosis

Question 26

_______ form of glutathione is required to convert hydrogen peroxide to water via the enzyme __________

Answer 26

reduced; glutathione peroxidase

Question 27

in order to get more reduced glutathione, it requires the enzyme ________ and ______

Answer 27

glutathione reductase and NADPH

Question 28

“bite cells” are seen in ______

Answer 28

G6PD

Question 29

describe the steps to the formation of Heinz bodies in ______

Answer 29

G6PD;

oxidants will oxidate the SH groups on globing chains of Hb → precipitation of donation globins on RBC membrane

Question 30

when should a G6PD enzyme assay be done?

Answer 30

• three months after the hemolytic episode has resolved

dont do the assay during the acute hemolytic episode because it will produce false negative results