L2 - Pathology Of RBCs

Question 1

What is the MCV?

Answer 1

Mean corpuscular volume

Hct/RBC

Question 2

What is the MCH?

Answer 2

Mean corpuscular hemoglobin

Hgb/RBC

Question 3

What is the MCHC?

Answer 3

Mean corpuscular hemoglobin concentration

Hgb/Hct

Question 4

What does a low MCV indicate?

Answer 4

Microcytic anemia

Question 5

What does a high MCV indicate?

Answer 5

Macrocytic anemia

Question 6

What does a low MCH indicate?

Answer 6

Hypochromic anemia

Question 7

How do reticulocytes appear on a peripheral smear?

Answer 7

Polychromatic with a purple grey tinge in larger cells

Question 8

What is the RDW?

Answer 8

Red cell distribution width

Measure of variability in size of circulation erythrocytes

Question 9

Increased RDW can be seen in many conditions including what?

Answer 9

Iron deficiency anemia

Question 10

What are normal adult hemoglobins?

Answer 10

Hemoglobin A (97%) 
Hemoglobin A2 (2-3%)
Hemoglobin F (<1%)

Question 11

If you are heterozygous for S you have what?

Answer 11

Sickle cell trait

1 in 12 persons of African descent

Question 12

If you are homozygous for S you have what?

Answer 12

Sickle cell disease

Question 13

Populations with high incidence of HbS may have other variant hemoglobins such as?

Answer 13

HbC

Beta thalassemia

Question 14

What are the effects of chronic hemolysis?

Answer 14

Jaundice and gallstones

Anemia

Question 15

What are the effects of vascular occlusion?

Answer 15

Stroke, retinopathy, acute respiratory distress, acute chest syndrome, cor pulmonale, hepatic sequestration, hematuria and polyuria, autosplenectomy and infections, aseptic bone necrosis and osteomyelitis, placental failure in pregnancy, leg ulcers

Question 16

What are the effects of absence of all alpha globin genes?

Answer 16

Anemia and tissue hypoxia
Massively enlarged placenta leading to maternal complications, heart failure leading to large heart, pericardial effusion, edema, ascites and pleural effusion, congenital anomalies, large liver and spleen

Question 17

What is a direct antiglobulin test (DAT) (Coombs test)?

Answer 17

Detects the presence of Ab bound to the red cell surface

1. Autoimmune hemolytic anemia
2. Hemolytic disease of newborn
3. Transfusion reactions

Question 18

What is the indirect antiglobulin test (IAT)?

Answer 18

Detects abs in the plasma

1. Ab screen in pretransfusion testing
2. Screening in pregnancy for abs that may cause hemolytic disease of newborn

Question 19

What is warm hemolytic anemia?

Answer 19

IgG (most typical Ig subtype) binds stably at 37C
These opsonized cells are phagocytosed in the spleen or gradually lose membranes
Autoimmune or drugs

Question 20

What is cold hemolytic anemia?

Answer 20

IgM
Stronger affinity at low temps
More likely to manifest in nose and fingertips (Raynaud)
IgM leads to C3b deposition and the liver, spleen and bone marrow remove the cells

Question 21

What labs should be performed to evaluate vessel wall abnormalities?

Answer 21

Labs dont really help

Question 22

Which labs should be performed to evaluate reduced platelet numbers?

Answer 22

CBC for platelet count

Question 23

Which labs should be performed to evaluate defective platelet function?

Answer 23

Platelet function test, morphology

Question 24

Which test should be performed to evaluate clotting factor abnormalities?

Answer 24

PT and PTT

Question 25

What is the presentation of platelet disorders?

Answer 25

``` Superficial mucosal bleeding Petechiae Small superficial bruises Rare for hemarthroses Bleeding after minor cutes ```

Question 26

What is the presentation for coagulation disorders?

Answer 26

``` Deep soft tissue bleeding Minimal petechiae Large deep bruises Common hemarthroses Delayed bleeding after cuts ```

Question 27

Factor deficiencies or dysfunction will result in what?

Answer 27

Prolongation of aPTT and/or PT

Question 28

Describe SC disease

Answer 28

Milder than sickle cell disease Hb C can crystallize but doesn’t polymerize (although dehydration can result in polymerization) Same general complications and risks but less severe More likely to see Target cells than true sickle cells (poikilocytes)

Question 29

What are the stages of iron deficiency?

Answer 29

1. Reduced ferritin 2. Iron deficiency 3. Iron deficiency anemia

Question 30

Described the reduced ferritin stage of iron deficiency

Answer 30

Decreased serum ferritin <50-70 Decreased bone marrow iron Hb normal Sx start

Question 31

Describe the stage of iron deficiency

Answer 31

Decreased serum ferritin <30 Absent bone marrow iron Hb low/normal range Sx accelerate

Question 32

Describe the factor VIII-vWF complex

Answer 32

vWF carries Factor VIII to a platelet so that it can contribute to the clotting cascade vWF then goes and contributes to the repair of the endothelial defect