1. Diseases of Hematopoietic and Lymphoid Systems

Question 1

two main causes of anemia

Answer 1

• reduction isn oxygen-carrying capacity of the blood
• reduction in total circulating red cell mass of RBCs

Question 2

pathogenesis of anemia:

Answer 2

• dec in tissue O2 –> erythropoietin secretion by RENAL CELLS –>
• compensatory hyperplasia of erythroid precursors in bone marrow (or extramedullary hematopoiesis)
• Immature cells into circulation (reticulocytosis)

Question 3

lab test for RBC morphology?

Answer 3

peripheral blood smear –> providing clues of underlying disorder

can perform automatic or manual differentials

Question 4

What features of RBCs can be determined from peripheral blood smear?

Answer 4

• size (normocytic, microcytic, macrocytic)
• shape
• Hb content (normochromic, hypochromic)

Question 5

what are the normal values for :

1. RBC
2. Hb
3. Hct

Answer 5

Question 6

what lab value do you look at for anemia?

what are the units and normal values?

Answer 6

Hemoglobin (g/dl)

Male - 16

Female 14

Question 7

You’ve determined pt has anemia using Hb. What other lab test helps determine type of anemia?

Answer 7

Mean cell volume

Question 8

What are the 3 categories of how to loose oxygen carrying capacity?

Answer 8

• bleeding
• hemolysis (RBC destruction)
• Diminished erythropoiesis (production)

Question 9

anemic pts typically present with pallor, fatigue, and lassitude (physical or mental weariness);

what signs may indicate a specific type of anemia?

Answer 9

• Hemolytic anemias –> may present with hyperbilirubinemia, jaundice, or pigmented gallstones
• Ineffective production –> iron overload

Question 10

What is ankyrin?

Which anemia is associated w/ a mutated form?

Answer 10

Ankyrin is a protein that connects spectrin meshwork to intrinsic membrane proteins –> decreased membrane stability –> loss of membrane –> RBCs become spherical

HEREDITARY SPHEROCYTOSIS

Question 11

which organ is affected most by hereditary spherocytosis?

Answer 11

Due to protein defect –> dec membrane stability –> loss of plasma membrane functionality –> RBCs become spheres –> spheres can’t transmit the spleen –> spherical RBCs are removed by macrophages –> causing SPLENOMEGALY

Question 12

this histo slide shows what hematopoietic disorder?

Answer 12

HEREDITARY SPHEROCYTOSIS:

spherical RBCs on smear;

we’re looking at splenic sinusoid;

If it’s spherical RBC and can’t get through splenic sinusoid –> can’t escape/ splenic MO thinks of them as abnormal and MOs destroy them –> hemolysis

Question 13

this histo slide shows what process that is defective in hereditary spherocytosis?

Answer 13

Shows RBCs trying to transiting through splenic sinusoid;

spherical RBCs can’t get through the membrane, so Macrophages destroy the,;

(If it’s spherical RBC and can’t get through splenic sinusoid –> can’t escape/ splenic MO thinks of them as abnormal and MOs destroy them –> hemolysis)

Question 14

what is the MOST PREVALENT hemoglobinopathy?

Answer 14

sickle cell anemia

Question 15

Structure of normal adult hemoglobinA?

Answer 15

2 alpha chains, 2 beta chains

Question 16

Which point mutation on which chain converts HbA –> HbS?

Answer 16

• Glutamic Acid –> Valine (hydrophobic)
• On #6 codon on Beta-chain

Question 17

A sickle cell crisis is pain that can begin suddenly and last several hours to several days. It happens when sickled red blood cells block small blood vessels that carry blood to your bones.

Which phenotype is this associated with?

Answer 17

Homozygotes (HbS)

8% of african americans in US are heterozygotes

Question 18

Sickling is influenced by other type of Hb present:

How does HbA, HbC, and HbF combine w/ HbS

Answer 18

Question 19

In which tissues is sickling increased?

Answer 19

In tissues with LOW OXYGEN;

E.G. spleen, bone marrow, areas of inflammation

Question 20

Histo image shows what disorder?

Answer 20

Sickle cell anemia;

you see the red, flat, abnormal red blood cells

Question 21

what does this post-splenectomy peripheral blood smear show?

Answer 21

intracellular and extracellular bacilli;

the pt had a lot of bacteria bc spleen wasn’t working properly

Question 22

What is HbH disease?

Answer 22

mild to moderate anemia, hepatosplenomegaly, and yellowing of the eyes and skin (jaundice)

Question 23

In which type of alpha-thalassemia does HbH disease most often occur?

Answer 23

When there is a loss of 3 ALLELES;

less damage than tetramers of alpha-chains –> so problem is less severe than thalassemia major –> HbH binds O2 tightly and doesn’t release it peripherally

Question 24

when and why does Thalassemia Major become apparent?

Answer 24

When HbF levels decline –> massive attempt by body to replace RBCS –>

• hepatosplenomegaly, expansion of BM –> skeletal deformities

Question 25

What can occur w/ treatment of Thalassemia Major?

Answer 25

Tx is with blood transfusions –> which can result in iron overload (hemochromatosis, which could be fatal);

if so, must tx w/ iron chelators or bone marrow transplant

Question 26

What normally functions to neutralize oxidants in RBCs?

Answer 26

Glutathione (GSH);

if not functioning –> deficiencies in enzymes that maintain adequate levels of GSH –> increase risk of oxidating/denaturing Hb –> denatured Hb precipitates

Question 27

difference b/w direct and indirect Coomb’s test?

Answer 27

• direct Coombs test is done on a sample of RBCsfrom the body.
• The indirect Coombs test is done on a sample of the serum (liquid part of the blood)

Question 28

what histo presentation is this?

pt from rural Mali w/ fever and malaise

Answer 28

Malaria –> hemolytic anemia