Red Blood Cell Disorders

Question 1

Why does microcytic anemia occur? What are some common causes of microcytic anemia?

Answer 1

It occurs because there is a reduced production of Hgb. The cells become small in order to maintain the appropriate concentration of Hgb. Examples of microcytic anemias include iron deficiency, thalassemia, anemia of chronic disease, sideroblastic anemia, and lead poisoning.

Question 2

What are some clinical symptoms of iron deficiency?

Answer 2

Koiloncoya, pica, and anemia.

Question 3

What labs do you expect in iron deficiency anemia?

Answer 3

Low ferritin, high TIBC, low serum iron, and low percent saturation. Expect to see microcytic hypochromic RBCs with increased RDW.

Question 4

Where does iron absorption occur?

Answer 4

In the duodenum via the DMT1 transporter

Question 5

How does anemia of chronic disease occur?

Answer 5

Chronic inflammation causes increased hepcidin. Hepcidin prevents the release of iron into the circulation.

Question 6

What labs would you expect in ACD?

Answer 6

High ferritin, low TIBC, low serum iron, low % saturation, and high free erythrocyte protoporphyrin

Question 7

How does sideroblastic anemia occur?

Answer 7

It occurs due to lack of protoporphyrin synthesis (an enzyme defect in ALAS). It can also be caused by alcoholism, lead poisoning, and vitamin B6 deficiency.

Question 8

What labs would you expect in sideroblastic anemia?

Answer 8

High ferritin, low TIBC, high serum iron, high % saturation

Question 9

What do you expect to see on histology for sideroblastic anemia?

Answer 9

Pappenheimer bodies, which are irregular dark blue granules in RBCs.

Question 10

What type of gene deletions can occur in alpha thalassemia, and what clinical findings are they associated with?

Answer 10

1 gene deletion: mild anemia

2 gene deletion: mild anemia (a cis deletion has common risk of severe thalassemia in offspring, while a trans deletion is when one deletion occurs on each chromosome)

3 gene deletion: see HbH on gel electrophoresis

4 gene deletions: not compatible with life –> hydrops fetalis

Question 11

Describe what you would expect to see in beta thalaseemia minor.

Answer 11

Expect increased HbA2 on gel electrophoresis; B/B+ is associated with mild anemia.

Question 12

Describe what you would expect to see in beta thalassemia major.

Answer 12

Expect HbA2. It is associated with a risk of aplastic crisis with parvovirus 19

Question 13

What causes a macrocytic anemia? What are some common causes of macrocytic anemia?

Answer 13

It occurs due to a messed up DNA synthesis, which makes large cells. Some examples include megaloblastic anemia (B12/folate deficiency), marked reticulocytosis, sulfa drugs, and AZT.

Question 14

What are some clinical findings you would expect with vitamin B12 deficiency?

Answer 14

A negative Schilling test, memory/neurological changes, and lemon yellow skin color. Expect increased MMA and homocysteine.

Question 15

What are some clinical findings you would expect with folate deficiency?

Answer 15

Expect the same as B12, but without neurological abnormalities. Folate is absorbed in the jejunum.

Question 16

What are some common normocytic anemias?

Answer 16

Hereditary spherocytosis, sickle cell anemia, paroxysmal nocturnal hemoglobinuria,, G6PD deficiency, and immune hemolytic anemias (includes PNH), microangiopathic hemolytic anemias (TTP-HUS, DIC), malaria, and aplastic anemia.

Question 17

What is hereditary spherocytosis?

Answer 17

It is formation of RBCs that look like spherocytes (no central pallor) due to a defect in spectrin.

Question 18

What test detects presence of hereditary spherocytosis?

Answer 18

Osmolality fragility test with a negative direct Coombs test

Question 19

Treatment for hereditary spherocytosis?

Answer 19

Splenectomy

Question 20

What characteristic cell pattern is associated with G6PD deficiency?

Answer 20

“Bite” cells due to removal of Heinz bodies. Avoid fava beans.

Question 21

What inheritance pattern does G6PD show?

Answer 21

It shows X-linked patterns, so in males.

Question 22

What change occurs in sickle cell disease?

Answer 22

An HbS mutation that results in a change of glutamic acid –> valine occurs.

Question 23

What clinical concerns could you expect to see in SCD?

Answer 23

Aplastic crisis from parvovirus B19, autosplenomegaly, salmonella osteomyelitis, and chronic leg ulcers.

Question 24

How do you treat SCD?

Answer 24

Give hydroxyurea to increase HbF.

Question 25

What are the two types of autoimmune hemolytic anemias?

Answer 25

Warm IgG disease and Cold IgM disease

Question 26

What conditions are associated with Warm IgG disease? What test would you use to detect this condition?

Answer 26

Associated with lymphomas/leukemias (SLE, Hodgkins, NHL)

Expect a positive Coombs test

Question 27

What conditions are associated with Cold IgM disease?

Answer 27

Includes PNH. Acute is associated with I blood group antigen (M. pneumoniae), while chronic is associated with I blood group antibody (Raynaud’s syndrome)

Question 28

What is the first line therapy for Warm IgG disease? For Cold IgM disease?

Answer 28

Warm IgG –> Corticosteroids and Rituxamab

Cold IgM –> Rituxamab

Question 29

What is hemolytic disease of the newborn? What treatment would you give?

Answer 29

It is maternal alloimmunization to fetal red cell antigens (D antigen of Rh group)

Mom is d, baby is D or Mom is Rh- while baby is Rh+

Give mom rhogam

Question 30

What is DIC (D-dimer)?

Answer 30

It is a condition that superconsumes platelet coagulation factors and occurs due to obstetric complications, gram negative sepsis, transfusion, malignancy, acute pancratitis, or nephrotic syndrome.

Question 31

What labs/HS would you expect in DIC?

Answer 31

high PTT, high PT, high fibrinogen, low platelets. Expect to see some schistocytes.

Question 32

What is TTP? What do you expect on HS?

Answer 32

Thrombotic thrombocytopenic purpura. It is characterized by hyaline microthrombi in small vessels. Expect helmet cells and schistocytes

Question 33

How can you distinguish DIC and TTP?

Answer 33

TTP will exhibit normal PT/PTT versus in DIC.

Question 34

How can you identify HUS?

Answer 34

It will occur due to E. coli O157: H7 and will probably be in a child.

Question 35

What is ITP? How can you distinguish how it presents in children versus adults?

Answer 35

in kids, the disorder is self-limiting. in adults, the disorder is chronic.

it is the immune creation of antiplatelet antibody with thrombocytopenia with increased megakaryocytes

Question 36

PLATELET DISORDERS: How can you distinguish Bernard-Soulier/vWD, Glanzmann’s, and other platelet storage disorders with chart shown on lecture?

Answer 36

In Bernard-Soulier/vWD you will see a lack of agglutination with ristocetin, but all other factors will exhibit agglutination.

In Glanzmann, you will see NO agglutination to anything.

In a platelet storage disorder, you will see agglutination to ADP, collagen, etc and a partial ristocetin agglutination.

Question 37

What HS do you expect to see in aplastic anemia?

Answer 37

Bone marrow that is hypocellular with fatty infiltration.