Red Blood Cell Disorders Flashcards
Why does microcytic anemia occur? What are some common causes of microcytic anemia?
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.
What are some clinical symptoms of iron deficiency?
Koiloncoya, pica, and anemia.
What labs do you expect in iron deficiency anemia?
Low ferritin, high TIBC, low serum iron, and low percent saturation. Expect to see microcytic hypochromic RBCs with increased RDW.
Where does iron absorption occur?
In the duodenum via the DMT1 transporter
How does anemia of chronic disease occur?
Chronic inflammation causes increased hepcidin. Hepcidin prevents the release of iron into the circulation.
What labs would you expect in ACD?
High ferritin, low TIBC, low serum iron, low % saturation, and high free erythrocyte protoporphyrin
How does sideroblastic anemia occur?
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.
What labs would you expect in sideroblastic anemia?
High ferritin, low TIBC, high serum iron, high % saturation
What do you expect to see on histology for sideroblastic anemia?
Pappenheimer bodies, which are irregular dark blue granules in RBCs.
What type of gene deletions can occur in alpha thalassemia, and what clinical findings are they associated with?
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
Describe what you would expect to see in beta thalaseemia minor.
Expect increased HbA2 on gel electrophoresis; B/B+ is associated with mild anemia.
Describe what you would expect to see in beta thalassemia major.
Expect HbA2. It is associated with a risk of aplastic crisis with parvovirus 19
What causes a macrocytic anemia? What are some common causes of macrocytic anemia?
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.
What are some clinical findings you would expect with vitamin B12 deficiency?
A negative Schilling test, memory/neurological changes, and lemon yellow skin color. Expect increased MMA and homocysteine.
What are some clinical findings you would expect with folate deficiency?
Expect the same as B12, but without neurological abnormalities. Folate is absorbed in the jejunum.
What are some common normocytic anemias?
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.
What is hereditary spherocytosis?
It is formation of RBCs that look like spherocytes (no central pallor) due to a defect in spectrin.
What test detects presence of hereditary spherocytosis?
Osmolality fragility test with a negative direct Coombs test
Treatment for hereditary spherocytosis?
Splenectomy
What characteristic cell pattern is associated with G6PD deficiency?
“Bite” cells due to removal of Heinz bodies. Avoid fava beans.
What inheritance pattern does G6PD show?
It shows X-linked patterns, so in males.
What change occurs in sickle cell disease?
An HbS mutation that results in a change of glutamic acid –> valine occurs.
What clinical concerns could you expect to see in SCD?
Aplastic crisis from parvovirus B19, autosplenomegaly, salmonella osteomyelitis, and chronic leg ulcers.
How do you treat SCD?
Give hydroxyurea to increase HbF.
What are the two types of autoimmune hemolytic anemias?
Warm IgG disease and Cold IgM disease
What conditions are associated with Warm IgG disease? What test would you use to detect this condition?
Associated with lymphomas/leukemias (SLE, Hodgkins, NHL)
Expect a positive Coombs test
What conditions are associated with Cold IgM disease?
Includes PNH. Acute is associated with I blood group antigen (M. pneumoniae), while chronic is associated with I blood group antibody (Raynaud’s syndrome)
What is the first line therapy for Warm IgG disease? For Cold IgM disease?
Warm IgG –> Corticosteroids and Rituxamab
Cold IgM –> Rituxamab
What is hemolytic disease of the newborn? What treatment would you give?
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
What is DIC (D-dimer)?
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.
What labs/HS would you expect in DIC?
high PTT, high PT, high fibrinogen, low platelets. Expect to see some schistocytes.
What is TTP? What do you expect on HS?
Thrombotic thrombocytopenic purpura. It is characterized by hyaline microthrombi in small vessels. Expect helmet cells and schistocytes
How can you distinguish DIC and TTP?
TTP will exhibit normal PT/PTT versus in DIC.
How can you identify HUS?
It will occur due to E. coli O157: H7 and will probably be in a child.
What is ITP? How can you distinguish how it presents in children versus adults?
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
PLATELET DISORDERS: How can you distinguish Bernard-Soulier/vWD, Glanzmann’s, and other platelet storage disorders with chart shown on lecture?
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.
What HS do you expect to see in aplastic anemia?
Bone marrow that is hypocellular with fatty infiltration.
