Hematology Flashcards
Where do hematologic stem cells originate from?
Mesoderm
Timeline of fetal hematopoiesis
Initially-secondary yolk sac
5/6 weeks to 22 weeks gestations : fetal liver
After 22 weeks: bone marrow
Fetal hemoglobin is made of
Two alpha chains and two gamma chains
Hemoglobin A is made of
Two alpha chains and two beta chains
Hemoglobin A2 is made of
Two alpha chains and two delta chains
Hemoglobin Barts is made of
Four gamma chains
Hemoglobin H is made of
Four beta chains
Alpha globin genes: how many and where located
Four genes on chromosome 16
Beta globin genes: how many and what chromosome
Two genes on chromosome 11
Mutation in sickle cell disease
Valine for glutamic acid at position six (on chromosome 11 in beta globulin gene)
Cause of hemoglobin E
Abnormal transcription message in the beta-globulin gene results in decreased production of beta chains; 26 GLU —> LYS
How much does 1% fetal hemoglobin represent on a Kleinauer-Betke
50 mL of fetal blood
How much RhoGam do you give
Number of vials = mL of fetal blood/15
(1 vial = 300 mcg)
How does Apt test work
Add NaOH to sample. Fetal hgb is resistant to alkaline denaturation so will be pink. Adult hemoglobin will be yellow-brown
Test for Fanconi Anemia
Test chromosomes with mitomycin C —> increased chromosomal breaks
How to calculate Mentzer index?
MCV/#RBC; >13.5 consistent with iron deficiency, <11.5 consistent with thalassemia major
Cause of hereditary spherocytosis
Defect in membrane proteins (spectrin, ankyrin, band 3, protein 4.2)
Test for hereditary spherocytosis
Osmotic fragility test
Inheritance of G6PD deficiency
X-linked recessive
What does glucose-6-phosphate dehydrogenase do?
Converts glucose-6-phosphate to Penrose phosphate in the hexose monophosphate shunt pathway (needed to make glucose); requires NADP (which goes to NADPH and is needed to maintain the antioxidants catalase and glutathione)
Inheritance of pyruvate kinase deficiency
Autosomal recessive
Calculation of blood volume exchanged for partial exchange transfusion
Blood volume exchanged= ((observed hamtocrit-desired hematocrit)/observed hematocrit)* infants blood volume (mL)
State of normal iron vs with methemoglobin
Normal is reduced or ferrous state (2+); methemoglobin is oxidized or ferric state (3+)
Inheritance pattern of TAR syndrome
Autosomal recessive
Inheritance pattern of amegakaryocyte thrombocytopenia
Suspected x-linked transmission; male:female = 2:3
Neonatal clotting factors compared to adult levels
Contact (11, 12, prekallekrein, and HMW kininogen) < 70%
Vitamin K dependent (2, 7, 9, 10) <70% of adult levels
5, 8, 13, vWF, fibrinogen > 70%
ATIII, protein C, protein S: 30%
Thrombomodulin: 3x greater
Most common hemophilia and its inheritance
Hemophilia A (factor VIII deficiency); c-linked recessive
Inheritance pattern of hemophilia B
X-linked recessive (factor IX deficiency)
Inheritance pattern of factor XI deficiency
Autosomal recessive (also associated with Noonan syndrome) No degree of correlation between level of deficiency and symptoms unlike hemophilia A and B)
Inheritance of factor 13 deficiency
Autosomal recessive; has normal routine clotting studies
Calculation for the volume of red blood cells to transfuse in a neonate with acute hemorrhage
Desired increase in hematocrit x 1.6 x weight
Normal coagulation profile and infants with vitamin K deficient bleeding
Normal platelet count, increased PT, normal PTT (PTT can become increased with prolonged vitamin K deficiency)
Typical blood volume for:
Term infant
Preterm infant
SGA infant
85 mL/kg
100 mL/kg
105 mL/kg
Neonate to present with HLH before a month of age frequently having a mutation of the:
Perforin gene in chromosome 10q22.1
Areas of the brain, most frequently affected by hyperbilirubinemia
Globus pallidus and subthalamic nucleus
MCHC / MCV in spherocytosis
> 0.36
What is result if newborn screen shows: FA
Normal, no further action
What is result if newborn screen shows: FAS or FAC
Sickle cell carrier or Hemoglobin C carrier, family testing, and counseling
What is result if newborn screen shows: FS
Sickle cell anemia, sickle Beta0 thalassemia; start penicillin prophylaxis, refer to hematology, family testing and counseling
What is result if newborn screen shows: FSC
Sickle Cell Disease; start penicillin ppx, refer to heme, family testing and counseling
What is result if newborn screen shows: FSA
Sickle Beta+ Thalassemia; start penicillin ppx, heme referral, family testing and counseling
How is the Kleihauer Bette test done
Blood is treated with citric acid phosphate buffer, fetal cell stay red
What can give a false positive result on the Kleihauer-Betke
Anything that increases maternal hemoglobin F such as thalassemia, minor, sickle cell, or hereditary persistence of fetal hemoglobin
Anemia, short stature, triphalangeal thumbs
Diamond Blackfan anemia
Features of tar syndrome
Thrombocytopenia (from absent megakaryocytes), absent radius but normal thumbs, 30-35% cardiac (TOF or ASD), facial capillary hemangioma, eosinophilia and leukemias reactions
Clinical features of amegakaryocytic thrombocytopenia
Severe isolated thrombocytopenia, no other abnormalities, 50% develop aplastic anemia, risk of developing leukemia
