Hematology - intro Flashcards
Blood drive : name the main steps from user questionnaire to packed RBC ready to use in hospitals
- donor questionnaire
- testing of donor Hgb
- donor self exclusion question
- filtered as soon as returns to blood center to remove lymphocytes
- testes for multiple infectious disease
- Centrifuged to separate into Packed RBCs, platelets and plasma
What contains a PRBC (packed RBC)
- concentrated RBCs (plasma mostly removed)
- anti-coagulant and preservative
- hematocrit higher then in vivo blood
- shelf life 42 days
What contains fresh frozen plasma
- 1 unit/mL of all clotting factor including labile factor V and VII
- 400mg fibrinogen
- citrate as anticoagulant
where do platelets come from
from megakaryocytes in bone marrow
is there a nuclei in platelets?
no, anuclear cells
role of platelets
interact with proteins from coagulation cascade and lead to blood clotting
main function of RBC
carry oxygen
characteristics of RBC
- biconcave disks
- bags of Hb, few organelles
- anucleate
- outnumber white cells 1000:1
- contain the plasma membrane pritein spectrin and other proteins
- major factor contributing to blood viscosity
which form of Hb can unload oxygen to peripheral tissues
Oxygenated hemoglobin are in relaxed state
What is the oxygen dissociation curve
- At higher partial pressures of O2 (lungs) more Hgb is oxygenated
-At lower partial pressures of O2 (capillaries) Hgb less saturated so off loads oxyge
What is measured in a CBC
- white blood cells (neutrophils/lymphocytes, monocytes, eosinophils, basophils, blasts)
- Red blood cell count/Hb/RBC indices
- Platelet count
how to define anemia in a CBC
RBC number, hemoglobin or hematocrit below the normal range
what is hemoglobin
oxygen carrying protein in red blood cells. Two alpha chain and two beta chains. Four heme groupes which carry O2
Which hb chain is affected in sickle cell?
mutation in beta chain
Which hb chain is affected in thalassemia?
defect in production of alpha or beta
what is hematocrit
percentage of red blood cells in a known volume of blood
What is a reticulocytes
immature RBCs which still contain robosomal RNA. These normally circulate in the peropheral blood
What is MCV
Meac red blood cell volume: average size of red blood cells
2 types of abnormal MCV
microcytosis or macrocytosis
6 steps to normal herythropoiesis
- pronormoblast
- basophilic normoblast
- poly-chromatophilic normoblast
- ortho-chromatic normoblast
- reticulocyte
- red blood cells
steps 1 to 4 happen in the bone marrow and 5-6 in the blood
which hormone controls erythropoiesis ?
erythropoietin a hormone produced by the renal tubule cells which sense the O2 level in the blood
Systemic response to compensate anemia
- renal tubular cells increase the production of erythropoietin
- the bone marrow should increase RBC production
- The number of reticulocytes in the blood should increase
2 only options to explain anemia (general)
-upset in the balance of RBC production
- RBC destruction or loss
6 specific causes of anemia
- deficiency of building block for RBCs
- Congenital abnormality of the content of RBC
- Abnormality in the production site of RBC
- loss of RBC (bleesing)
- Decreased lifespan of red blood cells in the circulation (hemolysis)
- chronic illness: suppressed erythropoiesis
function of iron and where it is stored
part of the heme group, shich carries oxygen. stored in the form of ferritin
Role of B12 and Folate
B12 : vitamin essential for DNA synthesis
Folate: vitamin essential for DNA synthesis
what could explain abnormality in the production site of RBC
empty bone marrow (aplastic anemia), leukemia, pymphoma, cancer
kind of renal disease that could cause anemia
renal disease (cant secrete erythropoietin) or other diseases lead to cytokine and bone marrow suppression
where is thalassemia more common
Mediterranean and equatorial regions of Asia and Africa.
where is sickle cell anemia most common
african descent
G6Pd deficiency
african, mediterranean, asian descent
what can lead to b12 dificiency
vegetarian diet. and poor diet may lead to folate deficiency
signs of anemia
pallor, nails changes, tachycardia
one sign of rapid hemolysis
jaundice
What information does the reticulocytes count give?
The retic count give indirect information on the bone marrow’s ability to respond to anemia
if anemia and increased retic : bone marrow is functioning normally suggesting bleeding or hemolysis
if anemia and normal or decreased retic: abnormal erythropoiesis or bone marrow dysfunction
What can lead to megaloblastic anemia (macrocytosis, MCV > 95)
abnormality in DNA synthesis, vitamin b12 deficiency, folate deficiency, drugs (chemotherapy drugs)
what type of anemia presents with: low MCV, normal MCV, high MCV
other lab test that can be ordered to investigate anemia (other than CBC)
- Iron studies: ferritin, serum iron, %sat, liver function test, renal function test, thyroid function
- B12/folate levels
- hb electrophoresis
- bone marrow aspirate and biopsy
what means hemolysis
increased breakdown of red blood cells. An elevated reticulocyte count is often the first clue
Hemolysis refers to the breakdown of red blood cells (RBCs), and it can be classified based on the underlying cause of the RBC destruction. name 4
- extra-corpuscular
- red blood cell membrane
- hemoglobin
- enzyme defects
explain what extra-corpuscular hemolysis is
This term refers to causes of hemolysis that are related to external factors outside the RBC itself. Examples include mechanical destruction from artificial heart valves or shear stress in the bloodstream.
examples of red cell membrane defect that cause hemolysis
hereditarry elliptocytosis
hereditary spherocytosis
examples of hemoglobin defect that cause hemolysis
sickle cell, thalassemia
examples of enzyme defect defect that cause hemolysis
G6PD deficiency, pyruvate kinase deficiency
A 23 year old female presents to your office because of fatigue and palpitations. You note pallor and koilonychia on physical exam:
Laboratory: WBC 6.5 x 109/L
Hgb 107 g/L (120-160 g/L)
MCV 78 fl (80-95 fl)
Plt 450 x 109/L
Microcytic anemia
differential for microcytic anemia
iron deficiency, thalassemia, chronic disease
An 81 year old gentleman is referred for investigation of anemia prior to heart surgery: you note mild jaundice and a palpable spleen on examination
Laboratory: WBC 6.5 x 109/L
Hgb 85 g/L (120-160 g/L)
MCV 102 fl (80-95 fl)
Plt 350 x 109/L
Macrocytic anemia
diffential for macrocytic anemia
Megalloblastic Vit B12 def
Folate def
Drugs
Myelodysplastic Non-megalloblastic: Reticulocytosis
Liver disease
Thyroid disease
