| How is blood count? | First investigation done (but overdone), three main components (RBC count (important to look at) and HB, Total |
| What are the roles of eosinophils and basophils? | Eosinophils against parasites, allergic responses.
Basophils unclear role |
| What are the roles of eosinophils and basophils? | Eosinophils against parasites, allergic responses.
Basophils unclear role |
| How are reticulocytes? | They are RBC nucleated, they carry alot of RNA and can be detected by supravital staining
live 2-3 days, 2% of RBCs, number of reticulocytes is useful in clinical test (increased ->marrow more active than normal, decreased ->production problem)
They come from pronormoblast, which gives normoblasts, that differentiate into reticulocyte which loses its nucleus to become RBC |
| How is blood composition? | Volume (70ml/kg), composed of cells circulating in plasma
55% plasma, 45% RBCs, <1% WBCs and platelets.
Serum is coagulated blood, plasma we added anti-coagulant like Ca citrate. |
| How is hemopoiesis occurring? | In bone marrow, stem cells give pluripotent stem cells, which divide into lymphoid progenitor and CFU-GEMM
Lymphoid progenitor gives T cells (IL12), B cells (IL6) and NK cells
CFU (colony forming unit)-GEMM (IL3) gives CFU-GM (gives monocyte and neutrophil ~ G-CSF [myeloid cell]), Basophil progenitor gives basophil, eosinophil progenitor gives eosinophil (IL5), Megakaryocyte progenitor gives megakaryocyte (TPO) and thus platelets, erythroid progenitor gives erythrocytes (EPO) |
| What are hemopoietic stem cells? | Rare subtype of cells in bone marrow, gives all blood cells, expresses CD34+, exists in stem cell niche of bone marrow, supported by cells surrounding, distributed in a range of conditions. |
| What are red cells? | 1,000 times more common than WBC, no nucleus live 120 days, carry oxygen to tissues, flexible shape allows migration through capillaries.
Regulated by EPO
Normal cells are 7 microns, highly flexible, biconcave shape
Contain hemoglobin, consists of 4 protein chains each w/ a pocket for heme, and 4 iron (heme) |
| What are lymphocytes? | Cells mediate immune function, can survive for many years and circulate around blood and through lymphoid tissues (so in blood transfusion it is important to irradiate the blood to not get and WBC to acceptor).
Two subtypes T and B cells
B cells make Ab, T cells regulate immunity, help B cells and can kill virally infected cells
95% are found w/in lymphoid tissue, enter through lymph nodes or high endothelial venules and leave nodes through lymphatic vessels into blood
Most are found in MALT (colon, tonsils, bronchus...) |
| What are neutrophils? | Play a role in bacterial and fungal infections, released from bone marrow and survive 2-3 days, ingest bacteria and cells that have been covered w/Ab, kill using toxic enzymes and oxygen radicals
They have multilobed nucleus, contain granules destroy bacteria, then undergo phagocytosis (PAMP recognition/Ab attachement/ Complement) |
| What are monocytes? | Cells migrate to tissues and become macrophages, ingest bacteria, play a role in triggering immune response
Help ingest pathogens, link innate immunity to adaptive |
| What are platelets? | Fragments of cytoplasm which bud off megakaryocytes in bone marrow, can stick to areas of damage w/in blood vessel and trigger formation of a blood clot. |
| How is bone marrow structure? | Almost all bones of children are hemopoietic bone marrow, in adults it is in vertebra and proximal long bones, stem cells are found in niche w/in bone marrow. |
| How is structure of spleen? | Areas of red pulp and white pulp, blood system has a unique open pattern not contained w/in capillaries.
Spleen has hemopoietic and immune functions |
| How are reticulocytes? | They are RBC nucleated, they carry alot of RNA and can be detected by supravital staining
live 2-3 days, 2% of RBCs, number of reticulocytes is useful in clinical test (increased ->marrow more active than normal, decreased ->production problem)
They come from pronormoblast, which gives normoblasts, that differentiate into reticulocyte which loses its nucleus to become RBC |
| How is the regulation of erythropoiesis? | By EPO, if the kidney detects hypoxia it releases EPO, which stimulates increased production of red cells.
Also EPO are elevated in people who live in high altitudes or who have lung disease (due to low O2) |
| How is O2 dissociation curve for Hb? | Hb releases O2 easier than myoglobin to allow tissue transfer of O2, at pO2 = 100mmhg SaO2=100% (arterial), 75% in 40 mmHg (venous).
2,3-DPG shifts dissociation curve to right as it increases, so does CO2 increase, H+ increase, and temperature increase |
| How is CO2 transport by Hb? | Carbonic anhydrase generates H2CO3 (carbonic acid) from CO2, which dissociates into bicarbonate and H+, where protons are buffered by Hb into HbH+ |
| What are the roles of eosinophils and basophils? | Eosinophils against parasites, allergic responses.
Basophils unclear role |
| How is hx in pt w/blood disorders? | Depends on clinical problem
RBC (anemia, fatigue, SoB), WBC (unusual prolonged infections, if excess lumps and swellings), platelets (bruising and bleeding) |
| How is examination of pt w/blood disorders? | Broad general exam, nails, skin mucus membranes may suggest anemia (glossy tongue = iron deficiency), lymph node exam may suggest leukemia/ lymphoma, bruising suggest platelet disorder. |
| How is blood count? | First investigation done (but overdone), three main components (RBC count (important to look at) and HB, WBC count, and platelet count)
Normal RBC (4-6 * 10^12), Hb (13.5-17.5 male and -2 for females), MCV (80-95 normal, less microcytic and more macrocytic)
White cells (normal 4-7 *10^9, decrease leukopenia, increase leukocytosis, may be lymphocyte or neutrophil alone)
Platelets (normal 150-400 * 10^9, low thrombocytopenia
seen in poor production and increased destruction and high cytosis increase risk of blood clot) |
| What is blood film? | Used to prepare for microscopic analysis for properly prepared smears, may be thin film or thick film (for malaria) |
| How is assessment of blood clotting done? | Two major tests, Activated partial thromboplastin time (APTT) and prothrombin time (PT)
test different components of clotting cascade |
| How is examination of bone marrow done? | We take a specimen of bone marrow and inspect it, may be aspiration or biopsy, usually done from pelvis (posterior iliac spine) or sternum (usually only aspiration not biopsy since very painful and risky)
We see cytosis of bone marrow and fat tissue, w/ age fat predominates and cytosis is decreased, important to know in order to see any disorder according to the age of presentation |
| What additional investigation techniques that may be used in hematology? | Genetic analysis (karyotype, WBC DNA, mutation analysis)
US (liver/ spleen for splenomegaly in cytosis for example)
CT , MRI (for brain and neuromuscular imaging no X ray use) PET (radiolabeled glucose taken up by tumor cells, see lymphoma tx) |
| What are red cell disoders? | Reduced number or Hb concentration (Anemia) body gets O2 deprived and SoB that is due to either decrease in production or increase in loss
Decreased production (by nutritional deficiency (B12, iron, folate), reduced erythroid cells by malignancy, ineffective red cell formation in case of thalassemia and chronic disease/ kidney problem)
Increase in red cells (polycythemia) causes problems like thick blood, increased risk of clot, may be natural response to hypoxia high EPO, but can occur due to clonal expansion of red cell precursors (polycythemia vera) EPO normal or low |
| How is size of red cell useful in dx of red cell disorder? | Microcytic hypochromic cells (MCV and MCH low, iron deficiency/ thalassemia)
Normocytic (acute blood loss, hemolysis, chronic disease, marrow infiltration)
Macrocytic (MCV high, megaloblastic anemia/ vitamin deficiency) |
| What are white cell disorders? | Deficiency (increases risk of infection) like neutropenia (caused by drugs/ infection, very risky if below 0.5)
Lymphopenia is rare from immune deficiency.
Increase in WBC more common, called leukemia, 4 major types: Acute leukemia (rapid) chronic (slow), lymphoid or myeloid
Tx specific for each type
Lymphoma (malignant WBC accumulate in lymphoid tissues not blood, may be hodgkins (Reed-Sternberg cells in biopsy/ non-hodgkins)
May be myeloproliferative disease (increased production) or myelodysplastic syndromes (active marrow dysfunctional cells)
Myeloma (malignant disease of plasma cells) |
| What are disorders of platelets? | Deficiency (thrombocytopenia) leads to bruising and bleeding, caused by autoimmune/ drugs
Increased (thrombocytosis) cause clots and bleeding
Sometimes function impaired (use of aspirin)
Deficiency in proteins of clotting can be inherited disorder or later in life (Hemophilia A deficiency in factor VIII most imp)
Acquired can be severe infection/ complication after birth.
Clot problems are more important than bleeding disorders (increased susceptibility for clotting) and risk increases w/bed rest/ surgery/ arrhythmia, so use of anti-thrombotics is very widely seen |
