35 - Haematology Intro Flashcards
Types of haemopoietic stem cell self-renewal
Symmetric
Asymmetric
Lack of self-renewal x2
Symmetric self-renewal
Increases stem cell pool
No differentiated progeny
Asymmetric self-renewal
Maintain stem cell pool
Generation of differentiated progeny
Lack of self-renewal
No stem cell pool
Either generation of differentiated progeny or nothing at all
Haemopoietic lineages
Myeloid - granulocytes (WBC), erythrocytes (RBCs), platelets
Lymphoid - B-lymphocytes, T-lymphocytes
Colony-forming unit (CFU-GEMM)
Myeloid lineage
Colony-forming unit (CFU-L)
Lymphoid lineage
Staging of haemopoiesis
- Multipotential stem
- Pluripotential stem
- Committed stem
- mature cells
Embryology of haemopoiesis
Trophoblast
Starts day 27 in the aorta gonad mesonephros region
Expands rapidly at day 35 and gone by 40
Due to migration to liver
Polycythaemia means
Raised RBC count
Relative polycythaemia
Raised RBC count when plasma volume reduced
Granulocytes - what do they have? who are they?
neutro/eosino/basophils
have cytoplasmic granules
Neutrophils - features
Phagocytes
Most common
10x10^9/l
Live for only a few hours
Causes of neutrophilia
High #
Bacterial infection
Inflammation
Causes of neutropenia
Low #
Side affect of drug
Eosinophilia causes
Parasitic infection
Allergies
Basophils
Rare cells - part of primitive immune system
Causes of basophilia
Chronic myeloid leukaemia
Monocyte features
Phagocytic and APCs
Migrate to tissues and are identified as ‘macrophages’ or ‘histiocytes’
Kupffer cells in liver
Langerhans cells in skin
High # of monocytes = monocytosis - causes
Tuberculosis
Lymphocyte types
NK cells
B-lymphocytes
T-lymphocytes
Plasma cells
NK cells
Innate immune system
Large granular lymphocytes which recognise non-self cells
B - lymphocytes
Adaptive immune system
Rearrange the immunoglobuin genes to enable antigen specific Ig production
Humoral immunity
T-lymphocytes
Adaptive immune system
Rearrange the T-cell antigen receptors
Cell-mediated immunity
Target specific cytotoxicity
Interact with B cells, macrophages
Regulate immune responses
Lymphocytosis causes
high #
Atypical lymphocytes of glandular fever (infectious mononucleosis)
Chronic lymphocytic leukaemia
Lymphopenia causes
Post bone marrow transplant
Plasmacytosis causes
Infection
Myeloma
Platelets - features
Derived from bone marrow megakaryocytes
200x10^9/l
W/ soluble plasma clotting factor + endothelial cells form part of clotting system
What are haematologists responsible for?
Labs
Patients
Advice
What are non-haematologists responsible for?
Blood count + coag tests
Transfusion
Haematological disease can present anywhere…
Diagnostic tests:
FBC
Blood film aka smear
Coagulation screen
What does FBC test?
[Hb]
Red cell parameters inc. mean cell volume (MCV) and mean cell Hb (MCH)
White cell count
Platelet count
Coagulation screen what is it?
Test measure the time taken for a clot to form when plasma is mixed with reactive agents
What parts of coagulation cascade can be assayed?
Prothrombin time
Activated partial thromboplastin time
Thrombin time
Sensitivity definition
The proportion of abnormal results correctly classified by the test
The ability to detect a true abnormality
Specificity defintion
Defined as the proportion of normal results correctly classified by the test
The ability to exclude an abnormal result in a healthy person
Equation for sensitivity
TP / (TP + FN)
True positive / (TP + false negative)
Equation for specificity
TN / (TN + FP)
Types of anaemia
Microcytic hypochromic
Normocytic normochromic
Macrocytic
Microcytic hypochromic anaemia test readings
MCV
Microcytic hypochromia is a sign of…
Iron deficiency Thalassaemia Anaemia of chronic disease Lead poisoning Sideroblastic anaemia
Normocytic normochromic test readings
MCV 80-95 fl
MCH ≥ 27 pg
Normocytic normochromic is a sign of…
Many haemolytic anaemias Anaemia of chronic disease After acute blood loss Renal disease Mixed deficiencies Bone marrow failure (post-chemo or due to cancer)
Macrocytic anaemia test readings
MCV >95fl
Macrocytic anaemia is a sign of…
Vit B12 or folate deficiency
Non-megaloblastic: alcohol, liver disease, myelodysplasia, aplastic anaemia
Description of iron deficiency
Small, pale red cells (low MCV and MCH)
Variable size and shape
Long thin ‘pencil’ cells
Description of vit B12
Hypersegment neutrophils and oval macrocytes
