Intro to Haematology Flashcards
What is covered by the clinical speciality of heamtology?
1 - Investigation of blood and bone marrow
2 - Management of disorders of blood and bone marrow
What are the 3 major constituents of blood?
1 - Plasma
2 - Buffy coat
3 - Red blood cells
What are the components of plasma?
1 - Clotting/coagulation factors
2 - Albumin
3 - Antibodies
What are the components of the buffy coat?
1 - Platelets
2 - White cells or Leucocytes
What are the 3 main functions of blood?
1 - Transport
2 - Maintenance of vascular integrity
3 - Protection against pathogens
What does blood transport?
1 - Gases (O2, CO2)
2 - Nutrients
3 - Waste
4 - Messages
What component of blood carries gases?
Red cells
What component of blood carries the nutrients, waste and messages?
Plasma
In what ways does blood maintain vascular integrity?
1 - Prevention of leaks
2 - Prevention of blocakges
Which components of blood are responsible for preventing leaks?
1 - Platelets
2 - Clotting factors
Which component of blood is responsible for preventing blockages?
1 - Anticoagulants
2 - Fibrinolytics
In what ways does blood provide protection from pathogens?
1 - Phagocytosis and killing
2 - Antigen recognition and antibody formation
Which components of blood are responsible for phagocytosis and killing?
Macrophages
Neutrophils
Which components of blood are responsible for anitgen recognition and antibody formation?
Lymphocytes
What are the main categories of haematological abnormalities?
1 - High levels of blood
2 - Low levels of blood
3 - Altered function
What is haematopoiesis?
The differentiation of stem cells into red blood cells and lymphoid cells
What are erythrocytes?
Red blood cells (erythros = red)
What are the myeloid cells?
Erythrocytes
Platelets
Neutrophils
Monocytes
Basophils
Eosinophils
What are the lymphoid cells?
Natural Killer cells
T and B cells
What is meant by totipotency?
The ability of a single cell to divide and produce all of the differntiated cells of an organism
Can stem cells self-renew?
Yes
What type of marrow do stem cells contain?
Marrow niche - CXCR4
What are the processes involved in stem cell differentiation?
Binary Fission
Flux
What regulates the process of flux?
Hormones
Growth factors
Where is bone marrow found in children?
In most bones
Where is bone marrow found in the elderly?
Axial bones
What does bone marrow look like?
Stroma and sinusoids
What are the stages in Erythroid differentiation?
1) Erythroblast
2) Reticulocyte
3) Erythrocyte
What is erythropoietin?
Glycoprotein cytokine
What does erythropoietin do?
Stimulates the production of RBC’s in bone marrow
Where is erythropoietin made?
Kidney
In response to what conditions is erythropoietin made?
Hypoxia
Why is the reticulocyte count useful?
It can be used as a measure of red cell production
What is polycythaemia?
An abnormally high concentration of haemoglobin in the blood
What are the causes of polycythaemia?
Reduction in plasma volume
Increased in number of red blood cells
What is the general consequence of anaemia?
Poor gas transfer
What are the specific problems caused by anaemia?
Dyspnoea
Fatigue
What are the general causes of anaemia?
1 - Decreased production
2 - Increased loss
In general, what is anaemia?
Decrease in amount of RBC’s or Haemaglobin
What can be the reason for anaemia caused by deficiency in haematinics?
- Iron
- Folate
- Vitamin B12
What is meant by the term ‘haematinics’?
The vitamins and minerals required for the proper creation of RBC’s
What are the congential causes of anaemia?
Thalassaemias
What is Thalassaemias?
Genetic problem resulting in production of not enough haemaglobin
What can be the reasons for anaemia resulting from ‘increased loss’ of blood?
Bleeding
Haemolysis
What is haemolysis?
The break down of RBC’s
What are some common diseases of RBC’s?
Microcytes
Macrocytes
Sickle cell
What are microcytes and with what condition are they associated?
Very small RBC’s associated with anaemia (e.g. iron deficiency)
What are macrocytes and with what condition are they associated?
Large RBC’s associated Folate deficiency
What are Burr cells and with what condition are they associated?
RBC with spiky outer membrane associated with Renal failure
What are schistocytes and with what condition are they associated?
Fragments of RBC’s associated with haemolytic uraemic syndrome
What are sickle cells and with what condition are they associated?
They have a sickle shape, have problems carrying haemoglobin and are associated with sickle-cell disease
What is the function of platelets?
To ‘clump’ together during bleeding in order to form a clot
Which hormone is responsible for the production of platelets?
Thrombopoietin
Where is thrombopoietin produced?
Liver
What is the lifespan of a platelet?
7 days
In what diseases are problems with platelets a feature?
Thrombocytosis (too many platelets)
Thrombocytopenia (not enough platelets)
What medication can affect the functioning of platelets?
Aspirin (fever, pain or inflammation medication)
Clopidogrel (antiplatelet medication)
What is the function of neutrophils?
To ingest and destroy pathogens
Especially bacteria and fungi
What are the different white cell types?
Neutrophil
Eosinophil
Basophil
Monocytes
Lymphocytes
From which cells are macrophages derived?
Monocytes
How do neutrophils compare to macrophages?
Neutrophils - granulocytes which work only in the circulation
Macrophages - agranulocytes which work within tissue
How long do neutrophils take to respond to them being required?
A few hours
What are the steps of differentiation of neutrophils?
1 - Blast
2 - Promyelocyte
3 - Myelocyte
4 - Metamyelocyte
5 - Neutrophil
What hormone stimulates bone marrow to produce neutrophils?
Granulocyte - colon stimulating factor (G-CSF)
What do neutrophils mostly fight against?
Infection
Inflammation
In what conditions can G-CSF be used therapeutically?
Neutropenia (not enough neutrophils)
What can cause neutropenia by decreased production of neutrophils?
1 - Drugs
2 - Marrow failure
What can cause neutropenia by increased consumption of neutrophils?
1 - Sepsis
2 - Autoimmune
What is the function of monocytes?
To ingest and destroy pathogens
What is the function of eosinophils?
Fight off:
1 - Parasites
2 - Allergies
What is the function of lymphocytes?
Cells of the immune system
What is lymphocytosis and with what conditions is it associated?
An increased number of lymphocytes
Associated with:
- Infectious mononucleosis
- Pertussis
What is lymphopenia and with what conditions is it associated?
Not enough lymphocytes:
- Usually post-viral
- Lymphoma
What are the subtypes of lymphocytes?
B cells
T cells
NK cells
What is the function of B cells?
Make antibodies
What is the function of T cells?
Helpers - Help other WBC’s with immunity
Cytotoxic - Destroy virus infected cells
Regulatory - Maintain immunity
Where are B cells produced?
Bone marrow
Where are T cells produced?
Thymus
What antigen is responsible for regulating the immune system?
Human Leukocyte Antigen
How does Human leukocyte antigen work?
It identifies whether cells are infected or not - if they are infected then an immune response is triggered
What blood disorders are associated with disease of the liver?
Anaemia
Deficient clotting factors
What blood disorders are associated with kidney disease?
Haemolytic uraemic syndrome
Anaemia
What blood disorder is associated with the GI system?
Anaemia
What blood disorder is associasted with the respiratory system?
Polycythaemia
What is the most common inherited bleeding disorder?
Von Willebrand disease
What is the most common congenital coagulation factor deficiency?
Haemophilia A
What are the normal haemoglobin values for a male < 70 y.o.?
135-170
What are the normal haemoglobin values for a female < 70 y.o.?
120-160
What is the normal range for platelet count?
150-400 10^9/L
What is the normal range for white blood cells on a full blood count?
4-10 10^9/L
What are the diagnostic tools used in blood disorders?
1 - Full blood count
2 - Clotting times
3 - Check Iron, B12 and Folate levels
4 - Bone marrow aspirate
5 - Lymph node biopsy
6 - Imaging
What are the main categories of treatment for blood disorders?
1) Replacement
2) Transplantation
3) Drugs
What are the major causes of splenomegaly?
1 - Infectious (e.g. Epstein-Barr virus, TB)
2 - Haematological Malignancy (e.g. leukemias)
3 - Portal hypertension
4 - Haemolytic disorders (e.g. spherocytosis)
5 - Connective tissue disorders (e.g. SLE)