Haematology Flashcards
What is hct (haematocrit)?
Percentage volume of blood that is red blood cells.
What is RBC (Red blood cell count)?
Number of red blood cells in a given volume of blood.
What is Hb?
Haemoglobin concentration.
What is MCV?
Average number of red blood cells in volume of blood.
What is MCH?
Average amount of haemoglobin in each red blood cell.
What is MCHC?
Average amount of haemoglobin compared to size of the cell.
What is anaemia?
Anaemia is a reduction in the amount of haemoglobin
in a given volume of blood
What are the two mechanisms that drive anaemia?
RBC failure of production or RBC excess loss/destruction
If microcytic anaemia is present what colour are the red blood cells?
Hypochromic (pale).
If macrocytic anaemia is present what colour are the red blood cells?
Normochromic (normal).
What proportion of normal red blood cells are pale?
A third of the diameter.
Why is the centre of the red blood cell pale?
Red blood cell have a disc shape. The centre has less haemoglobin and therefore is paler.
Why are hypo-chromic cells pale?
Less haemoglobin and flatter cell.
What are the three causes of iron deficiency anaemia?
Increased loss (blood loss), insufficient intake, increased requirement.
What are common causes of a loss of iron?
Hookworm, gastrointestinal bleeding, heavy menstrual bleeding.
What are common causes of an insufficient intake of iron?
Vegetarian diet, Coeliac disease (malabsorption).
What are common causes of an increased requirement of iron?
Pregnancy and infancy.
What are symptoms of iron deficiency anaemia?
Fatigue, Shortness of breath.
Why are iron deficiency anaemia symptoms caused?
Low amounts of haemoglobin means less oxygen to tissues. Reduced rate of respiration causes fatigue.
What should iron deficiency show in the blood test?
Increased transferrin and reduced serum ferritin.
What do iron deficiency anaemia and thalassaemia trait cause?
Micryocytic red cells.
How can you differentiate iron deficiency anaemia and thalassaemia trait?
Electrophoresis of haemoglobin and iron studies.
What do you see in β
thalassemia electrophoresis and why?
Raised Haemoglobin A2 is found where there is a reduction in beta globin chains, caused by β
thalassemia (or trait). Allows more delta chains to be incorporated into hemoglobin and so raised HbA2.
Important markers of thalassaemia trait.
Raised RBC and normal mchc.
Why do people with anaemia from chronic disease not benefit from iron supplementation?
They have high amounts of iron storage. (high ferritin levels).
What causes a reduction in haem?
IRON DEFICIENCY
ANAEMIA OF INFLAMMATION/CHRONIC DISEASE
What caused a reduction in globin?
THALASSAEMIA
What happens to hepcidin in response to iron deficiency anaemia?
Downregulated.
What happens to hepcidin in response to anaemia of chronic disease?
Hepcidin is produced.
Explain the process of the absorption of vitamin b12?
B12 combines with Intrinsic factor (IF) made in the
gastric parietal cells. B12-IF binds to receptors in the ileum.
Deficiency in vitamin b12 can be caused by what?
inadequate intake (veganism), inadequate secretion of IF (pernicious anaemia), Malabsorption (coeliac disease), lack of acid in stomach.
Lack of vitamin B12 or folic acid causes what?
Megaloblastic anaemia.
What else can cause macrocytic anaemia?
Liver disease and ethanol toxicity.
What is haemolytic anaemia
Premature destruction of red blood cells.
Normal erythrocyte life span?
120 days.
An increased blue tinge to the
cytoplasm of a red cell is referred to as what?
Polychromasia.
What does polychromasia indicate?
A young red blood cell which tells us that there is an increase in erythropoiesis which is a response to haemolysis.
What are Reticulocytes?
Reticulocytes are newly produced, relatively immature red blood cells.
What does Reticulocytosis indicate?
Reticulocytosis may occur as a response to bleeding or
red cell destruction (haemolysis)
What will be raised in full blood count is patient has reticulocytosis?
Reticulocytes and MCV. Young red cells are about 20% larger than mature red cells so if there is an increased proportion of young red cells (polychromasia/reticulocytes) in the circulation, the average cell size (MCV) will be increased
What are the consequences of red blood cell sickling?
Haemolysis and vaso-occlusion.
What causes ‘sickling’ in sickle cell disease?
Polymerization of hemoglobin S that make red blood cells less flexible.
What causes symptoms of anaemia in patients with sickle cell disease?
HbS has a lower affinity for oxygen than HbA.
What is the spleen involved in?
- Immune defence
- Breakdown and removal of old, malformed or damaged red blood cells.
What causes the spleen to no longer work in sickle cell patients?
Repeated splenic vaso-occlusion.
What is it called when the spleen no longer works?
Functional hypospleenism.
What might you recommend to someone with hypospleenism?
Antibiotics. Might also recommend immunisations.
Why does polycythaemia happen?
Too little plasma. Blood becomes too thick.
What does polycythaemia increase the risk of?
Thrombosis.
What are raised in a patient with polycythaemia?
Hb, Hct and RBC.
What is infectious mononucleosis?
Swollen lymph glands, fever, sore throat. Resulting from Epstein‒Barr virus infection.
What is seen on the blood film of a patient with Infectious Mononucleosis?
Scalloped margins and ‘hugging’ of the surrounding red blood cells. Lymphocytes that have intensely basophilic (blue) cytoplasm.
What do we see on the blood film of a patient with CLL?
Smear cells. Lymphocytes.
What helps confirm diagnosis of CLL?
Flow cytometry. Profile of cell surface markers expressed by lymphocytes.
How can blast cells be recognised?
Large size, high nucleus/cytoplasmic ratio.
Why does the philadelphia chromosome leads to CML?
BCR::ABL1 gene on philadelphia chromosome encodes a protein with uncontrolled tyrosine kinase activity, which gives rise to leukaemic clone.
How can you treat CML?
Tyrosine kinase inhibitors. These block tyrosine kinase and so there is no signal for cell to divide.
CML key symptom?
Splenomegaly.
How do you differentiate acute lymphoblastic leukaemia and acute myeloid leukaemia on a blood film?
Cytoplasm in blasts of AML contain
granules. Very irregular shape of the nuclei seen in acute lymphoblastic leukaemia.
What is pancytopenia?
Deficiency of all three cellular components of the blood (red cells, white cells, and platelets).
What kind of cells do you see on blood film of acute myeloid leukaemia?
Myeloblasts, Nucleated red blood cell
What kind of cells do you see on blood film of chronic myeloid leukaemia?
Increased granulocyte precursors: myelocytes and metamyelocytes (‘left shift’).
Test for infectious mononucleosis?
Monospot test or looking for IgM antibodies to Epstein-Barr Virus (EBV).
Metabolic effects of leukaemia?
High levels of uric acid and renal failure
What is a specific indicator of bacterial infection seen in neutrophils on blood film?
Presence of clear vacuoles within the cytoplasm of the neutrophils.
How to optimise image when using a light microscope?
Step 1: Focus the image. Step 2: Focus the condenser. Step 3: Adjust the field iris. Step 4: Adjust the condenser iris.
