Blood cell abnormalities Flashcards
What is anaemia?
Reduction in the amount of haemoglobin in a given volume of blood below normal values for health subject of same age and gender
What are the 4 mechanisms of anaemia?
Reduced production of red cells
Blood loss
Reduces serval of red cells
Pooling of red cells in very large spells
What is caused by reduced production of globing chains?
Thalassemia
How can anaemia be classified?
On the basis of cell size
What are causes of microcytic anaemia?
Defect in haem synthesis -Iron deficiency -Anaemia of chronic disease Defect in globing synthesis -alpha thalassaemia -beta thalassaemia
What causes iron deficiency?
Increased blood loss Insufficient intake Increased requirements (pregnancy and infancy)
What are the causes of macrocytic anaemia?
Megaloblastic anaemia Abnormal haemopoiesis Liver disease Excess alcohol intake Increased no. of reticulocytes
What is megaloblastic anaemia?
Delay in maturation of the nucleus while the cytoplasm continues to mature and cell grows
What is a megaloblast?
Abnormal bone marrow erythroblast
What causes megaloblastic anaemia?
Deficiency of B12 or folic acid
Use of drugs interfering with DNA synthesis
Liver diseases increased ethanol toxicity
Recent major blood loss
Haemolytic anaemia
What is polycythaemia?
Too many red cells in the circulation
What are the two types of polycythaemia?
Pseudo- reduced plasma volume
True- increase in total volume of red cells in circulation
What causes polycythaemia?
Excessive transfusion
Response to hypoxia
Changes in levels of erythropoietin
Abnormal function of the bone marrow
What can cause increased synthesis of erythropoietin?
High altitude
When is an increase in erythropoietin inappropriate?
In sports
In cancer e.g renal tumours secrete it
What is polycythaemia vera?
Intrinsic bone marrow disorder
Myeloproliferative neoplasm
What does polycythaemia result in?
More viscous blood
Can lead to vascular obstruction
What is leukaemia?
Cancer of the blood
Means ‘white blood’
5% of all cancers
What causes leukaemia?
Series of mutation in a single lymphoid or myeloid stem cell
The progeny behave abnormally e.g. increased proliferation, failure of differentiation, increased survival
Cells with mutations have a growth advantage
What is different about leukaemia?
Stem cells can circulate in blood and enter tissues
Concepts of invasion and metastasis cannot be applied
Therefore terms chronic and acute are uses
Chronic- benign
Acute- malignant
How is leukaemia classified?
Acute or Chronic
Lymphoid: (B or T or NK)
Myeloid: (Granulocytic or Monocytic or Erythroid or Megakaryocytic)
What does the suffix ‘blastic’ mean?
Acute
What does the suffix ‘cytic’ mean?
Chronic
Why do people get leukaemia?
Random errors
Oncogenic influences
Loss of function in tumour suppression gene
What are the differences between acute and chronic leukaemia?
AML- cells continue to proliferate but no longer mature
Build up of immature cells
Failure to produce normal functioning end cells
Cell behaviour profoundly disturbed
CML- leukaemia cells are mature although abnormal
How does leukaemia cause diseases characteristics?
Leucocytosis causes bone pain
Enlargement of thymus, spleen etc.
What is chronic myeloid leukaemia?
Translocation between chromosome 9 and 22 in haemopoietic stem cell
A chimeric gene is formed
Gives cell growth and survival advantage gives rise to a leukaemic clone
Increase in granulocytes and precursors
Anaemia
Enlarged spleen
What is acute lymphoblastic leukaemia?
Leucocytosis Anaemia Neutropenia Thromobocytopenia Replacement of normal bone marrow by lymphoblasts More common in children
What can molecular genetic analysis do?
Give more information about prognosis
Development on targeted treatment
What is the treatment for acute lymphoblastic leukaemia?
Red cells for anaemia Platelets for haemorrhages Antibiotics Systemci chemo Intrathecal chemo
What are the causes of normocytic anaemia?
Iron deficiency
Renal failure
Recent blood loss
Bone marrow failure/ infiltration
