Anaemia and polycythaemia Flashcards Preview

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Flashcards in Anaemia and polycythaemia Deck (25)
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Define "anaemia"

A reduction in the amount of haemoglobin in a given volume of blood below what would be expected in comparison with a healthy subject of the same age and gender


Recall 4 MECHANISMS of anaemia

1. Reduced red cell/ Hb production
2. Pooling of red cells in large spleen
3. Blood loss
4. Reduced red cell survival


What is defective in microcytic anaemia? Recall 3 causes

Haemoglobin synthesis
Defects in haem synthesis: iron deficiency
Defects in globin synthesis: alpha thalassaemia, beta thalassaemia


What name is given to anaemia caused by abnormal haemopoiesis? What classification is it given and why?

Megaloblastic anaemia (failure of DNA synthesis)
MACROCYTIC - delay in maturation of the nucleus while the cytoplasm continues to mature and the cell continues to grow


What is the most common cause of megaloblastic eryhtropoiesis?

B12 deficiency


Recall 7 possible causes of macrocytic anaemia

1. Vit B12 def.
2. Folic acid def.
3. Recent major blood loss
4. Drugs that interfere with DNA synthesis
5. Alcohol toxicity
6. haemolytic anaemia
7. Liver disease


Why would haemolytic anaemia be macrocytic?

Number of reticulocytes increased, and they are 20% bigger than mature cells


What could be a cause of pooling of red cells in an enlarged spleen?

Portal cirrhosis


Recall 3 possible causes of normacytic normachromic anaemia

1. Recent blood loss
2. Failure of red cell production
3. Pooling in hypersplenism


Recall 3 possible causes of rec cell production failure

1. Bone marrow suppression by cancer drugs
2. Bone marrow infiltration by cancer
3. early stages of a deficiency (B12/FA/ renal fx)


Recall 5 hereditary causes of haemolytic anaemia

1. Protein deformation
2. Spherocytosis
3. Sickle Cell
4. Pyruvate kinase deficiency
5. G6PD deficiency


Recall the aetiology of hereditary spherocytosis leading to haemolytic anaemia

1. Cells lose section of membrane in spleen
2. Premature removal from spleen
3. Bone marrow responds by increasing activity --> polychromasia and reticlocytosis
4. Cells more likely to haemolyse when osmotic pressure applied


What is G6PD essential for in erythrocytes?

Prevention of oxidant damage


Recall 3 possible extrinsic oxidants that may cause G6PD deficiency

1. Drugs
2. Broad beans
3. Napthalene (moth balls)


Who is most at risk of G6PD deficiency and why?

Hemizygous males, as the G6PD gene is on the X chromosomes


Describe the blood film of someone with haemolytic anaemia caused by G6PD deficiency

Many irregularly contracted cells
Heinz bodies


What causes Heinz bodies?

Denatired DNA


Describe the aetiology of autoimmune haemolytic anaemia

Production of AutoIg-M which is directed at red cells
IgM recognised by splenic macrophages and phagocytosed, leading to loss of membrane and spherocytosis


Recall the 5 principles of diagnosis for haemolytic anaemia

1. Normachromic
2. Normacytic or macrocytic
3. Morphologically abnormal red cells
4. increased red cell breakdown
5. Increased bone marrow activity


Recall the aetiology of biliary system complications in haemolytic anaemia

Heamolysis > bilirubin production increased > jaundice + gall stones


What 2 things might be seen on the blood film of someone with haemolytic anaemia?

Increased #reticulocytes


Recall the first line of treatment for haemolytic anaemia

Corticosteroids and other immunosuppressants


What measures are elevated in polycythaemia

Red cell count


WHat is the difference between pseudopolycythaemia and true polycythaemia?

Pseudopolycythaemia - results from decreased plasma vol
True polycythaemia - results from increased red cell number


Recall 4 possible causes of polycythaemia

1. Blood doping
2. Too much erythropoietin
3. Renal carcinoma
4. Abnormal bone marrow fx (eg polycythaemia vera)