Introduction to Anaemia Flashcards
What is the definition of anaemia?
Reduced total red cell mass
What are the two main surrogate markers used to measure total red cell mass?
Haemoglobin concentration and haematocrit
What would be a normal Hb level for each of the following groups: a) men? b) adult females and children aged 6-14 years? c) pregnant females and children aged 6 months to 6 years?
a) > 130g/L b) > 120g/L c) > 110g/L
What is the haematocrit?
The ratio or percentage of the whole blood sample that is made up of red cells if the sample was left to settle
What are some rarer situations where Hb and haematocrit are not good markers of anaemia?
Early on in a severe, rapid bleed and in haemodilution
Aside from red cell indices, what are some further investigations which could be done to assess for anaemia?
Blood film, reticulocyte count and other additional tests depending on clinical findings
What blood test is the most useful tool in distinguishing between nuclear and cytoplasmic deficits?
Mean cellular volume (MCV)
If Hb and MCV are low, what is this known as? You should consider a problem with what?
Microcytic anaemia / haemoglobinisation of the red blood cell
If Hb is low and MCV is high what is this known as? You should consider a problem with what?
Macrocytic anaemia / maturation of the red blood cell
In terms of the pathophysiology of anaemia, it can be due to what two things?
Decreased production of red blood cells or increased loss/destruction of red blood cells
What happens to the reticulocyte count if the cause of an anaemia is decreased production of red blood cells?
It is low
What happens to the reticulocyte count if the cause of an anaemia is increased loss or destruction of red blood cells?
It is high
What are the two subgroups of causes which come under ‘decreased production of red blood cells’?
Hypoproliferative (reduced erythropoiesis) or a maturation abnormality which causes ineffective erythropoiesis
Impaired haemoglobinisation is caused by a defect where?
Cell cytoplasm
Impaired red cell division and maturation is caused by a defect where?
Cell nucleus
What are the two main causes of increased loss/destruction of red blood cells?
Bleeding and haemolysis
What is haemolysis? What is the compensatory mechanism to this?
Premature red cell destruction in the circulation / increased red cell production in the bone marrow
What are reticulocytes?
Red blood cells which have just left the bone marrow
How do reticulocytes appear different to mature erythrocytes?
They are larger and they stain deep purple/red known as ‘polychromasia’
Why do reticulocytes stain deep purple/red?
They still contain some RNA
Reticulocyte count is a marker of what?
Red cell production
If there are increased reticulocytes, this indicates what?
Either blood is being lost or the patient is haemolysing
Reticulocytosis can be a sign of both blood loss and haemolysis. What other factors would point more towards a diagnosis of haemolysis?
Increased red cell breakdown products e.g. unconjugated serum bilirubin and urinary urobilinogen
What is the result of producing increased red cell breakdown products?
Anaemia and jaundice, sometimes splenomegaly
Why can anaemia be asymptomatic?
Since a slowly falling Hb can be compensated for by a rise in 2,3-DPG causing a shift of the oxygen dissociation curve to the right to allow oxygen to be more readily given up to the tissues
What are the main non-specific symptoms of anaemia?
Tiredness, headache, faintness, breathlessness
What are the main non-specific signs of anaemia?
Pallor, tachycardia, systolic murmur
