Theme 2 - Anaemia Flashcards
what are the signs of anaemia (seen by doctor)
- increased pulse and respiratory rate
- spoon nails (kolionychia)
- pale conjunctiva
- tachycardia
What are the symptoms of anaemia (described by the patient)
NON SPECFIC SYMPTOMS
- lethargy
- palpitations
- dyspnoea
- headaches
what defines anaemia?
a fall in Hb concentration below defined levels (160g/L for women and 180g/L in men) therefore insufficient oxygen delivery to tissues
what are the five broad causes of anaemia?
1) bleeding
2) deficiencies - iron, folic acid, B12
3) haemolysis - red cell fragility
4) BM dysfunction - myelodysplasia
5) poor oxygen utilisation or carriage in blood
what are three questions that should be asked when investigating anaemia?
1) Red cell size (MCV)?
2) is it acute or chronic?
3) what is the underlying aetiology?
what is the most common type of anaemia and what is its main cause?
Iron deficiency caused by bleeding (can also be caused by deficiencies or increased requirements eg in pregnancy)
how is occult bleeding diagnosed?
melenaea - dark stool
what are the four principle iron studies two confirm iron deficiency?
1) serum ferritin
2) serum iron
3) serum transferrin
4) % transferrin saturation
how is serum ferritin implicated in anaemia?
IT IS DECREASED
- is the storage form of iron
- increased in iron overload and decreased in iron deficiency
- can also be affected by genetics or in a blood transfusion
what is serum transferrin and how is implicated in anaemia?
IT IS INCREASED
- carrier molecule for iron
- picks up iron from the gut
- if there is iron deficiency then the body up regulates it
how is serum iron implicated in anaemia?
ISNT REALLY
- only reflects recent iron intake therefore if its normal it doesn’t exclude a deficiency
how is % transferrin saturation implicated in anaemia?
GOOD and SENSITIVE MEASURE - LOW IN DEFICIENCY
- shows how much transferrin actually has iron bound to it
- lower if patient is iron deficient
what are the three characteristics in FBC of iron deficiency?
- low serum ferritin (can be normal)
- increased serum transferrin
- low transferrin saturation
how is anaemia of chronic disease characterised?
patient has problem getting iron from the stores to the RBC
- not an iron deficiency
- low transferrin and high or normal ferritin, low serum iron
- %TF saturation is normal
- low EPO (kidney failure)
what generally happens to EPO levels in anaemia?
It is increased as it is released in response to low oxygen levels (as Hb is lower in anaemia)
how much iron taken in from the diet is absorbed and where?
1% absorbed in the duodenum
how long do B12 body stores last?
3-4 years
how long two body folate stores last?
a few months
where is B12 absorbed and how?
in the terminal ileum by receptors for intrinsic factor
how is microcytic anaemia characterised?
- Low MCV (<80)
- Iron deficiency
- beta thalassemia
how is macrocytic anaemia characterised?
- large MCV (>100)
- B12 or folate deficiency (megaloblastic)
- alcoholic liver disease (non megaloblastic)
What is normocytic anaemia caused by?
- anaemia of chronic disease
- haemorrhage
How is the underlying cause of anaemia identified?
on a blood film
what can be identified on a blood film?
the underlying cause of anaemia
- deficiencies due to cell size
- Haemoglobinopathies eg SCA
- polychromasia - high reticulocytes (red cell fragility)
