Anaemia Flashcards
Generally speaking what is anaemia? What are the three broad causes of anaemia?
When the Hb concentration falls below a defined level.
Decreased RBC’s, decreased Hb content, altered Hb
Why can pregnant women sometimes be described as anaemic?
They produce more Hb however still have anaemia as the Hb is diluted in larger volume of plasma
Describe how chronic and acute anaemia differ in their presentation in patients.
Acute anaemia (ie. in haemorrhage) may cause non-specific symptoms such as lethargy, shortness of breath, palpitations and headaches.
Chronic patients may be asymptomatic as their bodies can often compensate for low Hb.
What are the four clinical signs of anaemia?
- Pallor, pale conjunctivae
- Koilonychia (spoon shaped nails, characteristic of iron deficiency)
- Tachypnoea
- Tachycardia
Describe 5 causes of anaemia
- Haemorrhage
- Deficiency (iron, folic acid and vitamin B12)
- Poor O2 utilisation/ carriage
- Haemolytic
- Bone marrow dysfunction as in aplastic anaemia
How can anaemia be classified?
Size of RBC
Underlying aetiology
Acute/Chronic
Describe hypochromic microcytic anaemia in terms of prevalence, cause and effects.
How is it tested?
Most common
Causes: bleeding (menstruation, GI bleeds from GI malignancy, GI peptic ulceration), malnutrition/veganism (Red meat greatest supply of , malabsorption states i.e. in Chrohns, pregnancy.
Tests:
- Ferritin g
- Transferrin
- Serum
Describe the usefulness of the tests for iron.
- Ferritin gives conclusive result, low ferritin= iron deficiency. High ferritin= haemochromotosis
- Transferin homeostatically goes up if iron deficient.
Similar to the TIBC (Total iron binding capacity). Percentage transferrin is sensitive measure of iron. Low= iron deficient - Serum is labile so reflects recent intake
Give an example for a microcytic, normocytic and macrocytic anaemia.
Microcytic- Iron deficiency, Hb disorders e.g. thalassaemia
Normocytic- sickle cell, aplastic
Macrocytic - B12 and folic acid, myelodysplasia
Why might we use a blood film in diagnosis of iron deficiency?
Its easy and quick
Can observe pencil cells, target cells (dark perimeter with horseshoes. shape white centre).
In hypochromic microcytic anaemia the white space in the cell is greater than 1/3 the diameter.
What does the reticulocyte count tell us?
How is it measured?
It represents RBC production rate by marrow. Low if bone marrow infiltrated or precursor deficiency (Iron)
High in haemolysis, chronic bleeding
If normal in anaemic patient, shows that bone marrow is not responding appropriately
Measured by flow cytometry
Describe pernicious anaemia
Caused by B12 deficiency
Can be due to autoimmunity (parietal cell loss) or deficiency in intrinsic factor.
Both cause malabsorption of B12. However, post gastric surgery and Crohns disease also have same effect
Descrive anaemia of chronic disease
Disease being TB which causes chronic inflammation, rheumatoid arthritis, cancer.
Iron stuck in reticuloendothelial system (poor utilisation)
Most common anaemia in hospitalised patients
Dysregulation of iron homeostasis causing decreased transferin and increased hepcidin.
Impaired proliferation of erythroid progenitors
Describe sickle cell anaemia
What happens in a crisis?
Treatment?
Mutation in b-globin gene results in HbS
Triggered by low O2 in blood
Vaso-occlusion leads to ischaemia, pain, necrosis and organ damage
Analgecs, hydration
What happens in thalassaemia? Appearance?
What is its genetic make up?
Insufficient Hb production dueto altered Hb
Enlarged spleen, liver and heart
Autosomal recessive
Microcytic, hypochromic
