Anaemia and Thrombocytopenia Flashcards
What haematinic deficiencies can lead to anaemia?
o Iron
o Vitamin B12
o Folate
Common causes of anaemia:
- Blood loss
- Haematinic deficiencies
- Secondary to chronic disease
- Haemolysis
- Alcohol, drugs, toxins
- Renal impairment – EPO
- Primary haematological/ marrow disease e.g. malignant, Hb disorders (sickle etc), congenital, aplasia
What is pernicious anaemia?
Inability to absorb B12 and iron (e.g. in atrophic gastritis) leading to anaemia
What is the MCV?
Mean cell volume i.e. how big your red cells are
What is the term for an elevated MCV?
Macrocytic: when the MCV value is increased, the RBCs are abnormally large.
What is macrocytic MCV typically seen in?
o B12, folate deficiencies (megaloblastic anemias)
o Metabolic e.g. thyroid/liver disease
o Marrow damage (alcohol, drugs, marrow disease)
o Haemolysis
How can haemolytic anaemia lead to a macrocytic MCV?
RBCs are broken down quickly and young red cells (called reticulocytes) are released into the blood by the marrow to compensate.
Reticulocytes are larger than normal RBCs.
What is the term for anaemia with a normal MCV?
Normocytic
What is normocytic MCV seen in?
o Anaemia of chronic disease
o Inflammatory
o Acute blood loss
What is the term for an reduced MCV?
Microcytic
What is microcytic MCV typically seen in?
o Iron deficiency
o Haemoglobin disorders
o Sometimes chronic disease
What is the most common cause of microcytic anaemia?
Iron deficiency
Potential causes of iron deficiency in;
a) children
b) young women
c) older
a) diet, growth, malabsorption
b) menstrual loss/problems, pregnancy (don’t underestimate long-term impact of pregnancy on iron levels), diet
c) bleeding, GI problems (ulcer, aspirin, gastritis)
Why is it very easy to become iron deficient?
Body only absorbs a limited amount of iron (7% TDI) due to having no excretory mechanism. Most iron is thus recycled.
Where is iron absorbed?
Absorbed in the duodenum (less in jejunum)
What is iron transported by?
Transferrin
Where is iron stored?
ferritin/haemosiderin
How should you approach an iron deficiency?
- Establish that there is a low iron
- Find cause
- Treat iron and cause
What is the initial investigation in iron deficiency?
FBC, indices, film
Describe the RBC indices in iron deficiency?
MCV will be low in iron deficiency
What is the most important diagnostic test in iron deficiency?
Ferritin
What is ferritin?
Ferritin is a blood protein that contains iron.
If a ferritin test reveals that your blood ferritin level is lower than normal, what does this indicate?
low ferritin = iron deficiency
What are hypochromic cells?
Hypochromia means that the red blood cells have less color than normal when examined under a microscope
What does a higher % of hypochromic cells indicate?
iron deficiency
What is the MCH?
The mean corpuscular hemoglobin , or “mean cell hemoglobin”
Describe the MCH value in hypochromic anaemias?
MCH value is diminished in hypochromic anemias.
4 main investigations in iron deficiency?
- FBC, indices, film
- Ferritin
- %hypochromic cells
- Serum iron/TIBC
What are the 3 types of iron therapy?
o Oral iron: often unreliable, unpleasant, not good compliance
o IM iron: painful, out of date
o IV iron: increasingly used.
What is megaloblastic anaemia?
Refers to description of appearance of abnormally large RBCs
- Proper term is the characteristic cell morphology caused by impaired DNA synthesis
- Used to describe raised MCV due to B12/folate deficiency
- RBCs are larger with high MCV
What is the most common cause of megaloblastic anaemia?
B12 and/or folic acid deficiency
How can B12 and/or folic acid deficiency lead to megaloblastic anaemia?
DNA has purine/pyrimidine bases which require folate for the synthesis.
B12 is essential for cell folate generation. Low folate or B12 starves DNA of bases.