Week 1- Approach to anaemia and diagnosis Flashcards
What are the two definitions of anaemia?
Reduction in haemoglobin concentration which is below that which is optimum for the individual. Reduction in haemoglobin concentration below 95% of the population range.
What Hb concentration in children (6 months to 6 years) below which anaemia is likely to be present?
110g/L
What Hb concentration in children (6-14 years) below which is anaemia likely to be present?
120g/L
In adult men, what Hb concentration below which anaemia is likely to be present?
130g/L
In adult women, what Hb concentration below which anaemia is likely to be present?
120g/L
In pregnant women, what Hb concentration below which anaemia is likely to be present?
110g/L
What two broad categories is anaemia classified into? (Just a way of thinking about what causes the problem rather than a diagnosis)
Decreased production- hypo proliferative (reduced amount of erythropoeisis) Maturation abnormality- erythropoiesis present but ineffective. Increased destruction-bleeding, haemolysis
How can anaemia’s reticulocyte response be divided?
Increased response or decreased response. If its an increased response its likely to be increased destruction of cells (haemolysis or blood loss). If it is a decreased response from the reticulocytes there is either something wrong with the red blood cells, or not enough proliferation is occuring.
What does reticulocytosis mean? What is the significance of this?
Increased reticulocytes. It means red cell production has increased.
How can you tell clinically if someone is haemolysing their red blood cells prematurely?
You can get increased bilirubin and therefore jaundice. And also increased urinary urobilinogen. Also get hypertrophy of macrophage rich tissues (these breakdown the RBC’s therefore get bigger). Can get splenomegaly and hepatomegaly.
This is v helpful to remember.
What is haemolytic anaemia?
Anaemia due to haemolysis.
What is the normal body response to anaemia?
The EPO should increase, causing erythropoeisis to increase.
How much can normal marrow increase its erythropoeisis by?
3-4 fold.
What can your MCV be described as?
Normocytic (normal)
Macrocytic- big
Microcytic- small
What is the commenest cause of hypochromic, microcytic anaemia?
Iron deficiency.
What are some other less common causes of anaemia?
Thalassaemias
Anaemia of chronic disease
Sideroblastic anaemia (bone marrow produces ringed sideroblasts rather than healthy RBCs)
Nutritional causes for macrocytic anaemia?
B12 or folate deficiency (you get immature cells as they cant undergo DNA replication without these, this means they will be bigger).
Name some other causes of macrocytic anaemia?
Myelodysplagia
myeloma
aplastic anaemia (stem cells are damaged causing pancytopenia)
Reticulocytosis
Cold agglutinins
What can cause macrocytosis without anaemia?
Alcohol
Liver disease
Hypothyroidism
What can cause normocytic normochromic anaemia?
Acute blood loss or early in iron deficiency
Hypoproliferative- low reticulocyte count- (they havent had time to respond yet.
Could be due to chronic diseases, anaemia of renal failure, hypometabolic states, marrow failure
Why does renal failure cause a failure in reticulocytosis?
Renal failure means EPO is not produced therefore the bone marrow isnt stimulated.
How can an inflammatory stimulus result in anaemia?
It activates T cells and monocytes
Which inhibit EPO release, increase hepatic synthesis of hepcidin, augment hemophagocytosis and inhibit erythroid proliferation.
How can you distinguish between iron deficiency anaemia and anaemia of chronic disease?
Iron deficiency- low ferritin and transferase. MCV will be reduced.
Chronic disease- normal/high ferritin and low transferase. MCV will also be normal.
