Anaemia Flashcards
In terms of red cells, what does a high unconjugated bilirubin suggest? Why?
It indicates haemolysis as when red cells breakdown one of the products is unconjugated bilirubin
In terms of red cells, what does a high conjugated bilirubin suggest? Why?
A problem in the liver, if it was to do with red cells the bilirubin would be unconjugated, conjugation of bilirubin occurs in the liver
Is LDH intra or extra cellular?
Intracellular
In relation to reticulocytes, what is the normal response in anaemia?
Increase the production of reticulocytes, those with anaemia should have a high reticulocyte count
What does anaemia with low reticulocytes indicate?
There is a problem with RBC production
What are indicators of haemolysis when looking at bloods?
High unconjugated bilirubin
Raised LDH
Reduced haptoglobulins
What are the 4 mechanisms of anaemia?
Reduced production of RBCs
Increased clearance of RBCs in circulation
Blood loss
Pooling of cells in the spleen
What are some causes of reduced red cell survival?
Hereditary spherocytosis
G6PD deficiency
Autoimmune haemolytic anaemia
What are some causes of reduced red cell production?
Anaemia of chronic disease
Iron deficiency anaemia
Megaloblastic anaemia
How does chromia of red cells differ when cells are macrocytic vs normocytic vs microcytic
Microcytic: hypochromia
Normocytic: normochromia
Macrocytic: normochromia
What are the common causes of microcytic anaemia?
Deficiency in haem synthesis (iron deficiency anaemia or anaemia of chronic disease)
Deficiency in globin synthesis (alpha or beta thalassaemia)
How can we differ between anaemia of chronic disease and iron deficiency anaemia?
Ferritin will be high in chronic but low in iron deficiency, transferrin will be normal/low in chronic but high in iron deficiency
How does electrophoresis allow us to differentiate between alpha and beta thalassaemia?
In alpha thalassaemia, the HbA2 will be normal but in beta it will be raised
How do we differentiate between iron deficiency anaemia and thalassaemia?
Haemoglobin will be low in iron deficiency but normal an thalassaemia, RBC will be low in iron deficiency but raised in thalassaemia
What are common causes of macrocytic anaemia?
Vitamin B12 and folic acid deficiency
Drugs that interfere with DNA synthesis
Liver disease and ethanol toxicity
Haemolytic anaemia
What are some common causes of normocytic anaemia?
Recent blood loss
Failure of production red cells
Pooling of red cells in the spleen
Define haemolysis
Destruction of red cells
What is the lifespan of a normal red cell?
150 days
What pathway provides energy to red cells?
The glycolytic pathway
What enzyme is involved in the glycolytic pathway? How is it significant?
G6PD enzyme, it is rate limiting
How is G6PD deficiency inherited?
X linked recessive (mainly present in men)
What occurs relating red cells when there is G6PD deficiency?
Haemolysis
How will MCV be affected if there are lots of reticulocytes?
It will increase as reticulocytes are larger than RBCs
How do RBCs and reticulocytes compare in terms of size?
Reticulocytes are larger
What will you see on a blood film of someone with G6PD deficiency?
Hyperchromatic cells
Abnormally shaped cells
Heinz bodies
Ghost cells
What are heinz bodies and how do they form?
Haemoglobin is subject to oxidative damage and becomes precipitated and oxidised, causing it to clump together
What are ghost cells?
Smaller and more condensed cells
What type of cells are a feature of intravascular haemolysis?
Ghost cells
What type of cells are a feature of extravascular haemolysis?
Spherocytes
What advice is given to patients with G6PD deficiency?
Avoid oxidant drugs
Dont eat broad beans/fava beans
Avoid naphthalene
Be aware haemolysis can result from infection
Is LDH intracellular or extracellular?
Intracellular
What are some non immune ways haemolytic anaemia can be acquired?
Malaria
Snake venom
Drugs
Haemolytic uraemic syndrome
What is the test to determine if haemolytic anaemia is autoimmune or not?
Direct antiglobulin test (DAT)
What does the DAT stand for? How does the DAT work?
Direct antiglobulin test
RBCs are suspended in saline
Rabbit antibodies are added to the sample, they bind to autoimmune antibodies on the RBC surface if present
This causes agglutination and confirms a positive result
What is allo-immune anaemia?
Anaemia that occurs after a blood transfusion
What does allo imune mean?
Post blood transfusion
What type of anaemia can cause gallstones?
Haemolytic anaemia
What is hereditary spherocytosis?
An inherited disorder where RBCs become sphere shaped due to bits of the membrane breaking off
How do spherocytes look on a blood film?
Reduced diameter
Lack central pallor
Very round
How are RBCs lost in hereditary spherocytosis?
They pool in the spleen and are removed
What should reticulocyte count be in someone with hereditary spherocytosis?
High
How is hereditary spherocytosis treated?
Giving folic acid if need is increased
Splenectomy if its severe (this increases the lifespan of the red cells)
Why does megaloblastic anaemia arise?
Due to B12 or folate deficiency
What is different about the organelles in megaloblastic anaemia?
The nucleus isnt maturing and developing but the cytoplasm is
What is B12 needed for?
DNA synthesis and integrity of the nervous system
What molecule is needed to allow absorption of B12? Where is it found?
Intrinsic factor
Made in the parietal cells of the stomach
What is a common cause of destruction of stomach parietal cells?
Pernicious anaemia
What is transferrin used for?
Transporting iron from the gut
What is ferritin for?
Iron storage
What are transferrin and ferritin levels in someone with anaemia of chronic disease?
Transferrin is low
Ferritin is high
What happens to reticulocyte count in anaemia of chronic disease?
It remains low as theres no compensatory response
What is the usual cause of anaemia of chronic disease?
Low iron levels due to conditions like TB, HIV, rheumatoid arthritis, autoimmune disorders, malignancy etc
What is ESR and what does it indicate?
Erythrocyte sedimentation rate, it indicates inflammation levels, if inflammation is high ESR will also be raised
What will patients with iron deficiency anaemia present with?
Fatigue
Breathlessness when resting and worse on exertion
Ankle swelling at the end of the day
What levels will show on the blood film of someone with iron deficiency anaemia?
Low haemoglobin, MCV, MCH, RBC
High platelets
What happens to MCV in megaloblastic anaemia?
It is high
Describe serum iron, ferritin and transferrin levels in iron deficiency anaemia
Ferritin and serum iron is low
Transferrin is high
What questions can you ask if you suspect iron deficiency anaemia?
Are the vegetarian/vegan?
Do they have any GI symptoms eg dysphagia, dyspepsia, change in bowel habits
What medications are they on? (NSAIDs/aspirin?)
What are the 3 main causes of iron deficiency anaemia?
Blood loss- hookworm most commonly, also menorrhagia
Insufficient iron intake- eg vegetarian/vegan diet
Increased requirement- pregnant, in infancy
What will you see on a blood film of someone with iron deficiency anaemia?
Microcytosis
Hypochromia
Occasional target cells
Pencil cells (elliptocytes)
What investigations can be undertaken when iron deficiency anaemia is suspected?
Faecal immunochemical test to investigate blood in the stool
GI investigations eg endoscopy, duodenal biopsy, colonoscopy
Coeliac antibody testing
How does excretion of iron work?
Iron is not physiologically excreted yet absorption is tightly controlled
How much iron is absorbed daily?
1-2mg from the diet
Why is excess iron dangerous?
It is toxic to the body
What molecule regulates iron absorbtion?
Hepcidin
