🫀🫁Cardio & Resp🫀🫁 - Anaemia Flashcards
What abnormalities can be seen in this blood film?
Spherocytes
Liver function tests show bilirubin of 30μmol/l (normal range <17), and the bilirubin was mainly unconjugated.
What does this tell us?
Pre-hepatic jaundice
High unconjugated bilirubin, and spherocytes on the blood film. What does this tell us?
Hereditary spherocytosis, leading to jaundice due to increased destruction in the spleen
What will also be seen in the blood of someone with increased erythrocyte destruction?
High reticulocyte (immature RBC) count
How are reticulocytes identifiable on a blood film?
Slightly larger with a bluish tinge
What causes the bluish tinge in reticulocytes?
Higher RNA content
How does spherocytosis occur?
Disruption of vertical linkages in membrane
Usually ankyrin/spectrin
What happens due to hereditary spherocytosis?
Haemolysis or haemolytic anaemia
Can result in jaundice
Increase in bone marrow production - leads to young cells found in blood
What is the difference between haemolysis and haemolytic anaemia?
Haemolysis is increased RBC destruction (reduced RBC survival)
Haemolytic anaemia is haemolysis that can’t be compensated for - leads to reduction in Hb
How would someone with haemolytic anaemia by treated?
Folic acid (because of increased erythropoiesis demand)
Splenectomy (if severe) to increased RBC life span
Patient with hereditary spherocytosis diagnosis presents several years later acutely with upper right abdominal pain and tenderness, marked jaundice and high bilirubin, this time conjugated.
What has happened?
Likely gallstones from increased breakdown of haemoglobin to bilirubin
One of the gallstones has obstructed the CBD - obstructive jaundice
Is post hepatic - hence conjugated bilirubin
What is AIHA?
Autoimmune haemolytic anaemia
Usually found in multi-system autoimmune conditions (e.g. SLE)
What would you see in AIHA blood count?
Low Hb (increased RBC destruction)
High MCV (reticulocytes)
Increased reticulocyte count
High bilirubin
LDH - due to tissue damage
What is the DAT?
Direct antiglobulin test
Tests for antibodies that bind to RBCs
What is the mechanism of RBC destruction in AIHA?
Autoantibodies bind to RBCs
Results in destruction in the spleen
Spherocytes are present in which two blood disorders?
Hereditary spherocytosis
AIHA
What test can distinguish between hereditary spherocytosis and AIHA?
DAT
What is the most common enzyme deficiency that results in anaemia?
G6PD deficiency
What does a G6PD deficiency result in for a RBC?
Inhibits the pentose shunt
Key process that protects the RBC from oxidant damage
How does G6PD lead to more oxidative damage being received by a RBC?
G6PD deficiency reduces the ability of red blood cells to regenerate glutathione, a critical antioxidant
What type of jaundice will be exhibited in someone with G6PD deficiency?
Pre-hepatic jaundice
Unconjugated bilirubin
What would you expect to see in the blood count of someone with anaemia caused by G6PD deficiency?
Low Hb
High MCV
High reticulocytes
Classic haemolysis
What will you see in the blood film of someone with G6PD deficiency?
Ghost cells
Heinz body
Hemighosts
(cells with haemoglobin abnormalities due to oxidising damage)
What advice should be given to patients with G6PD?
Avoid oxidant drugs
Don’t eat broad beans (fava beans)
Avoid napthalene
Be aware that haemolysis can result from infection
How can haemolytic anaemia be categorised?
Haemolysis can result from an intrinsic abnormality of the red cells
Haemolysis can result from extrinsic factors acting on normal red cells
ALTERNATIVELY
Inherited haemolytic anaemia can result from abnormalities in the
cell membrane, the haemoglobin or the enzymes in the red cell
Acquired haemolytic anaemia usually results from extrinsic factors
such as micro-organisms, chemicals or drugs that damage the red cell
Extrinsic factors can interact with red cells that have an intrinsic
abnormality
How can haemolytic anaemia be classified in terms of vascularity?
Intravascular haemolysis - occurs when there is acute damage to the RBC
Extravascular haemolysis - defective RBCs removed by the spleen
What general things would you be looking for in haemolytic anaemia?
Otherwise unexplained anaemia, normochromic and either normocytic or macrocytic
Evidence of morphologically abnormal red cells
Evidence of increased red cell breakdown
Evidence of increased bone marrow activity
Give a summary of the inherited haemolytic anaemias
Give a summary of the acquired haemolytic anaemias
Would would you expect to see in the blood count of someone with iron deficiency anaemia?
Low Hb
Low MCV (microcytic anaemia)
Low MCH and MCHC
Low RBC
High platelets