Haemolytic Anaemia Flashcards
What is haemolytic anaemia?
Anaemia due to shortened RBC survival
How long do RBCs circle for?
Approx 120 days
Where are senescent RBCs removed?
Reticular endothelial system (RES )of the liver and spleen
How long do haemolytic anaemia RBCs survive for?
30-80 days (down from 120 days)
What does the shortened red cell survival mean for the blood?
Increased RBC production and increased young cells in circulation → reticulocytosis
What does bone marrow do during haemolysis?
- Bone marrow compensates by increasing its output of red cells 6-8 fold→ increasing the proportion of red cells produced, expanding the volume of active marrow
What is incomplete compensated haemolysis?
When RBC production is unable to keep up with decreased RBC lifespan → decreased haemoglobin
What are the symptoms of haemolytic anaemia?
- Jaundice
- Pallor
- Fatigue
- Splenomegaly
- Gallstones
- Leg ulcers
- Folate deficiency line folate use in RBC production
What would a peripheral blood film show in haemolytic anaemia?
- Polychromatophilia
- Nucleated RBC
- Thrombocytosis
- Neutrophilia with left shift
What happens to the bone marrow in haemolytic anaemias?
Erythroid hyperplasia
What does haemolytic anaemia cause in the bone marrow?
- Increase in unconjugated bilirubin, lactate dehydrogenase, urobilinogen and urinary haemosiderin
- Decrease serum haploglobin protein that binds free haemoglobin
What does erythroid hyperplasia cause?
- Normoblastic reactions
- Reversal of myeloid: erythroid ratio
- Variable reticulocytosis
What are the general classifications of haemolytic anaemia based on?
- Inheritance
- Site of RBC destruction
- Origin of RBC damage
What are the inheritance classifications of haemolytic anaemia?
- Hereditary
- Acquired
What are the site of RBC destruction classifications of haemolytic anaemia?
- Intravascular
- Extravascular
What are the origin of RBC damage classifications of haemolytic anaemia?
- Intrinsic
- Extrinsic
What is an example of hereditary haemolytic anaemia?
- Hereditary spherocytosis
What is an example of acquired haemolytic anaemia?
Paroxysmal nocturnal hemoglobinuria (PNH)
What is an example of intravascular haemolytic anaemia?
Thrombotic Thrombocytopenic Purpura (TTP)
What is an example of extravascular haemolytic anaemia?
Autoimmune haemolysis
What is an example of intrinsic haemolytic anaemia?
G6PD deficiency
What is an example of extrinsic haemolytic anaemia?
Delayed haemolytic transfusion reaction
What are examples of membrane defect intrinsic haemolytic anaemia?
- Hereditary spherocytosis
- elliptocytosis
- pyroporkilocytosis
What are the causes of Intrinsic (Intracorpuscular) Haemolytic anaemia?
- Membrane defects
- Enzyme defects
- Haemoglobin defects
What are examples of enzyme defect intrinsic haemolytic anaemia?
G6PD, PK
What are examples of haemoglobin defect intrinsic haemolytic anaemia?
- Sickle cell
- Thalassaemias
What are examples of immune mediated extrinsic haemolytic anaemia?
- Autoimmune (warm, cold, drug induced)
- Alloimmune (HDN, haemolytic transfusion reaction)
What are examples of non-immune extrinsic haemolytic anaemia?
- Red cell fragmentation syndromes
- Drugs
- Infections
- Hypersplenism
Which of the haemolytic anaemia occur in the vascular system?
- G6PD
- Protein Kinase
- Drug induced autoimmune
- Haemolytic transfusion reaction
- Red cell fragmentation syndromes
- Infections e.g malaria
- March haemoglobinuria
What is the extracellular site of RBC destruction?
- RBCs are engulfed by macrophages in reticuloendothelial system (REM) and broken down to globin, iron and protoporphyrin.
- Globin and iron reused for synthesis of Hb
- Protoporphyrin is broken down to bilirubin and travels to the liver where it is conjugated.
- The conjugated bilirubin goes into small intestine through circulatory system and excreted in the form of Stercobilinogen (in faeces) and via urine in the form of Urobilinogen.
What is the intravascular site of RBC destruction?
- Breakdown of RBCs in the vascular system leaves Hb which gets reabsorbed back into circulation and some goes into the kidney to be excreted in the urine called Haemoglobinuria
- Due to breakdown you also get haemosiderin à haemosiderinuria.
What normally happens when RBCs breakdown?
Macrophages break them down and they go to the liver to be excreted from the kidney
What happens in haemolytic anaemia for RBC breakdown?
RBCs lyse in veins, which leads to haemoglobinurea
What is the cell membrane made up of?
Membrane is made up of a lipid bilayer that has integral peripheral proteins that traverse across
What are the integral proteins normally found in a cell membrane?
- Glycophorin A and C
- Bard 3
What are the cytoskeletal proteins found in the RBC membrane?
- Ankyrin
- Alpha and beta spectrin
- Protein 4.2 and 4.1
- Actin