Haemolysis Flashcards
What is meant by haemolytic anaemia?
Decompensated haemolysis
- Increased rate of red cell destruction exceeding bone marrow capacity for red cell production
List two consequences of haemolysis?
- Erythroid hyperplasia (increased done marrow red cell production)
- Excess red cell breakdown products such as bilirubin
In what two ways does the bone marrow respond to haemolysis?
- Reticulocytosis
2. Erythroid hyperplasia
Where does extravascular haemolysis usually take place?
Spleen and liver
Where does intravascular haemolysis take place?
Within the circulation
In intravascular or extravascular haemolysis more common?
Extravascular
What is released in excess in extravascular haemolysis?
Protoporphyrin
- unconjugated bilirubin
In which condition would you see pink urine, which turns black when left standing?
Intravascular haemolysis due to haemoglobinuria
Are the products of intravscular haemolysis normal or abnormal?
Abnormal
What investigations would you do if you suspected haemolysis?
- FBC and blood film
- Reticulocyte count
- Serum unconjugated bilirubin
- Serum haptoglobins
- Urinary urobilinogen
Are serum haptoglobins increased or decreased in someone who has haemolysis?
Decreased
What cells on a blood film suggest oxidative damage?
Heinz cells
What cells on a blood film suggest mechanical damage?
Red cell fragments
What types of autoimmune haemolysis are caused by IgG antibodies?
Autoimmune disorders such as SLE
Lymphoproliferative disorders such as B cell lymphoma
Penicillins
What types of autoimmune haemolysis are caused by IgM antibodies?
Infections (EBV)
What test do you do to identify IgG antibodies to red cells?
Direct Coombs Test
What two ways could you get alloimmune haemolysis?
- Immune response, the antibody is produced - eg to a haemolytic transfusion reaction
- Passive transfer of antibody as seen in haemolytic disease of the newborn, ABO incompatibility, Rh D
Is the immediate haemolytic transfusion reaction mediated by IgM or IgG?
IgM (intravascular)
Is the delayed haemolytic transfusion reaction mediated by IgM or IgG?
IgG (extravascular)
What three conditions can cause acquired haemolysis due to membrane defects in the red blood cells?
- Liver disease (Zieve’s syndrome)
- Vitamin E deficiency
- Paroxysmal Nocturnal Haemoglobinuria
Deficiency of which enzyme causes a failure of red blood cells to cope with oxidant stress?
Glucose 6 phosphate dehydrogenase deficiency
What kind of mutation causes sickle cell anaemia?
Point mutation is the beta globin chain
What are the haematological findings in haemolysis?
Raised unconjugated bilirubin Decreased haptoglobin Increased lactate dehydrogenase Increased urobilinogen Reticulocytosis + polychromasia
What % of cell of should be reticulocytes?
2%
