Haemolytic Anaemias Flashcards
(46 cards)
Clinical features of extravascular haemolysis?
Splenomegaly
Jaundice due to unconjugated bilirubin
Clinical and lab findings of intravascular haemolysis?
Increased free plasma haemoglobin (haemoglobinaemia)
Haemoglobinuria (dark red urine)
Decreased haptoglobin (binds free haemoglobin)
Lab findings of all haemolytic anaemias?
Increased unconjugated bilirubin Increased urobilinogen Increased LDH Reticulocytosis (increased MCV and polychromasia) May have pigmented bile gallstones
Inherited causes of haemolytic anaemias?
Membrane defect: hereditary spherocytosis, hereditary eliptocytosis
Enzyme defect: G6PD deficiency, pyruvate kinase deficiency
Haemoglobinopathies: sickle cell disease, thalassaemias
Acquired causes of haemolytic anaemias?
Immune: autoimmune (warm or cold), alloimmune (haemolytic transfusion reactions)
Non immune: mechanical (metal valves, trauma), PNH, MAHA. Infections (malaria), drugs
Characteristic blood cell in hereditary spherocytosis?
Spherocytes with loss of central pallor
Type of haemolysis seen in hereditary spherocytosis and the clinical finding?
Extravascular
Splenomegaly- spherocytes consumed by splenic macrophages
How is hereditary spherocytosis diagnosed?
Osmotic fragility test
DAT is negative
Treatment for hereditary spherocytosis?
Splenectomy
What are people with hereditary spherocytosis susceptible to?
Increased risk for aplastic crisis with parvovirus B19 infection of erythroid precursors
Inheritance of hereditary spherocytosis?
Autosomal dominant
Inheritance of G6PD deficiency?
X linked
Characteristic blood film of G6PD deficiency?
Heinz bodies
Role of G6PD?
Helps RBCs make glutathione which protects them from OXIDANT damage.
Features seen in G6PD attack?
Rapid anaemia and jaundice
Type of haemolysis in G6PD deficiency?
Intravascular
Get dark urine
How to diagnose G6PD deficiency?
Enzyme assay 2-3 months after a crisis.
Features of pyruvate kinase deficiency?
Autosomal recessive
SEVERE NEONATAL JAUNDICE, splenomegaly, haemolytic anaemia
Inheritance of sickle cell anaemia and the mutation that occurs?
Autosomal recessive
Mutation in beta chain of haemoglobin, single amino acid change of glutamic acid to valine (hydrophobic)
Difference between sickle cell trait and disease?
Trait: HbAS- usually asymptomatic
Disease: HbSS- severe
What increases the risk of sickling?
Hypoxaemia, dehydration and acidosis
What does hydroxurea treatment do?
Increase levels of HbF
HbF protects against sickling; high HbF at birth is protective for the first few months of life.
Type of haemolysis present in sickle cell disease?
Extravascular
What is seen on the blood film for sickle cell disease?
Sickle cells and target cells