Haemolytic anaemias Flashcards
What is haemolytic anaemia?
Anaemia due to the destruction of premature RBCs before their normal lifespan of 120 days
Where can haemolysis occur?
Intravascular -> in the circulation
Extravascular -> in the reticuloendothelial system
Macrophages, liver, spleen and bone marrow
What are signs of increased red cell breakdown?
- MCV normal or increased
- Increased bilirubin
- Increased urobilinogen
- Increased serum LDH (lactate dehydrogenase)
What are signs of increased red cell production?
Increased reticulocytes (large, immature RBCs)
What suggests extravascular haemolysis?
Splenomegaly
What suggests intravascular haemolysis?
- Increased free plasma Hb released from RBCs
- Methalbuminaemia
- Decreased plasma haptoglobinuria
- Haemoglobinuria
- Haemosiderinuria
What investigations would you order of haemolytic anaemia?
• FBC
• Reticulocytes
• Bilirubin
• LDH
• Haptoglobin
• Urinary urobilinogen
• Blood film
• Specific
Coomb’s test
EMA-binding
Glucose-6-phosphate dehydrogenase level
Haemoglobin identification (HPLC)What are congenital causes of haemolytic anaemia?
o RBC membrane (hereditary elliptocytosis, hereditary spherocytosis, hereditary stomatocytosis)
o RBC enzyme deficiencies (G6PD, pyruvate kinase)
o RBC haemoglobin disorders (thalassaemia, sickle cell disease)
What are the acquired causes of haemolytic anaemia?
o Autoimmune haemolysis (AIHA)
o Microangiopathic haemolytic anaemia (HUS, TTP, DIC)
o Drugs, infections, toxins
o Copper deficiency (Wilson’s disease)
What is elliptocytosis?
Autosomal dominant
Red cells are elliptocytic in shape
What is hereditary spherocytosis?
Autosomal dominant
inherited abnormalities of red cell membrane proteins
What does hereditary spherocytosis often present with?
- Neonatal jaundice
- Gallstones -> cholecystectomy and splenectomy
How do you diagnose hereditary spherocytosis?
- Family Hx present in 75% of cases
- FBC
- Reticulocyte count
- Blood film
Micro-spherocytes and polychromatic macrocytes
If there are none of the above:
- EMA-binding
Weak fluorescence
What is hereditary stomatocytosis?
- Autosomal dominant
- Many red cells have mouth-like slits of central pallor
- Abnormality with sodium pump
What is glucose-6-phosphate dehydrogenate (G6PD) deficiency?
- X-linked
- ‘Bite’ cells
What are the symptoms of glucose-6-phosphate dehydrogenate (G6PD) deficiency?
Sudden onset of:
o Feeling unwell and lack energy
o Become pale and yellow in colour have a backache
o Passing dark coloured urine (Hb that has leaked through glomerulus)
What must patients avoid in glucose-6-phosphate dehydrogenate (G6PD) deficiency?
Food
- Fava beans
- Broad beans
Drugs
- Many anti-malarial drugs
- Aspirin (large doses)
- Chloramphenicol
- Dapsone
- Phenylhydrazine
- Nalidixic acid
- Nitrofurantoin
- Vitamin K
Precipitants
-Henna
What is pyruvate kinase deficiency?
- Autosomal recessive
- ‘Sputnik cells’ with protruding spikes
What is sickle cell disease?
- Autosomal recessive
- Beta globin variant
HbAS -> carriers/sickle cell trait
HbSS -> Homozygous
Which groups is sickle cell disease most common in?
African patients
How is sickle cell anaemia diagnosed?
- Normal MCV
- Normocytic RBCs with sickle cells
Why are blood transfusions not required in sickle cell anaemia?
Oxygen dissociation curve if sickle Hb is shifted to the tight and oxygen is more readily released into tissues
What is a sickle cell crisis?
Small blood vessels are occluded by sickle shaped cells which cause infarction of the tissues.
What is a vaso-occlusive (painful) sickle crisis?
Small blood vessel are occluded:
- Bone marrow
- Kidney
- Brain (stroke)
- Spleen
