Haemolytic anaemia Flashcards
Define
DEFINITION: premature erythrocyte breakdown causing shortened erythrocyte life span (< 120 days) with anaemia
Causes
Hereditary
Membrane Defects
- Hereditary spherocytosis
- Elliptocytosis
Metabolic Defects
- G6PD deficiency
- Pyruvate kinase deficiency
- Haemoglobinopathies
Sickle cell disease
- Thalassemia
- Acquired
Autoimmune
- Antibodies attach to erythrocytes causing intravascular and extravascular haemolysis
- Isoimmune
- Transfusion reaction
Haemolytic disease of the newborn
- Drugs
- Penicillin
- Quinine
NOTE: this is caused by the formation of a drug-antibody-erythrocyte complex
- Trauma
- Microangiopathic haemolytic anaemia (caused by RBC fragmentation in abnormal microcirculation)
E.g. haemolytic uraemic syndrome, DIC, malignant hypertension
- Infection
- Malaria
- Sepsis
- Paroxysmal nocturnal haemoglobinuria
Epidemiology
COMMON
Genetic causes are prevalent if African, Mediterranean and Middle Eastern populations
Hereditary spherocytosis is the most common inherited haemolytic anaemia in northern Europe
Symptoms
Jaundice
Haematuria
Anaemia
Signs
Pallor
Jaundice
Hepatosplenomegaly
Investigations
Bloods
- FBC:
- Low Hb
- High reticulocytes
- High MCV
- High unconjugated bilirubin
- Low haptoglobin (a protein that binds to free Hb released by red blood cells)
- U&Es
- Folate
Blood Film
- Leucoerythroblastic picture
- Macrocytosis
- Nucleated erythrocytes or reticulocytes
- Polychromasia
- May identify specific abnormal cells such as:
Spherocytes
Elliptocytes
Sickle cells
Schistocytes
Malarial parasites
Urine
- High urobilinogen
- Haemoglobinuria
- Haemosiderinuria
Direct Coombs’ Test
- Tests for autoimmune haemolytic anaemia
- Identifies erythrocytes coated with antibodies
- Osmotic fragility test or Spectrin mutation analysis
- Identifies membrane abnormalities
Ham’s Test
Lysis of erythrocytes in acidified serum in paroxysmal nocturnal haemoglobinuria
Hb Electrophoresis or Enzyme Assays
To exclude other causes
Bone Marrow Biopsy (rarely performed)
