Haematology >
Haemolytic Anaemia
“Anaemia secondary to reduced survival of red blood cells (RBCs)”
- Destruction of RBCs- broadly defined as a reduction in the life span below 100 days (normal 110-120 days)
- Classifications:
- Inherited vs Acquired
- Intravascular vs Extravascaular
Risk Factors
- Family history
- Genes for metabolic, haemoglobin, and membrane defects
- Drugs- penicillins, cephalosporins, sulfonamides, sulfasalazine
- Infections – mycoplasma pneumoniae
Aetiology
- Genetic:
- RBC membrane abnormalities- hereditary spherocytosis
- Haemoglobin abnormalities- sickle cell, thalassaemia
- Metabolic defects- G6PD deficiency
- Acquired:
- Immune- haemolytic disease of newborn, blood transfusion reaction
- Autoimmune- idiopathic, SLE, chronic lymphatic leukaemia, infections
- Drugs
Pathophysiology
- Two mechanisms:
- Intravascular
- Due to complement fixation, trauma, or other extrinsic factors
- Prosthetic valves, cardiac valves, G6PD deficiency, disseminated intravascular coagulation
- Extravascular (most common)
- RBCs removed from the circulation because they are either intrinsically defective or because of bound immunoglobulins to their surfaces
- Intravascular
Clinical Presentation
- Symptoms:
- Fatigue
- Weakness
- Paraesthesia
- Dyspnoea
- GI symptoms (nausea, dyspepsia)Weight loss
- Signs:
- Atrophic glossitis
- Pallor
- Fever
- Splenomegaly
- Evidence of underlying disease
- Haemolysis:
- Jaundice
- Abdominal pain (eg gallstones)
- Dark urine (haemoglobinuria secondary to intravascular haemolysis)
Investigations
- Haemolytic screen:
- FBC including reticulocyte count
- Blood film
- LDH
- LFTs (bilirubin)
- Serum haptoglobin
- Other tests:
- Direct anti-globulin test
- Indirect anti-globulin test
- Haemoglobin electrophoresis
- Sickle cell screening
- Traditionally causes a NORMOCYTIC ANAEMIA
Management
- Conservative: n/a
- Medical:
- Administer folic acid
- Discontinue meds causing haemolysis
- Transfusion therapyIron therapy
- Autoimmune haemolytic anaemia therapy:
- Corticosteroids
- Azathioprine and cyclophosphamide if steroids fail
- Rituximab
- Surgical:
- Splenectomy
Complications
- High-output cardiac failure
- Jaundice
- Iron deficiency