Paroxysmal nocturnal haemoglobinuria is a rare disease in which erythrocytes lack glycosylphosphatidylinositol (GPI) which leaves them susceptible to complement-mediated haemolysis.
Features of paroxysmal nocturnal haemoglobinuria include:
- Dark urine in the morning
- Haemolytic anaemia
- Thrombosis
- mainly venous
- can occur anywhere but classically affect the hepatic veins causing abdominal pain
- Pancytopenia
The lack of GPI is caused by a mutation of the PIG-A gene.
Investigations
- Bloods – anaemia, raised reticulocyte count, raised LDH
- Flow cytometry - CD55 and CD59
- Ham test (now largely replaced by flow cytometry)
Treatment
- Allogeneic haematopoietic stem cell transplantation – curative if match available
- transfusions
- Eculizumab
- monoclonal antibody against C5
- decreases haemolysis and need for transfusions
- increased risk of neisserial infections therefore patients need vaccination against neisseria meningitides
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