Paroxysmal nocturnal haemoglobinuria and hypoplastic MDS (Myelodysplastic syndrome)
Last updated: Friday, 24, December, 2010
PNH is a rare clonal haemopoietic disorder, which can arise either spontaneously or in patients who have previously been treated with immunosuppression for aplastic anaemia.
It overlaps with the MDS - myelodysplastic syndromes and is characterised by by an increased sensitivity to complement of the haemopoietic cells, haemolysis, iron deficiency secondary to loss of haemosiderin in the urine, and an increased risk of venous and arterial thrombosis.
Iron replacement often leads to an increase in haemolysis.
FBC, blood film, differential WCC, platelet count; direct antiglobulin test; reticulocyte count.
Diagnosis may be made with flow cytometry for PNH to detect absent or diminished expression e.g. Glyco phosphatidyl inositol (GPI) linked cell surface proteins on red cells or white cell sub-populations. At least two antigens should show abnormal binding so as to exclude a congenital absence of a single receptor.
Haemosiderin - urine. Bone marrow aspiration and trephine biopsy.
There is long term risk of major thrombotic episodes.