Haemolytic anaemia characterised by evidence of intravascular haemolysis such as haemoglobinuria and elevation of plasma lactate dehydrogenase.
Diagnosis can be made by flow cytometry of granulocytes and RBCs, looking for the lack of the glycosylphosphatidylinositol anchor or of proteins dependent on it for attachment to the cell membrane.
Complicated by thrombosis, particularly of hepatic and other intra-abdominal veins, cerebral veins, and other usual and unusual venous sites.
Specifically treated with a monoclonal antibody to the fifth component of complement (eculizumab).
May arise in patients with or recovering from aplastic anaemia, and it may manifest with cytopoenias that are the result of marrow hypoproduction, which may respond to treatment for aplastic anaemia.
Paroxysmal nocturnal haemoglobinuria (PNH) is an acquired disorder of the blood characterised by intravascular haemolysis and thrombophilia due to the absence of glycosylphosphatidylinositol-anchored proteins on the membrane surface of blood cells.It is associated with relative or absolute marrow hypoplasia.
History and exam
Key diagnostic factors
- Budd-Chiari syndrome
Other diagnostic factors
- history of aplastic anaemia
- abdominal pain
- dysphagia and odynophagia
- erectile dysfunction
- bleeding diathesis
- neurological signs and symptoms
- aplastic anaemia/hypoplastic bone marrow
1st investigations to order
- urine dipstick
- urine microscopy
- reticulocyte count
- serum LDH
- unconjugated bilirubin
Investigations to consider
- flow cytometry for GPI anchor or anchored proteins
- fluorescent aerolysin
- antiglobulin (Coombs) test
- serum iron, serum ferritin
- serum creatinine and urea
classic PNH (haemolytic anaemia): non-pregnant
classic PNH (haemolytic anaemia): pregnant
PNH in the setting of another specific bone marrow disorder: non-pregnant
PNH in the setting of another specific bone marrow disorder: pregnant with thrombosis
PNH in the setting of another specific bone marrow disorder: pregnant without thrombosis
subclinical PNH: non-pregnant
subclinical PNH: pregnant
following acute clinical PNH with thrombosis: non-pregnant
Ilene Ceil Weitz, MD
Associate Professor of Clinical Medicine
Jane Anne Nohl Division of Hematology
Keck-USC School of Medicine
ICW receives speaker honoraria from and undertakes consultancy for Alexion Pharmaceuticals.
Dr Ilene Ceil Weitz would like to gratefully acknowledge Dr Wendell F. Rosse, the previous contributor to this topic. WFR serves on advisory boards and educational faculties for Alexion Pharmaceuticals.
David Dingli, MD, PhD
Associate Professor of Medicine
DD declares that he has no competing interests.
Panayiotis D. Ziakas, MD, MSc, PhD
Department of Pathophysiology
University of Athens
PDZ declares that he has no competing interests.
- Autoimmune haemolytic anaemia, warm antibody type
- Microangiopathic haemolytic anaemia
- Paroxysmal cold haemoglobinuria
- Consensus guidelines to detect GPI‐deficient cells in paroxysmal nocturnal hemoglobinuria (PNH) and related disorders: Part 1 – clinical utility
- The physician's guide to paroxysmal nocturnal hemoglobinuria (PNH)
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