Paroxysmal nocturnal haemoglobinuria

Paroxysmal nocturnal haemoglobinuria (PNH) is a 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 red blood cells, 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.

Treatment includes monoclonal antibodies which inhibit complement protein C5, and pegcetacoplan for patients who may not respond well to C5 complement blockade.

May arise in patients with or recovering from aplastic anaemia. It may also manifest with cytopoenias that are the result of marrow hypoproduction.

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.[1]Rosse W. Paroxysmal nocturnal hemoglobinuria as a molecular disease. Medicine (Baltimore). 1997 Mar;76(2):63-93. http://www.ncbi.nlm.nih.gov/pubmed/9100736?tool=bestpractice.com [2]Parker CJ. Update on the diagnosis and management of paroxysmal nocturnal hemoglobinuria. ASH Education Book 2016;2016(1):208-16. https://ashpublications.org/hematology/article/2016/1/208/21101/Update-on-the-diagnosis-and-management-of http://www.ncbi.nlm.nih.gov/pubmed/27913482?tool=bestpractice.com ​It often results in suppressed haematopoiesis, including frank aplastic anaemia.