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Alternative names Return to top
PNHDefinition Return to top
Paroxysmal nocturnal hemoglobinuria is a rare, acquired disorder of red blood cells in which an abnormal cell surface molecule leads to premature destruction of the cells. This destruction is intermittent (paroxysmal).Causes, incidence, and risk factors Return to top
PNH is caused by a defect in the formation of a red cell surface protein anchor, called GP1. As a result of the lack of this surface protein anchor, a number of surface proteins are unable to remain tethered to the cell surface. This includes the protein CD55, or Decay Accelerating Factor (DAF).
The result of the loss of these cell surface proteins is an enhanced sensitivity to complement-mediated cell destruction. (Complement is a substance produced by the immune system.) The disease can affect people of any age.
Red blood cell, white blood cell, and platelet counts may be low. Urine may be intermittently red or brown, signifying the breakdown of red blood cells with release of hemoglobin into the circulation and then the urine.
Blood clots may form in some people. The disease may arise in relation to aplastic anemia, and may progress to acute myelogenous leukemia. Risk factors, except for prior aplastic anemia, are not known.
Symptoms Return to top
Signs and tests Return to top
Treatment Return to top
Steroids may be effective in suppressing hemolysis. Blood transfusions may be required. Anticoagulation therapy may also be required to prevent clot formation.
Bone marrow transplantation can cure this disease.
Expectations (prognosis) Return to top
The outcome is variable, with most people surviving approximately 10 years following diagnosis. In rare cases, the abnormal cells may decrease over time. Death can be caused by complications of blood clot formation (thrombosis).Complications Return to top
Calling your health care provider Return to top
Call your health care provider if you find blood in your urine, if symptoms worsen or do not improve with treatment or if new symptoms develop.
Prevention Return to top
There is no known way to prevent this disorder. Update Date: 10/13/2003 Updated by: Corey Cutler, M.D., M.P.H., F.R.C.P.C, Department of Medical Oncology, Dana-Farber Cancer Institute; Instructor in Medicine, Harvard University, Boston, MA. Review provided by VeriMed Healthcare Network.
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Page last updated: 28 October 2004 |