Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) occurs when abnormal blood-forming stem cells produce red blood cells with a defective protective layer.  An abnormal platelet function is also detectable among patients with PNH. History. Doctors first recognized PNH in 1866 when examining a man working with chemicals.  The disease was initally called "intermittent haematinuria".  In 1928, the term "paroxysmal nocturnal hemoglobinuria" was used.   Blood and bone marrow findings. Patients with PNH have low red blood cells counts caused by the destruction, or hemolysis, of red blood cells in the blood stream.  This destruction occurs when the blood cells lack a necessary surface molecule, GP1. They are destroyed by the complement which is the part of the immune system.

Symptoms.  Red blood cell destruction often causes the urine to become dark or red in color.  The patient may experience other symptoms, such as back pain, easy bruising of the skin, blood clots, abdominal discomfort, and liver failure.  

Tests for diagnosis. Several tests are used to diagnosis PNH, including: Complete Blood Count, Sucrose Hemolysis Test, Ham's Test, flow cytometry, urinalysis, and serum hemoglobin.   Course of the disease. PNH is not inherited.  It often occurs as an isolated disorder.  However, it also arises in an estimated 30% of aplastic anemia cases and in some patients with MDS.  In addition, PNH may evolve into acute myelogenous leukemia. Treatment.  Generally the course of treatment is conservative, depending upon the severity of the symptoms experienced by PNH patients. Eculizumab (Soliris) is the only drug approved by the FDA for the treatment of PNH.  It was approved on March 16, 2007. Transfusions may be needed when hemoglobin decreases. Patients who have blood clots are treated with blood thinners if platelet counts are adequate. Stem cell transplantation is the only known therapy for a cure. Best results are achieved in younger patients with a matched sibling donor. Low platelets and low white blood cells counts in PNH patients can be successfully treated with the same immunosuppressive therapy used in aplastic anemia. Ask your hematologist about all treatment options. Each AA&MDSIF Information Packet contains a Managing Treatment Decisions brochure which explains the information you need to make an informed decision that is right for you. It includes questions that need to be answered before you agree to any treatment option. To request a free copy of this information packet, please click here. Overview of Bone Marrow Diseases Bone Marrow and Blood Production Aplastic Anemia Myelodysplastic Syndromes Learn More About Your Disease Glossary Last Modified:  October 30, 2006