Abstract

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal stem cell disorder characterized by intravascular hemolytic anemia that results from the clonal expansion of hematopoietic stem cells harboring somatic mutations in an X-linked gene, termed PIG-A (phosphatidylinositol glycan class A). PIG-A mutations block glycosylphosphatidylinositol (GPI) anchor biosynthesis, resulting in a deficiency or absence of all GPI-anchored proteins on the cell surface. CD55 and CD59 are GPI-anchored complement regulatory proteins. Their absence on PNH red cells is responsible for the complement-mediated intravascular hemolysis, leading to the release of free hemoglobin, which contributes to many of the clinical manifestations of PNH including fatigue, pain, esophageal spasm and possibly serious thrombotic episodes [1]. Allogeneic hematopoietic stem cell transplantation is the only curative therapy for PNH. The complement inhibitor eculizumab, a humanized monoclonal antibody against C5, that inhibits terminal complement activation, recently approved in the US, has been shown to reduce hemolysis, decrease the erythrocyte transfusion requirements and the risk for thrombosis, and to improve quality of life of PNH patients [2, 3]. Major morbidity and mortality with PNH are often ascribed to the development of venous thromboembolism (VTE) [1–6], and several patients have recurrent thromboses [7]. VTE in PNH patients occur mostly at unusual sites. Data from a recent review report hepatic vein thrombosis, leading to Budd-Chiari syndrome (BCS), as the most frequent (40.7%) thrombotic complication, accounting for the majority of deaths [8], followed by cerebral vein and sinus thromboses, superior sagittal sinus being the most frequently involved site [8]. Inherited thrombophilia may increase the risk of serious thromboembolic events in PNH patients [9]. In patients experiencing VTE, early anti-thrombotic therapy (heparin, thrombolysis) aimed to limit the extension of thrombosis, or to dissolve formed thrombi, should improve the prognosis of this severe complication. PNH patients suffering from VTE should be treated with anticoagulant drugs indefinitely [1]. Thrombocytopenia often complicates PNH, and this issue must be addressed when an anticoagulation management plan is formulated [1]. Recurrent, life-threatening thrombosis merits consideration for bone marrow transplantation (BMT) [1]. Over the past few years significant advances in other therapeutic approaches, such as transjugular intrahepatic portosystemic shunt (TIPS), have contributed to the improvement of survival in this setting [8]. We report the case of a 29-year-old woman, R. D. The family history was negative for VTE and cardiovascular disease. She was a non-smoker. And had been slightly overweight since childhood. When she was 19 years old, an isolated moderate thrombocytopaenia (50,000/mmc) was detected although in the absence of bleeding. As idiopathic thrombocytopaenia was diagnosed, she was treated with long-term steroids, with an improvement in the platelet count (120,000/mmc). At the age of 27, while on oral contraceptives for 3 months, she experienced a sudden occurrence of headache and visual loss, followed by seizures and coma. A computed tomography (CT scan) showed multiple cerebral venous thromboses. Screenings A. Tufano (&) N. Macarone Palmieri E. Cimino A. M. Cerbone Regional Reference Centre for Coagulation Disorders, Department of Clinical and Experimental Medicine, Federico II University of Naples, Via S. Pansini, 5, 80131 Naples, Italy e-mail: atufano@unina.it

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