Thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP; also known as Moschcowitz disease) is characterized by the concomitant occurrence of often severe thrombocytopenia, microangiopathic haemolytic anaemia and a variable degree of ischaemic organ damage, particularly affecting the brain, heart and kidneys. Acute TTP was almost universally fatal until the introduction of plasma therapy, which improved survival from <10% to 80-90%. However, patients who survive an acute episode are at high risk of relapse and of long-term morbidity. A timely diagnosis is vital but challenging, as TTP shares symptoms and clinical presentation with numerous conditions, including, for example, haemolytic uraemic syndrome and other thrombotic microangiopathies. The underlying pathophysiology is a severe deficiency of the activity of a disintegrin and metalloproteinase with thrombospondin motifs 13 (ADAMTS13), the protease that cleaves von Willebrand factor (vWF) multimeric strings. Ultra-large vWF strings remain uncleaved after endothelial cell secretion and anchorage, bind to platelets and form microthrombi, leading to the clinical manifestations of TTP. Congenital TTP (Upshaw-Schulman syndrome) is the result of homozygous or compound heterozygous mutations in ADAMTS13, whereas acquired TTP is an autoimmune disorder caused by circulating anti-ADAMTS13 autoantibodies, which inhibit the enzyme or increase its clearance. Consequently, immunosuppressive drugs, such as corticosteroids and often rituximab, supplement plasma exchange therapy in patients with acquired TTP.

Thrombotic thrombocytopenic purpura and cardiac papillary fibroelastoma: a 'unique coexistence'.

Thrombotic thrombocytopenic purpura (TTP), a complex thrombotic microangiopathy, remains an evolving enigma. A 49-year-old African-American woman presented with acute left hemiplegia, an ischemic cerebrovascular accident involving the right middle cerebral artery. Sequential appearance of thrombocytopenia and evidence of microangiopathic haemolysis led to the diagnosis of acquired idiopathic autoimmune TTP. This was managed with plasma exchange (PEX) and steroids. Early haematologic relapse within a month was managed with the addition of rituximab attaining sustained remission. The patient presented 3 years later with acute confusion and expressive aphasia due to multiple infarcts involving the left parieto-occipital cortex. Transoesophageal echocardiography demonstrated a pedunculated 6 mm mitral valvular mass consistent with a papillary fibroelastoma. Anticoagulation was instituted and the patient was continued on therapeutic oral warfarin. A haematologic relapse of TTP eventually emerged and was managed with PEX, steroids and rituximab. This vignette demonstrates several dilemmas in the clinical presentation, diagnosis and management of TTP in current day practice. Rituximab has adjuvant benefits to PEX and is being investigated as potential first-line therapy. Monitoring ADAMTS13 activity and inhibitor titre, as in our case, prove to have prognostic significance. Cardiac fibroelastomas are rare benign cardiac tumours usually arising from valvular endocardium with thromboembolic potential. One of the proposed mechanisms of origin of these masses is organizing thrombi in the setting of endocardial injury and inflammation questioning a possible link to thrombotic microangiopathy. To the best of our knowledge, this is the first report of this unique coexistence.

Evaluation of efficacy and safety of the anti-VWF Nanobody ALX-0681 in a preclinical baboon model of acquired thrombotic thrombocytopenic purpura.

ALX-0681 is a therapeutic Nanobody targeting the A1-domain of VWF. It inhibits the interaction between ultra-large VWF and platelet GpIb-IX-V, which plays a crucial role in the pathogenesis of thrombotic thrombocytopenic purpura (TTP). In the present study, we report the efficacy and safety profile of ALX-0681 in a baboon model of acquired TTP. In this model, acute episodes of TTP are induced by administration of an ADAMTS13-inhibiting mAb. ALX-0681 completely prevented the rapid onset of severe thrombocytopenia and schistocytic hemolytic anemia. After induction of TTP, platelet counts also rapidly recovered on administration of ALX-0681. This effect was corroborated by the full neutralization of VWF activity. The schistocytic hemolytic anemia was also halted and partially reversed by ALX-0681 treatment. Brain CT scans and post mortem analysis did not reveal any sign of bleeding, suggesting that complete neutralization of VWF by ALX-0681 under conditions of thrombocytopenia was not linked with an excessive bleeding risk. The results obtained in this study demonstrate that ALX-0681 can successfully treat and prevent the most important hallmarks of acquired TTP without evidence of a severe bleeding risk. Therefore, ALX-0681 offers an attractive new therapeutic option for acquired TTP in the clinical setting.

Acute arterial thrombotic purpura complicating varicella and the role of hyperbaric oxygen as an adjunctive therapy.

Chickenpox is a common infectious disease of the pediatric age group with rare complications such as hemorrhagic varicella and arterial thrombotic purpura. Medical support is the mainstay of treatment in such cases but for the rescue of necrotic tissues, hyperbaric oxygen (HBO) therapy should be applied in addition to anticoagulant intervention. We report an infant with acute arterial thrombotic purpura which developed after varicella eruption and who made full recovery with the help of HBO as an adjunctive treatment modality. Fresh frozen plasma and low molecular weight heparin were given for prolonged prothrombin time and thromboemboli on the 2nd-4th digits of his right foot. Protein C, protein S and factor V levels were found to be normal in our patient. Necrotic lesions on the toes regressed with repeated HBO treatment and amputation was not needed.

Pylethrombosis associated with gastric cancer in Moschcowitz's disease: successful management with anticoagulant. Report of a case.

Portal vein thrombosis secondary to gastric cancer has been rarely reported. The main difficulty is represented by the correct differential diagnosis between benign and malignant thrombus and therefore by its treatment. In this report we describe a 62-year-old woman with Moschcowitz's disease who developed pylethrombosis and gastric cancer. Preoperative examination confirmed the relationship between the portal vein thrombosis and Moschcowitz's disease. She underwent an aggressive surgical procedure for the gastric cancer and conservative treatment of the thrombosis with subcutaneus administration of 8000 IU/day of low molecular weight heparin (LMWH) at the time of diagnosis, interrupted eight hours before surgery and resumed eight hours after with 4000 IU/day. At discharge LMWH treatment was replaced with oral sodium warfarin home treatment to keep the international normalized ratio range between 2 and 3. Regression of the thrombosis with low molecular weight heparin was confirmed by computed tomography. The patient survived more than two years. We believe that patients with gastric cancer complicated by benign partial portal vein thrombosis could gain particular benefit from adjuvant anticoagulant treatment, so that the surgical approach can be limited to gastric cancer.

Adverse reactions associated with mobile therapeutic apheresis: analysis of 17,940 procedures.

In order to evaluate the nature and frequency of adverse reactions associated with Therapeutic Apheresis (TA), database information from two large mobile apheresis services was analyzed. A total of 17,940 procedures performed on 3,583 patients were studied using an Access Database. Seventy percent (12,558) of the procedures were performed on a Fresenius AS104 blood cell separator and 30% (5,382) were performed on a COBE Spectra. The five most commonly treated diseases were Guillain-Barre Syndrome (25%), thrombotic thrombocytopenic purpura (20%), myasthenia gravis (18%), the hyperviscosity syndrome (12%), and chronic inflammatory demyelinating polyneuropathy (9%). All patients received calcium gluconate supplement during the procedures. Cardiac monitoring was used during 80% of the procedures and blood pressure monitoring was used during all procedures. All procedures were supervised by a physician. Both apheresis services fully comply with the ASFA Guidelines for Therapeutic Apheresis Providers. Adverse reactions occurred in 3.9% of all procedures. The following adverse reactions were documented: reactions related to ACD toxicity (3%), vasovagal reactions (0.5%), vascular access related complications (0.15%), reactions related to FFP (0.12%), hepatitis B from FFP (0.06%), arrhythmias (0.01%), hemolysis due to inappropriate dilution of 25% albumin (0.01%), and one death (from underlying disease) during a TA procedure (0.006%). These data demonstrate that therapeutic apheresis is associated with a low rate of side effects when performed by well-trained and certified nurses under the direction of experienced physicians, even in the diverse setting of large mobile therapeutic apheresis programs.

[Microangiopathic hemolytic anemias. Clinical pattern, therapy and clinical course in 14 patients with thrombotic thrombocytopenic purpura and hemolytic uremic syndrome]. / Die mikroangiopathischen hämolytischen Anämien. Klinik, Therapie und Verlauf bei 14 Patienten mit thrombotisch-thrombozytopenischer Purpura und hämolytisch-urämischem Syndrom.

Thrombotic thrombocytopenic purpura (TTP) and the hemolytic uremic syndrome (HUS) have in common a microangiopathic hemolytic anemia involving disseminated platelet aggregation and endothelial damage of the microvasculature mainly of the brain (TTP) and kidney (HUS). The underlying pathomechanism still remains unclear. The disease takes an acute, dramatic and frequently fatal course. Unfortunately a broadly approved therapeutic regimen is still lacking since the rarity of TTP and HUS makes study of a large group of patients impossible. We have observed and treated 14 patients with TTP and HUS during a period of 9 years. Most of the cases have been triggered by infectious diseases and pregnancy. Diagnostic cornerstones were hemolytic anemia, schistocytes on peripheral blood smears and consumption thrombocytopenia. Renal and cerebral symptoms were observed regularly, whereas lesions of the pancreas, liver and heart were much less frequent. The treatment included plasma transfusion (47%), plasma exchange (42%), high dose corticosteroids (74%), antiplatelet agents (53%), vitamin E (32%) and vincristin (11%). The outcome of 19 episodes of TTP or HUS was as follows: in 78% complete recovery, in 11% persistence of impaired renal function, and in 11% death. From analysis of our cases it is concluded that plasma transfusions and high dose corticosteroids improve the prognosis of TTP and HUS significantly.